BMC Medicine. 2023 Feb. 21:46. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
Dual-specificity phosphatases 22-deficient T cells contribute to the pathogenesis of ankylosing spondylitis.
Dual-specificity phosphatases (DUSPs) can dephosphorylate both tyrosine and serine/threonine residues of their substrates and regulate T cell-mediated immunity and autoimmunity. The aim of this study was to investigate the potential roles of DUSPs in ankylosing spondylitis (AS).

Sixty AS patients and 45 healthy controls were enrolled in this study. Associations of gene expression of 23 DUSPs in peripheral T cells with inflammatory cytokine gene expression and disease activity of AS were analyzed. Finally, we investigated whether the characteristics of AS are developed in DUSP-knockout mice.

The mRNA levels of DUSP4, DUSP5, DUSP6, DUSP7, and DUSP14 in peripheral T cells were significantly higher in AS group than those of healthy controls (all p < 0.05), while DUSP22 (also named JKAP) mRNA levels were significantly lower in AS group than healthy controls (p < 0.001). The mRNA levels of DUSP4, DUSP5, DUSP6, DUSP7, and DUSP14 in T cells were positively correlated with mRNA levels of tumor necrosis factor-α (TNF-α), whereas DUSP22 was inversely correlated (all p < 0.05). In addition, inverse correlations of DUSP22 gene expression in peripheral T cells with C-reactive protein, erythrocyte sedimentation rate, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were observed (all p < 0.05). More importantly, aged DUSP22 knockout mice spontaneously developed syndesmophyte formation, which was accompanied by an increase of TNF-α+, interleukin-17A+, and interferon-γ+ CD3+ T cells.

DUSP22 may play a crucial role in the pathogenesis and regulation of disease activity of AS….detail


icon-achiEMBO Molecular Medicine. 2022 July. e15904. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
SARS-CoV-2 spike protein enhances MAP4K3/GLK-induced ACE2 stability in COVID-19.
Abstract : ACE2 on epithelial cells is the SARS-CoV-2 entry receptor. Single-cell RNA-sequencing data derived from two COVID-19 cohorts revealed that MAP4K3/GLK-positive epithelial cells were increased in patients. SARS-CoV-2-induced GLK overexpression in epithelial cells was correlated with COVID-19 severity and vesicle secretion. GLK overexpression induced the epithelial cell-derived exosomes containing ACE2; the GLK-induced exosomes transported ACE2 proteins to recipient cells, facilitating pseudovirus infection. Consistently, ACE2 proteins were increased in the serum exosomes from another COVID-19 cohort. Remarkably, SARS-CoV-2 spike protein-stimulated GLK, and GLK stabilized ACE2 in epithelial cells. Mechanistically, GLK phosphorylated ACE2 at two serine residues (Ser776, Ser783), leading to the dissociation of ACE2 from its E3 ligase UBR4. Reduction in UBR4-induced Lys48-linked ubiquitination at three lysine residues (Lys26, Lys112, Lys114) of ACE2 prevented its degradation. Furthermore, SARS-CoV-2 pseudovirus or live virus infection in humanized ACE2 mice induced GLK and ACE2 protein levels, and ACE2-containing exosomes. Collectively, ACE2 stabilization by SARS-CoV-2-induced MAP4K3/GLK may contribute to the pathogenesis of COVID-19….detail
Theranostics. 2022 July. 12:5744-5760. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuangicon-achi
MAP4K3 inhibits Treg differentiation by direct phosphorylating IKKβ and inducing IKKβ-mediated FoxO1 nuclear export and Foxp3 downregulation.
Rationale: GLK (MAP4K3) activates PKCθ-IKKβ axis in T-cell activation and induces IL-17A-mediated autoimmune diseases. Attenuation of Treg differentiation and function by GLK could also contribute to autoimmune diseases.

Methods: We analyzed the roles of GLK and IKKβ in Treg differentiation and function using T-cell-specific GLK transgenic mice and IKKβ conditional knockout mice. The mechanism of GLK/IKKβ-mediated attenuation of Treg differentiation/function was studied by chromatin-immunoprecipitation, reporter assays, in vitro kinase assays, protein-protein interaction assays, mass spectrometry, confocal microscopy, flow cytometry, and single-cell RNA sequencing (scRNA-seq) analysis.

Results: We found that GLK signaling inhibited Foxp3 transcription by blocking the function of the transcription factor FoxO1. Mechanistically, GLK directly phosphorylated and activated IKKβ at Ser733 in a PKCθ-independent manner. The phospho-IKKβ Ser733 induced FoxO1 Ser319 phosphorylation and nuclear export, leading to Foxp3 downregulation. Consistently, scRNA-seq analyses showed that Foxp3 mRNA levels were inversely correlated with FoxO1 mRNA levels in GLK transgenic CD4+ T cells.

Conclusions: GLK-IKKβ-FoxO1 signaling axis inhibits Foxp3 transcription, leading to reduction of Treg differentiation and suppressive activity, as well as induction of autoimmune disease….detail

icon-achiiScience. 2022 Feb. 25:103738. Dr. Cheng-Yuan Kao
Single-cell RNA sequencing uncovers the individual alteration of intestinal mucosal immunocytes in Dusp6 knockout mice.
Summary: Single-cell RNA sequencing (scRNA-seq) approach can broadly and specifically evaluate the individual cells with minimum detection bias. To explore the individual compositional and transcriptional alteration of intestinal leukocytes in the Dual Specificity Phosphatase 6 knockout (D6KO) mice, we performed a scRNA-seq followed by the cell type annotation based on ImmGen database. Composition assessments found that D6KO-derived intestinal leukocytes tend to stay inactivate or immature status. The enrichment analysis showed that D6KO-derived intestinal leukocytes are less sensitive to microbes. The modPhEA phenotypic analysis showed that the D6KO leukocytes may link to not only immune-associated but also diverse previously-non-immune-related diseases. Integrating our dataset with the published dataset GSE124880 generated a comprehensive dataset for exploring intestinal immunity. Down-regulation of Ccl17 gene was found in the D6KO-derived dendritic cells. Our results demonstrated the advantage of applying scRNA-seq for dissecting the individual alteration of intestinal leukocytes, particularly in the D6KO mice at a naïve state….detail
icon-achiAnnals of the Rheumatic Diseases. 2022 Feb. 81:243-254. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
Genomic sequencing and functional analyses identify MAP4K3/GLK germline and somatic variants associated with systemic lupus erythematosus.
Objectives: MAP4K3 (GLK) overexpression in T cells induces interleukin (IL)-17A production and autoimmune responses. GLK overexpressing T-cell population is correlated with severity of human systemic lupus erythematosus (SLE); however, it is unclear how GLK is upregulated in patients with SLE.

Methods: We enrolled 181 patients with SLE and 250 individuals without SLE (93 healthy controls and 157 family members of patients with SLE) in two independent cohorts from different hospitals/cities. Genomic DNAs of peripheral blood mononuclear cells were subjected to next-generation sequencing to identify GLK gene variants. The functional consequences of the identified GLK germline or somatic variants were investigated using site-directed mutagenesis and cell transfection, followed by reporter assays, mass spectrometry, immunoblotting, coimmunoprecipitation, and in situ proximity ligation assays.

Results: We identified 58 patients with SLE from Cohort #1 and #2 with higher frequencies of a somatic variant (chr2:39 477 124 A>G) in GLK 3′-untranslated region (UTR); these patients with SLE showed increased serum anti-double-stranded DNA levels and decreased serum C3/C4 levels. This somatic variant in 3′-UTR enhanced GLK mRNA levels in T cells. In addition, we identified five patients with SLE with GLK (A410T) germline variant in Cohort #1 and #2, as well as two other patients with SLE with GLK (K650R) germline variant in Cohort #1. Another GLK germline variant, A579T, was also detected in one patient with SLE from Cohort #2. Both GLK (A410T) and GLK (K650R) mutants inhibited GLK ubiquitination induced by the novel E3 ligase makorin ring-finger protein 4 (MKRN4), leading to GLK protein stabilisation.

Conclusions: Multiple GLK germline and somatic variants cause GLK induction by increasing mRNA or protein stability in patients with SLE….detail

icon-achiArthritis & Rheumatology. 2022 Jan. 74: 92-104. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
Induction of interferon-γ and tissue Inflammation by overexpression of eosinophil cationic protein in T cells and exosomes.
Objectives: T cells play critical roles in the pathogenesis of systemic lupus erythematosus (SLE). Serum-derived exosomes are increased in SLE patients and are correlated with disease severity. The proteins in the T-cell-derived exosomes from SLE patients could play important roles in SLE pathogenesis.

Methods: We characterized proteins of SLE T cell-derived exosomes by exosome MACSPlex analysis and proteomics using T-cell supernatants from SLE patients and healthy controls. To study the potential pathogenic functions of the identified exosomal protein, we generated and characterized T-cell-specific transgenic mice that overexpressed the identified protein in T cells.

Results: We identified eosinophil cationic protein (ECP, also named human RNase 3) that was overexpressed in SLE T cell-derived exosomes. T-cell-specific ECP transgenic mice displayed early induction of serum IFN-γ levels and multi-tissue inflammation. The aged T-cell-specific ECP transgenic mice also displayed an increase of follicular helper T cells, plasma B cell, and autoantibodies. Single-cell RNA sequencing (scRNA-seq) also showed the induction of IFN-γ mRNA and inflammatory pathways in ECP transgenic T cells. Remarkably, adoptively transferred ECP-containing exosomes stimulated serum levels of IFN-γ and autoantibodies in the recipient mice. The transferred exosomes infiltrated into multiple tissues of the recipient mice, resulting in hepatitis, nephritis, and arthritis.

Conclusions: ECP overexpression in T cells or T-cell-derived exosomes may be a biomarker and pathogenic factor for human SLE nephritis, hepatitis, and arthritis….detail

Cell Reports. November 23, 2021. 37:110016. Dr. Cheng-Yuan Kaoicon-achi
Identification of a gut microbiota member that ameliorates DSS-induced colitis in intestinal barrier enhanced Dusp6-deficient mice.
Strengthening the gut epithelial barrier is a potential strategy for management of gut microbiota-associated illnesses. Here, we demonstrate that dual-specificity phosphatase 6 (Dusp6) knockout enhances baseline colon barrier integrity and ameliorates dextran sulfate sodium (DSS)-induced colonic injury. DUSP6 mutation in Caco-2 cells enhances the epithelial feature and increases mitochondrial oxygen consumption, accompanied by altered glucose metabolism and decreased glycolysis. We find that Dusp6-knockout mice are more resistant to DSS-induced dysbiosis, and the cohousing and fecal microbiota transplantation experiments show that the gut/fecal microbiota derived from Dusp6-knockout mice also confers protection against colitis. Further culturomics and mono-colonialization experiments show that one gut microbiota member in the genus Duncaniella confers host protection from DSS-induced injury. We identify Dusp6 deficiency as beneficial for shaping the gut microbiota eubiosis necessary to protect against gut barrier-related diseases….detail
icon-achiTheranostics. Oct 25, 2021. 11: 9953-9966. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
BPI overexpression suppresses Treg differentiation and induces exosome-mediated inflammation in systemic lupus erythematosus.
Background: Serum-derived exosomes are correlated with disease severity of human systemic lupus erythematosus (SLE). The proteins in the T-cell-derived exosomes from SLE patients could contribute to inflammation.

Methods: We characterized proteins of T cell-derived exosomes from SLE patients and healthy controls by proteomics. To study the potential pathogenic role of the identified exosomal protein, we generated and characterized T-cell-specific transgenic mice that overexpressed the identified protein in T cells using immunohistochemistry, immunoblotting, and single-cell RNA sequencing.

Results: We identified an overexpressed protein, bactericidal/permeability-increasing protein (BPI), in SLE T cells and T-cell-derived exosomes. T-cell-specific BPI transgenic (Lck-BPI Tg) mice showed multi-tissue inflammation with early induction of serum IL-1β levels, as well as serum triglyceride and creatinine levels. Interestingly, exosomes of Lck-BPI Tg T cells stimulated IL-1β expression of wild-type recipient macrophages. Remarkably, adoptive transfer of BPI-containing exosomes increased serum IL-1β and autoantibody levels in recipient mice. The transferred exosomes infiltrated into multiple tissues of recipient mice, resulting in hepatitis, nephritis, and arthritis. ScRNA-seq showed that Lck-BPI Tg T cells displayed a decrease of Treg population, which was concomitant with ZFP36L2 upregulation and Helios downregulation. Furthermore, in vitro Treg differentiation was reduced by BPI transgene and enhanced by BPI knockout.

Conclusions: BPI is a negative regulator of Treg differentiation. BPI overexpression in T-cell-derived exosomes or peripheral blood T cells may be a biomarker and pathogenic factor for human SLE nephritis, hepatitis, and arthritis….detail

J. Immunol. Sep 15, 2020. 205:1644-1652. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuangicon-achi
 DUSP11 Attenuates Lipopolysaccharide-Induced Macrophage Activation by Targeting TAK1.
Dual-specificity phosphatase 11 (DUSP11, also named as PIR1) is a member of the atypical DUSP protein tyrosine phosphatase family. DUSP11 is only known to be an RNA phosphatase that regulates noncoding RNA stability. To date, the role of DUSP11 in immune cell signaling and immune responses remains unknown. In this study, we generated and characterized the immune cell functions of DUSP11-deficient mice. We identified TGF-β-activated kinase 1 (TAK1) as a DUSP11-targeted protein. DUSP11 interacted directly with TAK1, and the DUSP11-TAK1 interaction was enhanced by LPS stimulation in bone marrow-derived macrophages. DUSP11 deficiency enhanced the LPS-induced TAK1 phosphorylation and cytokine production in bone marrow-derived macrophages. Furthermore, DUSP11-deficient mice were more susceptible to LPS-induced endotoxic shock. The LPS-induced serum levels of IL-1β, TNF-α, and IL-6 were significantly elevated in DUSP11-deficient mice compared with those of wild-type mice. The data indicate that DUSP11 inhibits LPS-induced macrophage activation by targeting TAK1….detail
icon-achiFASEB J. 2019 Dec. 33:14653-14667. Dr. Wen-Jye Lin
DUSP22 suppresses prostate cancer proliferation by targeting the EGFR/AR axis.
Dual-specificity phosphatases (DUSPs) regulate the activity of various downstream kinases through serine or threonine or tyrosine dephosphorylation. Loss of function and aberrant expression of DUSPs has been implicated in cancer progression and poor survival, yet the function of DUSP22 in prostate cancer (PCa) cells is not clear. Gene Expression Omnibus and cBioPortal microarray database analyses showed that DUSP22 expression was lower in PCa tissues than normal prostate tissues, and altered DUSP22 expression was associated with shorter progression-free and disease-free survival of patients with PCa. Exogenous DUSP22 expression in LNCaP, PC3, and C4-2B PCa cells inhibited cellular proliferation and colony formation, supporting a growth inhibitory role for DUSP22 in PCa cells. DUSP22 expression significantly attenuated epidermal growth factor (EGF) receptor (EGFR) and its downstream ERK1/2 signaling by dephosphorylation. However, DUSP22 failed to suppress the growth of CWR22Rv1 and DU145 cells with elevated phosphorylated (p-)ERK1/2 levels. A serine-to-alanine mutation at position 58, a potential ERK1/2-targeted phosphorylation site in DUSP22, was sufficient to suppress growth of CWR22Rv1 cells with elevated p-ERK1/2 levels, suggesting a mutually antagonistic relationship between DUSP22 and ERK1/2 dependent on phosphorylation status. We showed that DUSP22 can suppress prostate-specific antigen gene expression through phosphatase-dependent pathways, suggesting that DUSP22 is an important regulator of the androgen receptor (AR) in PCa cells. Mechanistically, DUSP22 can interact with AR as a regulatory partner and interfere with EGF-induced AR phosphorylation at Tyr534, suggesting that DUSP22 serves as a crucial suppressor of both EGFR and AR-dependent signaling in PCa cells via dephosphorylation. Our findings indicate that loss of function of DUSP22 in PCa cells leads to aberrant activation of both EGFR-ERKs and AR signaling and ultimately progression of PCa, supporting the potential for novel therapeutic design of harnessing DUSP22 in the treatment of PCa.-Lin, H.-P., Ho, H.-M., Chang, C.-W., Yeh, S.-D., Su, Y.-W., Tan, T.-H., Lin, W.-J. DUSP22 suppresses prostate cancer proliferation by targeting the EGFR-AR axis….detail
icon-achiCancer Research. 2019 Oct. DOI: 10.1158/0008-5472.  Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
MAP4K3/GLK promotes lung cancer metastasis by phosphorylating and activating IQGAP1.
Overexpression of the serine/threonine kinase GLK/MAP4K3 in human lung cancer is associated with poor prognosis and recurrence, however, the role of GLK in cancer recurrence remains unclear. Here, we report that transgenic GLK promotes tumor metastasis and cell migration through the scaffold protein IQ motif-containing GTPase-activating protein 1(IQGAP1). GLK transgenic mice displayed enhanced distant metastasis. IQGAP1 was identified as a GLK-interacting protein; two proline-rich regions of GLK and the WW domain of IQGAP1 mediated this interaction. GLK and IQGAP1 colocalized at the leading edge including filopodia and lamellipodia of migrating cells. GLK directly phosphorylated IQGAP1 at Ser-480 enhancing Cdc42 activation and subsequent cell migration. GLK-induced cell migration and lung cancer metastasis were abolished by IQGAP1 depletion. Consistently, human NSCLC patient tissues displayed increased phospho-IQGAP1, which correlated with poor survival. Collectively, GLK promotes lung cancer metastasis by binding to, phosphorylating, and activating IQGAP1. SIGNIFICANCE: These findings show the critical role of the GLK-IQGAP cascade in cell migration and tumor metastasis, suggesting it as a potential biomarker and therapeutic target for lung cancer recurrence….detail
icon-achiFASEB Journal. 2019 August. 33:11469-11480. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
 AhR-RORγt complex is a therapeutic target for MAP4K3/GLKhighIL-17Ahigh subpopulation of systemic lupus erythematosus.
The cytokine IL-17A plays critical roles in the pathogenesis of autoimmune diseases. The frequencies of MAP kinase kinase kinase kinase 3 [also named germinal center kinase-like kinase (GLK)]-overexpressing T cells are correlated with disease severity of systemic lupus erythematosus (SLE). T-cell-specific GLK-transgenic mice develop spontaneous autoimmune responses through IL-17A. GLK signaling selectively stimulates IL-17A production in murine T cells through inducing aryl hydrocarbon receptor (AhR)-retinoic acid receptor-related orphan nuclear receptor-γt (ROR-γt) complex formation. Here, we investigated whether GLK-induced AhR-ROR-γt complex in T cells is a therapeutic target for human SLE. The population of GLK+IL-17A+ T cells was enhanced in the peripheral blood from patients with SLE compared with that of healthy controls using flow cytometry. The receiver operating characteristic curve analysis showed that increased GLK+IL-17A+ T-cell population in peripheral blood reflected an active stage of SLE. In addition, peripheral blood T cells from patients with SLE displayed induction of ROR-γt phosphorylation and the AhR-ROR-γt (and AhR-phosphorylated ROR-γt) complex. Moreover, we identified a small-molecule inhibitor, verteporfin, that inhibited GLK kinase activity and AhR-ROR-γt interaction. The small-molecule inhibitor verteporfin suppressed the disease severity in autoimmune mouse models and IL-17A production in T cells from patients with SLE. Collectively, the GLK-induced AhR-ROR-γt (and AhR-phosphorylated ROR-γt) complex is a therapeutic target for the GLKhighIL-17Ahigh subpopulation of human patients with SLE.-Chuang, H.-C., Chen, Y.-M., Chen, M.-H., Hung, W.-T., Yang, H.-Y., Tseng, Y.-H., Tan, T.-H. AhR-ROR-γt complex is a therapeutic target for MAP4K3/GLKhighIL-17Ahigh subpopulation of systemic lupus erythematosus….detail
Cell Stem Cell. 2019 April. 24:579-591. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuangicon-achi
MAP4K4 inhibition promotes survival of human stem cell-derived cardiomyocytes and reduces Infarct size in vivo.
Heart disease is a paramount cause of global death and disability. Although cardiomyocyte death plays a causal role and its suppression would be logical, no clinical counter-measures target the responsible intracellular pathways. Therapeutic progress has been hampered by lack of preclinical human validation. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is activated in failing human hearts and relevant rodent models. Using human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) and MAP4K4 gene silencing, we demonstrate that death induced by oxidative stress requires MAP4K4. Consequently, we devised a small-molecule inhibitor, DMX-5804, that rescues cell survival, mitochondrial function, and calcium cycling in hiPSC-CMs. As proof of principle that drug discovery in hiPSC-CMs may predict efficacy in vivo, DMX-5804 reduces ischemia-reperfusion injury in mice by more than 50%. We implicate MAP4K4 as a well-posed target toward suppressing human cardiac cell death and highlight the utility of hiPSC-CMs in drug discovery to enhance cardiomyocyte survival….detail
icon-achiCell Death & Differentiation. 2018. Sep. Dr. Yu-Wen Su
PP4 deficiency leads to DNA replication stress that impairs immunoglobulin class switch efficiency.
The serine/threonine phosphatase PP4 has been implicated in DNA damage repair and cell cycle regulation through its dephosphorylation of specific substrates. We previously showed that PP4 is required for mouse B cell development, germinal center (GC) formation and immunoglobulin (Ig) class switch recombination (CSR). Here, we investigate the mechanisms underlying this requirement and demonstrate that murine PP4-deficient B lymphocytes have a defect in cell proliferation. Strikingly, the DNA damage response pathway that involves ATM/p53 and is linked to cell cycle arrest and impaired cell survival is strongly induced in these mutant B cells. In response to LPS + IL-4, stimuli that trigger IgG1 production, these PP4-deficient B cells show inefficient phosphorylation of ATR, leading to reduced retention of γH2AX-NBS1 complexes at sites of DNA damage, and compromised switching to IgG1. However, beyond the cell proliferation phase, conditional deletion of PP4 under the control of AID/cre completely restores normal IgG1 production in mutant B cell cultures. In vivo, co-deletion of PP4 and p53 by AID/cre partially rescues switching to IgG1 in B cells of mice immunized with TNP-KLH. Our findings establish that PP4 is indispensable for preventing DNA replication stress that could interfere with CSR, thereby promoting antibody switching during the humoral immune response….detail
icon-achiScience Advances. 2018 Sep. 4:eaat5401. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
GLK-IKKβ signaling induces dimerization and translocation of the AhR-RORγt complex in IL-17A induction and autoimmune disease
Retinoic-acid-receptor-related orphan nuclear receptor γt (RORγt) controls the transcription of interleukin-17A (IL-17A), which plays critical roles in the pathogenesis of autoimmune diseases. Severity of several human autoimmune diseases is correlated with frequencies of germinal center kinase-like kinase (GLK) (also known as MAP4K3)-overexpressing T cells; however, the mechanism of GLK overexpression-induced autoimmunity remains unclear. We report the signal transduction converging on aryl hydrocarbon receptor (AhR)-RORγt interaction to activate transcription of the IL-17A gene in T cells. T cell-specific GLK transgenic mice spontaneously developed autoimmune diseases with selective induction of IL-17A in T cells. In GLK transgenic T cells, protein kinase Cθ (PKCθ) phosphorylated AhR at Ser36 and induced AhR nuclear translocation. AhR also interacted with RORγt and transported RORγt into the nucleus. IKKβ (inhibitor of nuclear factor κB kinase β)-mediated RORγt Ser489 phosphorylation induced the AhR-RORγt interaction. T cell receptor (TCR) signaling also induced the novel RORγt phosphorylation and subsequent AhR-RORγt interaction. Collectively, TCR signaling or GLK overexpression induces IL-17Atranscription through the IKKβ-mediated RORγt phosphorylation and the AhR-RORγt interaction in T cells. Our findings suggest that inhibitors of GLK or the AhR-RORγt complex could be used as IL-17A-blocking agents for IL-17A-mediated autoimmune diseases...detail
icon-achiPNAS. 2018 Aug. Dr. Yu-Wen Su
DUSP6 mediates T cell receptor-engaged glycolysis and restrains TFH cell differentiation.
Activated T cells undergo metabolic reprogramming and effector-cell differentiation but the factors involved are unclear. Utilizing mice lacking DUSP6 (DUSP6/), we show that this phosphatase regulates T cell receptor (TCR) signaling to influence follicular helper T (TFH) cell differentiation and T cell metabolism. In vitro, DUSP6/ CD4+ TFH cells produced elevated IL-21. In vivo, TFHcells were increased in DUSP6/ mice and in transgenic OTII-DUSP6/ mice at steady state. After immunization, DUSP6/ and OTII-DUSP6/ mice generated more TFH cells and produced more antigen-specific IgG2 than controls. Activated DUSP6/ T cells showed enhanced JNK and p38 phosphorylation but impaired glycolysis. JNK or p38 inhibitors significantly reduced IL-21 production but did not restore glycolysis. TCR-stimulated DUSP6/ T cells could not induce phosphofructokinase activity and relied on glucose-independent fueling of mitochondrial respiration. Upon CD28 costimulation, activated DUSP6/ T cells did not undergo the metabolic commitment to glycolysis pathway to maintain viability. Unexpectedly, inhibition of fatty acid oxidation drastically lowered IL-21 production in DUSP6/ TFH cells. Our findings suggest that DUSP6 connects TCR signaling to activation-induced metabolic commitment toward glycolysis and restrains TFH cell differentiation via inhibiting IL-21 production….detail
Oncogene. July 23, 2018. doi: 10.1038/s41388-018-0411-0. Dr. Tsung-Hsien Chuangicon-achi
USP17 mediates macrophage-promoted inflammation and stemness in lung cancer cells by regulating TRAF2/TRAF3 complex formation.
Macrophage accumulation and inflammation in the lung owing to stresses and diseases is a cause of lung cancer development. However, molecular mechanisms underlying the interaction between macrophages and cancer cells, which drive inflammation and stemness in cancers, are poorly understood. In this study, we investigated the expression of ubiquitin-specific peptidase 17 (USP17) in lung cancers, and role of elevated USP17 in the interaction between macrophages and lung cancer cells. USP17 expression in lung cancers was associated with poor prognosis, macrophage, and inflammatory marker expressions. Macrophages promoted USP17 expression in cancer cells. TNFR-associated factor (TRAF) 2-binding and TRAF3-binding motifs were identified in USP17, through which it interacted with and disrupted the TRAF2/TRAF3 complex. This stabilized its client proteins, enhanced inflammation and stemness in cancer cells, and promoted macrophage recruitment. In different animal studies, co-injection of macrophages with cancer cells promoted USP17 expression in tumors and tumor growth. Conversely, depletion of macrophages in host animals by clodronate liposomes reduced USP17 expression and tumor growth. In addition, overexpression of USP17 in cancer cells promoted tumor growth and inflammation-associated and stemness-associated gene expressions in tumors. These results suggested that USP17 drives a positive-feedback interaction between macrophages and cancer cells to enhance inflammation and stemness in cancer cells, and promotes lung cancer growth….detail
icon-achiFASEB Journal. 2018 Jun. Dr. Tse-Hua Tan and Dr. Huai-Chia Chuang
Induction of DUSP14 ubiquitination by PRMT5-mediated arginine methylation.
Dual-specificity phosphatase (DUSP)14 (also known as MAP-kinase phosphatase 6) inhibits T-cell receptor (TCR) signaling and T-cell-mediated immune responses by inactivation of the TGF-β activated kinase 1 binding protein (TAB1)-TGF-β activated kinase 1 (TAK1) complex and ERK. DUSP14 phosphatase activity is induced by the E3 ligase TNF receptor associated factor (TRAF)2-mediated Lys63-linked ubiquitination. Here we report an interaction between DUSP14 and Protein arginine methyltransferase (PRMT)5 by proximity ligation assay; similarly, DUSP14 directly interacted with TAB1 but not TAK1. DUSP14 is methylated by PRMT5 at arginine 17, 38, and 45 residues. The DUSP14 triple-methylation mutant was impaired in PRMT5-mediated arginine methylation, TRAF2-mediated lysine ubiquitination, and DUSP14 phosphatase activity. Consistently, DUSP14 methylation, TRAF2 binding, and DUSP14 ubiquitination were attenuated by PRMT5 short hairpin RNA knockdown. Furthermore, DUSP14 was inducibly interacted with PRMT5 and was methylated during TCR signaling in T cells. Together, these findings reveal a novel regulatory mechanism of DUSP14 by which PRMT5-mediated arginine methylation may sequentially stimulate TRAF2-mediated DUSP14 ubiquitination and phosphatase activity, leading to inhibition of TCR signaling.-Yang, C.-Y., Chiu, L.-L., Chang, C.-C., Chuang, H.-C., Tan, T.-H. Induction of DUSP14 ubiquitination by PRMT5-mediated arginine methylation…..detail
icon-achiOncogene. 2017 Nov. 36:6509-6517. Dr. Tse-Hua Tan and Dr. Yi-Rong Chen
Deficiency in VHR/DUSP3, a suppressor of focal adhesion kinase, reveals its role in regulating cell adhesion and migration.
Vaccinia H1-related phosphatase (VHR/DUSP3) is a member of the dual-specificity phosphatase family. Deregulation of VHR is observed in various malignant diseases. We identified focal adhesion kinase (FAK) as a VHR-interacting molecule. Over-expression of VHR decreased tyrosine phosphorylation of FAK and decreasing VHR promoted FAK tyrosine phosphorylation. In vitro assays proved that recombinant VHR directly dephosphorylated FAK and paxillin. VHR-knockout mice did not have obvious abnormality; however, VHR-knockout cells showed decreased expression of integrins and FAK but stronger FAK and paxillin phosphorylation upon attachment to fibronectin. Additionally, VHR-knockout fibroblast and lung epithelial cells had elevated ligand-induced epidermal growth factor receptor (EGFR) phosphorylation. Inducible expression of VHR suppressed directional cell migration, and VHR deficiency resulted in a higher cell migratory ability. VHR-knockout cells have stronger FAK phosphorylation in cell adhesions, long-lasting trailing ends and slower turnover of focal adhesions. These collective data indicate that VHR is a FAK phosphatase and participates in regulating the formation and disassembly of focal adhesions….detail
icon-achiNature Microbiology. 2016 Nov. 2:16220. Dr. Cheng-Yuan Kao
Deficiency of dual-specificity phosphatase 6 increases resistance to diet-induced obesity via regulating commensal response.
The gut microbiota plays profound roles in host metabolism and the inflammatory response associated with the development of obesity. Dusp6-deficient mice have been shown to be resistant to diet-induced obesity, but the mechanism behind this remains unclear. 16S ribosomal RNA gene analysis demonstrated that dusp6-deficient mice harbour unique gut microbiota with resistance to diet-induced-obesity-mediated alteration of the gut microbiome. Using a germ-free mouse model, we found that faecal/gut microbiota derived from dusp6-deficient mice significantly increased energy expenditure and reduced weight gain in recipient wild-type mice fed on a high-fat diet. On analysis of the intestinal transcriptome of dusp6-deficient mice, we found that dusp6 deficiency mainly induced biological processes involved in metabolism and the extracellular matrix, particularly the peroxisome proliferator-activated receptor gamma (Pparγ) pathway and tight-junction genes. Furthermore, dusp6-deficient mice have a high-fat-diet-specific transcriptomic response to reverse the expression of genes associated with intestinal barrier functions and mucosal immunity involved in microbiome homeostasis. This study demonstrates that dusp6 deficiency is a strong genetic factor shaping gut microbiota, and that it confers obesity protection by ameliorating the gut microbiota response to diet-mediated stress…detail
icon-achiCell Death and Differentiation. 2016 May. 23:841. Dr. Tsung-Hsien Chuang
Downregulation of COMMD1 by miR-205 promotes a positive feedback loop for amplifying inflammatory- and stemness-associated properties of cancer cells.
Sustained activation of nuclear factor-kappaB (NF-kappaB) in cancer cells has been shown to promote inflammation, expansion of cancer stem cell (CSC) population, and tumor development. In contrast, recent studies reveal that CSCs exhibit increased inflammation due to constitutive NF-kappaB activation; however, the underlying molecular mechanism remains unclear. In the present study, the analysis of microarray data revealed upregulation of NF-kappaB-regulated pro-inflammatory genes and downregulation of copper metabolism MURR1 domain-containing 1 (COMMD1) during the enrichment for stemness in SAS head and neck squamous-cell carcinoma (HNSCC) cells. The 3′-UTR of COMMD1 mRNA contains microRNA (miR)-205 target site. Parallel studies with HNSCC and NSCLC cells indicated that miR-205 is upregulated upon NF-kappaB activation and suppresses COMMD1 expression in stemness-enriched cancer cells. COMMD1 negatively regulates the inflammatory responses induced by TLR agonists, IL-1beta, and TNF-alpha by targeting RelA for degradation. The shRNA-mediated downregulation of COMMD1 in cancer cells enhanced inflammatory response, generating favorable conditions for macrophage recruitment. In addition, genes associated with stemness were also upregulated in these cells, which exhibited increased potential for anchorage-independent growth. Furthermore, COMMD1 downregulation promoted in vivo tumorigenesis and tumor growth, and tumors derived from COMMD1-knockdown cells displayed elevated level of NF-kappaB activation, increased expression of inflammatory- and stemness-associated genes, and contain expanded population of tumor-associated leukocytes and stemness-enriched cancer cells. These results suggest that COMMD1 downregulation by miR-205 promotes tumor development by modulating a positive feedback loop that amplifies inflammatory- and stemness-associated properties of cancer cells…detail
icon-achiJournal of Immunology.2015 Oct. 195:3912. Dr. Tsung-Hsien Chuang
Identification of Thiostrepton as a Novel Inhibitor for Psoriasis-like Inflammation Induced by TLR7-9.
J Immunol-2015-Lai-3912-21 9Activation of TLR7-9 has been linked to the pathogenesis of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and psoriasis. Thus, therapeutic applications of antagonists of these TLRs for such disorders are being investigated. Bortezomib (Velcade) is a proteasome inhibitor known to suppress activation of these TLRs. To identify novel TLR7-9 inhibitors, we searched the Gene Expression Omnibus database for gene expression profiles of bortezomib-treated cells. These profiles were then used to screen the Connectivity Map database for chemical compounds with similar functions as bortezomib. A natural antibiotic, thiostrepton, was identified for study. Similar to bortezomib,thiostrepton effectively inhibits TLR7-9 activation in cell-based assays and in dendritic cells. In contrast to bortezomib, thiostrepton does not inhibit NF-κB activation induced by TNF-α, IL-1, and other TLRs, and it is less cytotoxic to dendritic cells. Thiostrepton inhibits TLR9 localization in endosomes for activation via two mechanisms, which distinguish it from currently used TLR7-9 inhibitors. One mechanism is similar to the proteasome inhibitory function of bortezomib, whereas the other is through inhibition of endosomal acidification. Accordingly, in different animal models, thiostrepton attenuated LL37- and imiquimod-induced psoriasis-like inflammation. These results indicated that thiostrepton is a novel TLR7-9inhibitor, and compared with bortezomib, its inhibitory effect is more specific to these TLRs, suggesting the potential therapeutic applications ofthiostrepton on immunologic disorders elicited by inappropriate activation of TLR7-9…detail
icon-achiNat. Commun. 2014 Aug. 5:4602.  Dr. Tse-Hua Tan
HGK/MAP4K4 deficiency induces TRAF2 stabilization and Th17 differentiation leading to insulin resistance.
ncomms5602-f10Proinflammatory cytokines play important roles in insulin resistance. Here we report that mice with a T-cell-specific conditional knockout of HGK (T-HGK cKO) develop systemic inflammation and insulin resistance. This condition is ameliorated by either IL-6 or IL-17 neutralization. HGK directly phosphorylates TRAF2, leading to its lysosomal degradation and subsequent inhibition of IL-6 production. IL-6-overproducing HGK-deficient T cells accumulate in adipose tissue and further differentiate into IL-6/IL-17 double-positive cells. Moreover, CCL20 neutralization or CCR6 deficiency reduces the Th17 population or insulin resistance in T-HGK cKO mice. In addition, leptin receptor deficiency in T cells inhibits Th17 differentiation and improves the insulin sensitivity in T-HGK cKO mice, which suggests that leptin cooperates with IL-6 to promote Th17 differentiation. Thus, HGK deficiency induces TRAF2/IL-6 upregulation, leading to IL-6/leptin-induced Th17 differentiation in adipose tissue and subsequent insulin resistance. These findings provide insight into the reciprocal regulation between the immune system and the metabolism…detail
icon-achiNat. Commun. 2014 Apr. 5:3618.  Dr. Tse-Hua Tan
The phosphatase JKAP/DUSP22 inhibits T-cell receptor signalling and autoimmunity by inactivating Lck.
ncomms4618-f9JNK pathway-associated phosphatase (JKAP, also known as DUSP22 or JSP-1) is a JNK activator. The in vivo role of JKAP in immune regulation remains unclear. Here we report that JKAP directly inactivates Lck by dephosphorylating tyrosine-394 residue during T-cell receptor (TCR) signalling. JKAP-knockout T cells display enhanced cell proliferation and cytokine production. JKAP-knockout mice show enhanced T-cell-mediated immune responses and are more susceptible to experimental autoimmune encephalomyelitis (EAE). In addition, the recipient mice that are adoptively transferred with JKAP-knockout T cells show exacerbated EAE symptoms. Aged JKAP-knockout mice spontaneously develop inflammation and autoimmunity. Thus, our results indicate that JKAP is an important phosphatase that inactivates Lck in the TCR signalling turn-off stage, leading to suppression of T-cell-mediated immunity and autoimmunity.…detail
icon-achiJ. Immunol. 2014 Feb. 192:1547-57. Dr. Tse-Hua Tan
Dual-specificity phosphatase 14 (DUSP14/MKP6) negatively regulates TCR signaling by inhibiting TAB1.
TAN-J OF IMMU2014T cell activation is dependent upon phosphorylation of MAPKs, which play a critical role in the regulation of immune responses. Dual-specificity phosphatase 14 (DUSP14; also known as MKP6) is classified as a MAPK phosphatase. The in vivo functions of DUSP14 remain unclear. Thus, we generated DUSP14-deficient mice and characterized the roles of DUSP14 in T cell activation and immune responses. DUSP14 deficiency in T cells resulted in enhanced T cell proliferation and increased cytokine production upon T cell activation. DUSP14 directly interacted with TGF-β-activated kinase 1 (TAK1)-binding protein 1 (TAB1) and dephosphorylated TAB1 at Ser(438), leading to TAB1-TAK1 complex inactivation in T cells. The phosphorylation levels of the TAB1-TAK1 complex and its downstream molecules, including JNK and IκB kinase, were enhanced in DUSP14-deficient T cells upon stimulation. The enhanced JNK and IκB kinase activation in DUSP14-deficient T cells was attenuated by TAB1 short hairpin RNA knockdown. Consistent with that, DUSP14-deficient mice exhibited enhanced immune responses and were more susceptible to experimental autoimmune encephalomyelitis induction. Thus, DUSP14 negatively regulates TCR signaling and immune responses by inhibiting TAB1 activation…detail
icon-achiPNAS. 2013 Dec. 110:20711-6. Dr. Tsung-Hsien Chuang
Toll-like receptor 9 and 21 have different ligand recognition profiles and cooperatively mediate activity of CpG-oligodeoxynucleotides in zebrafish.
Chuang-PNAS2013CpG-oligodeoxynucleotides (CpG-ODNs) are potent immune stimuli currently under investigation as antimicrobial agents for different species. Toll-like receptor (TLR) 9 and TLR21 are the cellular receptors of CpG-ODN in mammals and chickens, respectively. The avian genomes lack TLR9, whereas mammalian genomes lack TLR21. Although fish contain both of these genes, the biological functions of fish TLR9 and TLR21 have not been investigated previously. In this study, we comparatively investigated zebrafish TLR9 (zebTLR9) and TLR21 (zebTLR21). The two TLRs have similar expression profiles in zebrafish. They are expressed during early development stages and are preferentially expressed in innate immune function-related organs in adult fish. Results from cell-based activation assays indicate that these two zebrafish TLRs are functional, responding to CpG-ODN but not to other TLR ligands. zebTLR9 broadly recognized CpG-ODN with different CpG motifs, but CpG-ODN with GACGTT or AACGTT had better activity to this TLR. In contrast, zebTLR21 responded preferentially to CpG-ODN with GTCGTT motifs. The distinctive ligand recognition profiles of these two TLRs were determined by their ectodomains. Activation of these two TLRs by CpG-ODN occurred inside the cells and was modulated by UNC93B1. The biological functions of these two TLRs were further investigated. The CpG-ODNs that activate both zebTLR9 and zebTLR21 were more potent than others that activate only zebTLR9 in the activation of cytokine productions and were more bactericidal in zebrafish. These results suggest that zebTLR9 and zebTLR21 cooperatively mediate the antimicrobial activities of CpG-ODN. Overall, this study provides a molecular basis for the activities of CpG-ODN in fish…detail
icon-achiArthritis Rheum. 2013 Oct. 65:2573-82. Dr. Tse-Hua Tan
Germinal center kinase-like kinase overexpression in T cells as a novel biomarker in rheumatoid arthritis.
TAN-ARTHRITIS2013Objective – Germinal center kinase–like kinase (GLK; also called MAPKKKK-3) activates protein kinase Cθ (PKCθ) during T cell activation and controls autoimmunity in lupus patients. Intracellular kinases are involved in the pathogenesis of rheumatoid arthritis (RA). We undertook this study to determine the role of GLK in RA. Methods – The severity of collagen-induced arthritis (CIA) was studied in GLK-deficient mice. Expression levels of GLK from RA patients were determined by Western blotting, flow cytometry, real-time polymerase chain reaction, and immunohistochemical staining. Localization of GLK in T cells was identified by confocal microscopy. RA disease activity was assessed using the Disease Activity Score in 28 joints…detail
icon-achiJ. Biol. Chem. 2012 Oct. 287:34091-100. Dr. Tse-Hua Tan
Attenuation of T cell receptor signaling by serine phosphorylation-mediated lysine 30 ubiquitination of SLP-76 protein.
TAN-JBC2012SLP-76 (SH2 domain-containing leukocyte protein of 76 kDa) is an adaptor protein that is essential for T cell development and T cell receptor (TCR) signaling activation. Previous studies have identified an important negative feedback regulation of SLP-76 by HPK1 (hematopoietic progenitor kinase 1; MAP4K1)-induced Ser-376 phosphorylation. Ser-376 phosphorylation of SLP-76 mediates 14-3-3 binding, resulting in the attenuation of SLP-76 activation and downstream signaling; however, the underlying mechanism of this action remains unknown. Here, we report that phosphorylated SLP-76 is ubiquitinated and targeted for proteasomal degradation during TCR signaling. SLP-76 ubiquitination is mediated by Ser-376 phosphorylation. Furthermore, Lys-30 is identified as a ubiquitination site of SLP-76. Loss of Lys-30 ubiquitination of SLP-76 results in enhanced anti-CD3 antibody-induced ERK and JNK activation. These results reveal a novel regulation mechanism of SLP-76 by ubiquitination and proteasomal degradation of activated SLP-76, which is mediated by Ser-376 phosphorylation, leading to down-regulation of TCR signaling…detail
icon-achiBMC Med. 2012 Aug. 10:84.  Dr. Tse-Hua Tan
Germinal center kinase-like kinase (GLK/MAP4K3) expression is increased in adult-onset Still’s disease and may act as an activity marker
TAN-BMC2012Background – Germinal center kinase-like kinase (GLK, also termed MAP4K3), a member of the MAP4K family, may regulate gene transcription, apoptosis and immune inflammation in response to extracellular signals. The enhanced expression of GLK has been shown to correspond with disease severity in patients with systemic lupus erythematosus. We investigated the role of GLK in the pathogenesis of adult-onset Still’s disease, which shares some similar clinical characteristics with systemic lupus erythematosus. Methods – The frequencies of circulating GLK-expressing T-cells in 24 patients with active adult-onset Still’s disease and 12 healthy controls were determined by flow cytometry analysis. The expression levels of GLK proteins and transcripts were evaluated in peripheral blood mononuclear cells by immunoblotting and quantitative PCR. Serum levels of T helper (Th)17-related cytokines, including IL-1β, IL-6, IL-17 and TNF-α, were measured by ELISA…detail
icon-achiJ. Biol. Chem. 2012 Feb. 287:11037-48. Dr. Tse-Hua Tan
Downregulation of B-cell receptor signaling by hematopoietic progenitor kinase 1 (HPK1)-mediated phosphorylation and ubiquitination of the activated BLNK
jbc.M111.310946.full 23Hematopoietic progenitor kinase 1 (HPK1) is a Ste20-like serine/threonine kinase that suppresses immune responses and autoimmunity. B-cell receptor (BCR) signaling activates HPK1 by inducing BLNK/HPK1 interaction. Whether HPK1 can reciprocally regulate BLNK during BCR signaling is unknown. Here we show that HPK1-deficient B cells display hyper-proliferation and hyper-activation of IKK and MAPKs (ERK, p38, and JNK) upon the ligation of BCR. HPK1 attenuates BCR-induced cell activation via inducing BLNK threonine152 phosphorylation, which mediates BLNK/14-3-3 binding. Furthermore, threonine152-phosphorylated BLNK is ubiquitinated at lysine37, 38 and 42 residues, leading to attenuation of MAPK and IKK activation in B cells during BCR signaling. These results reveal a novel negative feedback regulation of BCR signaling by HPK1-mediated phosphorylation, ubiquitination, and subsequent degradation of the activated BLNK…detail
icon-achiEur J Immunol. 2012 Feb. 42:476-88. Dr. Ching-Yu Huang / Dr. Tse-Hua Tan
DUSP4 deficiency enhances CD25 expression and CD4+ T-cell proliferation without impeding T-cell development.
476_ftp 6The differentiation and activation of T cells are critically modulated by MAP kinases, which are in turn feed-back regulated by dual-specificity phosphatases (DUSPs) to determine the duration and magnitude of MAP kinase activation. DUSP4 (also known as MKP2) is a MAP kinase-induced DUSP member that is dynamically expressed during thymocyte differentiation. We generated DUSP4-deficient mice to study the function of DUSP4 in T-cell development and activation. Our results show that thymocyte differentiation and activation-induced MAP kinase phosphorylation were comparable between DUSP4-deficient and WT mice. Interestingly, activated DUSP4-/- CD4+ T cells were hyperproliferative while DUSP4-/- CD8+ T cells proliferated normally. Further mechanistic studies suggested that the hyperproliferation of DUSP4-/- CD4+ T cells resulted from enhanced CD25 expression and IL-2 signaling through increased STAT5 phosphorylation…detail
icon-achiNat. Immunol. 2011 Nov.12:1113-8. Dr. Tse-Hua Tan / Dr. Ching-Yu Huang
GLK controls autoimmunity and NF-kB signaling by activating PKCθ in T cells.
 ni_2121-S101Protein kinase C-θ (PKC-θ) is required for activation of the transcription factor NF-κB induced by signaling via the T cell antigen receptor (TCR); however, the direct activator of PKC-θ is unknown. We report that the kinase GLK (MAP4K3) directly activated PKC-θ during TCR signaling. TCR signaling activated GLK by inducing its direct interaction with the upstream adaptor SLP-76. GLK-deficient mice had impaired immune responses and were resistant to experimental autoimmune encephalomyelitis. Consistent with that, people with systemic lupus erythematosus had considerable enhanced GLK expression and activation of PKC-θ and the kinase IKK in T cells, and the frequency of GLK-overexpressing T cells was directly correlated with disease severity. Thus, GLK is a direct activator of PKC-θ, and activation of GLK-PKC-θ-IKK could be used as new diagnostic biomarkers and therapeutic targets for systemic lupus erythematosus….detail
icon-achiFASEB J. 2011 Aug. 25:2700-10. Dr. Tsung-Hsien Chuang
Functional interaction of Hsp90 and Beclin 1 modulates Toll-like receptor-mediated autophagy.
Microsoft Word - Figures 022311.docAutophagy is one of the downstream effector mechanisms for elimination of intracellular microbes following activation of the Toll-like receptors (TLRs). Although the detailed molecular mechanism for this cellular process is still unclear, Beclin 1, a key molecule for autophagy, has been suggested to play a role. Heat shock protein 90 (Hsp90) is a molecular chaperone that regulates the stability of signaling proteins. Herein, we show that Hsp90 forms a complex with Beclin 1 through an evolutionarily conserved domain to maintain the stability of Beclin 1. In monocytic cells, geldanamycin (GA), an Hsp90 inhibitor, effectively promoted proteasomal degradation of Beclin 1 in a concentration-dependent (EC50 100 nM) and time-dependent (t50 2 h) manner. In contrast, KNK437/Hsp inhibitor I had no effect. Hsp90 specifically interacted with Beclin 1 but not with other adapter proteins in the TLR signalsome…detail
icon-achiPNAS. 2011 Nov. 108:18354-9.  Dr. Yu-wen Su
Crucial role for TNF receptor-associated factor 2(TRAF2) in regulating NFκB2 signaling that contributes to autoimmunity.
PNAS-18354_full 5(1)TNF receptor-associated factor 2 (TRAF2) is a key intracellular signaling mediator that acts downstream of not only TNFα but also various members of the TNFα superfamily. Here, we report that, despite their lack of TNFα signaling, TRAF2−/−TNFα−/− mice develop an inflammatory disorder characterized by autoantibody accumulation and organ infiltration by T cells with the phenotypes of activated, effector, and memory cells. RAG1−/− mice reconstituted with TRAF2−/−TNFα−/− bone marrow cells showed increased numbers of hyperactive T cells and rapidly developed progressive and eventually lethal inflammation. No inflammation was observed in RAG1−/− mice reconstituted with TRAF2−/−TNFα−/−T-cell receptor β−/− or TRAF2−/−TNFα−/−NFκB-induced kinase+/− bone marrow cells. The pathogenic TRAF2−/−TNFα−/− T cells showed constitutive NFκB2p52 activation and produced elevated levels of T-helper 1 and T-helper 17 cytokines…detail
J. Biol. Chem. 2010 Feb. 285:5472-8. Dr. Tse-Hua Tanicon-achi
JNK pathway-associated phosphatase dephosphorylates focal adhesion kinase and suppresses cell migration.
capture-20120222-171451JNK pathway-associated phosphatase (JKAP, also named DUSP22) is expressed in various tissues, indicating that JKAP may have an important biological function. We showed that JKAP localized in the actin filament-enriched region. Expression of JKAP reduced cell migration, whereas a JKAP mutant lacking catalytic activity promoted cell motility. JKAP efficiently removed tyrosine phosphorylation of several proteins. We have identified focal adhesion kinase (FAK) as a substrate of JKAP. Overexpression of JKAP, but not JKAP mutant lacking catalytic activity, decreased FAK phosphorylation at tyrosines 397, 576, and 577 in H1299 cells. Consistent with these results, decreasing JKAP expression by RNA interference promoted cell migration and Src-induced FAK phosphorylation. Taken together, this study identified a new role for JKAP in the modulation of FAK phosphorylation and cell motility…detail



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