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Jin K, Qiu S, Chen B, Zhang Z, Zhang C, Zhou X, Yang L, Ai J, Wei Q. DOK3 promotes proliferation and inhibits apoptosis of prostate cancer via the NF-κB signaling pathway. Chin Med J (Engl) 2023; 136:423-432. [PMID: 36867541 PMCID: PMC10106266 DOI: 10.1097/cm9.0000000000002251] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND DOK3 (Downstream of kinase 3) is involved primarily with immune cell infiltration. Recent research reported the role of DOK3 in tumor progression, with opposite effects in lung cancer and gliomas; however, its role in prostate cancer (PCa) remains elusive. This study aimed to explore the role of DOK3 in PCa and to determine the mechanisms involved. METHODS To investigate the functions and mechanisms of DOK3 in PCa, we performed bioinformatic and biofunctional analyses. Samples from patients with PCa were collected from West China Hospital, and 46 were selected for the final correlation analysis. A lentivirus-based short hairpin ribonucleic acid (shRNA) carrier was established for silencing DOK3. A series of experiments involving the cell counting kit-8, bromodeoxyuridine, and flow cytometry assays were performed to identify cell proliferation and apoptosis. Changes in biomarkers from the nuclear factor kappa B (NF-κB) signaling pathway were detected to verify the relationship between DOK3 and the NF-κB pathway. A subcutaneous xenograft mouse model was performed to examine phenotypes after knocking down DOK3 in vivo . Rescue experiments with DOK3 knockdown and NF-κB pathway activation were designed to verify regulating effects. RESULTS DOK3 was up-regulated in PCa cell lines and tissues. In addition, a high level of DOK3 was predictive of higher pathological stages and worse prognoses. Similar results were observed with PCa patient samples. After silencing DOK3 in PCa cell lines 22RV1 and PC3, cell proliferation was significantly inhibited while apoptosis was promoted. Gene set enrichment analysis revealed that DOK3 function was enriched in the NF-κB pathway. Mechanism experiments determined that knockdown of DOK3 suppressed activation of the NF-κB pathway, increased the expressions of B-cell lymphoma-2 like 11 (BIM) and B-cell lymphoma-2 associated X (BAX), and decreased the expression of phosphorylated-P65 and X-linked inhibitor of apoptosis (XIAP). In the rescue experiments, pharmacological activation of NF-κB by tumor necrosis factor-α (TNF-α) partially recovered cell proliferation after the knockdown of DOK3. CONCLUSION Our findings suggest that overexpression of DOK3 promotes PCa progression by activating the NF-κB signaling pathway.
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Affiliation(s)
- Kun Jin
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shi Qiu
- Center of Biomedical Big Data, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Bo Chen
- Department of Urology and Institute of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Zilong Zhang
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Chichen Zhang
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xianghong Zhou
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Lu Yang
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Jianzhong Ai
- Department of Urology and Institute of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Qiang Wei
- Department of Urology and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
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Jackson JT, Mulazzani E, Nutt SL, Masters SL. The role of PLCγ2 in immunological disorders, cancer, and neurodegeneration. J Biol Chem 2021; 297:100905. [PMID: 34157287 PMCID: PMC8318911 DOI: 10.1016/j.jbc.2021.100905] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylinositol-specific phospholipase Cγ2 (PLCγ2) is a critical signaling molecule activated downstream from a variety of cell surface receptors that contain an intracellular immunoreceptor tyrosine-based activation motif. These receptors recruit kinases such as Syk, BTK, and BLNK to phosphorylate and activate PLCγ2, which then generates 1D-myo-inositol 1,4,5-trisphosphate and diacylglycerol. These well-known second messengers are required for diverse membrane functionality including cellular proliferation, endocytosis, and calcium flux. As a result, PLCγ2 dysfunction is associated with a variety of diseases including cancer, neurodegeneration, and immune disorders. The diverse pathologies associated with PLCγ2 are exemplified by distinct genetic variants. Inherited mutations at this locus cause PLCγ2-associated antibody deficiency and immune dysregulation, in some cases with autoinflammation. Acquired mutations at this locus, which often arise as a result of BTK inhibition to treat chronic lymphocytic leukemia, result in constitutive downstream signaling and lymphocyte proliferation. Finally, a third group of PLCγ2 variants actually has a protective effect in a variety of neurodegenerative disorders, presumably by increased uptake and degradation of deleterious neurological aggregates. Therefore, manipulating PLCγ2 activity either up or down could have therapeutic benefit; however, we require a better understanding of the signaling pathways propagated by these variants before such clinical utility can be realized. Here, we review the signaling roles of PLCγ2 in hematopoietic cells to help understand the effect of mutations driving immune disorders and cancer and extrapolate from this to roles which may relate to protection against neurodegeneration.
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Affiliation(s)
- Jacob T Jackson
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Elisabeth Mulazzani
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Stephen L Nutt
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Seth L Masters
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou, Guangdong, China.
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3
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Gao WS, Qu YJ, Huai J, Wei H, Zhang Y, Yue SW. DOK3 is involved in microglial cell activation in neuropathic pain by interacting with GPR84. Aging (Albany NY) 2020; 13:389-410. [PMID: 33281117 PMCID: PMC7835011 DOI: 10.18632/aging.202144] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/09/2020] [Indexed: 01/12/2023]
Abstract
Adaptor molecule downstream of kinase-3 (DOK3) is a vital regulator of innate immune responses in macrophages and B cells, and G-protein-coupled receptor 84 (GPR84) is significant in mediating the biosynthesis and maintenance of inflammatory mediators that are induced by neuropathic pain in microglia. In the present study, we determined the role of DOK3 in activating microglia-induced neuropathic pain and investigated the underlying mechanisms associated with GPR84. We found that knockdown of DOK3 in microglial cells dramatically reduced the levels of inflammatory factors, and we uncovered a physical association between DOK3 and GPR84 in the induction of inflammatory responses. We also observed that neuropathic pain and inflammatory responses induced by chronic constriction injury (CCI) of the sciatic nerve or intrathecal injection of a GPR84 agonist were compromised in DOK3-/- mice in vivo. Finally, enforced expression of DOK3 provoked inflammatory responses, and administration of pregabalin relieved neuropathic pain via inhibition of DOK3 expression. In conclusion, DOK3 induced neuropathic pain in mice by interacting with GPR84 in microglia. We hypothesize that targeting the adaptor protein DOK3 may open new avenues for pharmaceutical approaches to the alleviation of neuropathic pain in the spinal cord.
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Affiliation(s)
- Wen-Shuang Gao
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yu-Juan Qu
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Juan Huai
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hui Wei
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yang Zhang
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Shou-Wei Yue
- Rehabilitation Center, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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4
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Loh JT, Teo JKH, Lim HH, Lam KP. Emerging Roles of Downstream of Kinase 3 in Cell Signaling. Front Immunol 2020; 11:566192. [PMID: 33133079 PMCID: PMC7550416 DOI: 10.3389/fimmu.2020.566192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/10/2020] [Indexed: 11/18/2022] Open
Abstract
Downstream of kinase (Dok) 3 is a member of the Dok family of adaptor proteins known to regulate signaling pathways downstream of various immunoreceptors. As Dok-3 lacks intrinsic catalytic activity, it functions primarily as a molecular scaffold to facilitate the nucleation of protein complexes in a regulated manner and hence, achieve specificity in directing signaling cascades. Since its discovery, considerable progress has been made toward defining the role of Dok-3 in limiting B cell-receptor signaling. Nonetheless, Dok-3 has since been implicated in the signaling of Toll-like and C-type lectin receptors. Emerging data further demonstrate that Dok-3 can act both as an activator and inhibitor, in lymphoid and non-lymphoid cell types, suggesting Dok-3 involvement in a plethora of signal transduction pathways. In this review, we will focus on the structure and expression profile of Dok-3 and highlight its role during signal transduction in B cells, innate cells as well as in bone and lung tissues.
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Affiliation(s)
- Jia Tong Loh
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - Joey Kay Hui Teo
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - Hong-Hwa Lim
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
| | - Kong-Peng Lam
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore, Singapore.,Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,School of Biological Sciences, College of Science, Nanyang Technological University, Singapore, Singapore
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5
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Interplay between HGAL and Grb2 proteins regulates B-cell receptor signaling. Blood Adv 2020; 3:2286-2297. [PMID: 31362927 DOI: 10.1182/bloodadvances.2018016162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 05/30/2019] [Indexed: 01/30/2023] Open
Abstract
Human germinal center (GC)-associated lymphoma (HGAL) is an adaptor protein expressed in GC B cells. HGAL regulates cell motility and B-cell receptor (BCR) signaling, processes that are central for the successful completion of the GC reaction. Herein, we demonstrate phosphorylation of HGAL by Syk and Lyn kinases at tyrosines Y80, Y86, Y106Y107, Y128, and Y148. The HGAL YEN motif (amino acids 107-109) is similar to the phosphopeptide motif pYXN used as a binding site to the growth factor receptor-bound protein 2 (Grb2). We demonstrate by biochemical and molecular methodologies that HGAL directly interacts with Grb2. Concordantly, microscopy studies demonstrate HGAL-Grb2 colocalization in the membrane central supramolecular activation clusters (cSMAC) following BCR activation. Mutation of the HGAL putative binding site to Grb2 abrogates the interaction between these proteins. Further, this HGAL mutant localizes exclusively in the peripheral SMAC and decreases the rate and intensity of BCR accumulation in the cSMAC. Furthermore, we demonstrate that Grb2, HGAL, and Syk interact in the same complex, but Grb2 does not modulate the effects of HGAL on Syk kinase activity. Overall, the interplay between the HGAL and Grb2 regulates the magnitude of BCR signaling and synapse formation.
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7
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The regulators of BCR signaling during B cell activation. BLOOD SCIENCE 2019; 1:119-129. [PMID: 35402811 PMCID: PMC8975005 DOI: 10.1097/bs9.0000000000000026] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 07/25/2019] [Indexed: 11/26/2022] Open
Abstract
B lymphocytes produce antibodies under the stimulation of specific antigens, thereby exerting an immune effect. B cells identify antigens by their surface B cell receptor (BCR), which upon stimulation, directs the cell to activate and differentiate into antibody generating plasma cells. Activation of B cells via their BCRs involves signaling pathways that are tightly controlled by various regulators. In this review, we will discuss three major BCR mediated signaling pathways (the PLC-γ2 pathway, PI3K pathway and MAPK pathway) and related regulators, which were roughly divided into positive, negative and mutual-balanced regulators, and the specific regulators of the specific signaling pathway based on regulatory effects.
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8
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Yan W, Tian Y, Sun P, Yang J, Li N, Sun Y, Wang S, Zhang C. Dok-3 deficient mice display different immune clustering and Tim-3 expression. Eur J Med Res 2019; 24:26. [PMID: 31351483 PMCID: PMC6660655 DOI: 10.1186/s40001-019-0384-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 07/15/2019] [Indexed: 11/23/2022] Open
Abstract
Background Dok-3 has been shown to play an important role in immune system. Tim-3 also has been recognized as an important immune regulator which involves in many diseases. The relationship of them is still unclear. Methods We detected the expression of Tim-3 on spleen immune cells from Dok-3 deficient mice and control mice by flow cytometry. Results In this article, we found that Dok-3−/− mice display almost entirely different immune clustering characteristics compared with wild type 129 mice. The CD4 T cells and CD8 T cells decreased and DC cells, macrophages, MDSCs increased when the Dok-3 gene knocked-out. The Tim-3 expression on CD4 T cells, CD8 T cells, NK cells, DC cells increased when the Dok-3 gene knocked-out. The macrophages and MDSCs just display the opposite results. Conclusions Although Dok-3−/− mice display different immune clustering and Tim-3 expression, the mechanism still needs further study. Electronic supplementary material The online version of this article (10.1186/s40001-019-0384-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenjiang Yan
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China.,Key Laboratory of Infection and Immunity of Shandong Province, Jinan, China
| | - Yijia Tian
- Grade 2015, School of Basic Medical Sciences, Clinical Medicine(5 + 3), Shandong University, Jinan, Shandong, China
| | - Peng Sun
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China.,Department of Intervention Oncology, Shandong Cancer Hospital and Institute, Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Jingjing Yang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China
| | - Na Li
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China
| | - Yuanyuan Sun
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China
| | - Shuangxi Wang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China.
| | - Cheng Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, and The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, No. 107 Wenhua Xi Road, Jinan, Shandong, China.
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9
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Loh JT, Xu S, Huo JX, Kim SSY, Wang Y, Lam KP. Dok3-protein phosphatase 1 interaction attenuates Card9 signaling and neutrophil-dependent antifungal immunity. J Clin Invest 2019; 129:2717-2729. [PMID: 31180338 DOI: 10.1172/jci126341] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Invasive fungal infection is a serious health threat with high morbidity and mortality. Current antifungal drugs only demonstrate partial success in improving prognosis. Furthermore, mechanisms regulating host defense against fungal pathogens remain elusive. Here, we report that the downstream of kinase 3 (Dok3) adaptor negatively regulates antifungal immunity in neutrophils. Our data revealed that Dok3 deficiency increased phagocytosis, proinflammatory cytokine production, and netosis in neutrophils, thereby enhancing mutant mouse survival against systemic infection with a lethal dose of the pathogenic fungus Candida albicans. Biochemically, Dok3 recruited protein phosphatase 1 (PP1) to dephosphorylate Card9, an essential player in innate antifungal defense, to dampen downstream NF-κB and JNK activation and immune responses. Thus, Dok3 suppresses Card9 signaling, and disrupting Dok3-Card9 interaction or inhibiting PP1 activity represents therapeutic opportunities to develop drugs to combat candidaemia.
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Affiliation(s)
- Jia Tong Loh
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore
| | - Shengli Xu
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jian Xin Huo
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore
| | - Susana Soo-Yeon Kim
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Department of Biochemistry and
| | - Kong-Peng Lam
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,School of Biological Sciences, College of Science, Nanyang Technological University, Singapore
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10
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Chen Y, Fachko D, Ivanov NS, Skinner CM, Skalsky RL. Epstein-Barr virus microRNAs regulate B cell receptor signal transduction and lytic reactivation. PLoS Pathog 2019; 15:e1007535. [PMID: 30615681 PMCID: PMC6336353 DOI: 10.1371/journal.ppat.1007535] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/17/2019] [Accepted: 12/17/2018] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) are post-transcriptional regulatory RNAs that can modulate cell signaling and play key roles in cell state transitions. Epstein-Barr virus (EBV) expresses >40 viral miRNAs that manipulate both viral and cellular gene expression patterns and contribute to reprogramming of the host environment during infection. Here, we identified a subset of EBV miRNAs that desensitize cells to B cell receptor (BCR) stimuli, and attenuate the downstream activation of NF-kappaB or AP1-dependent transcription. Bioinformatics and pathway analysis of Ago PAR-CLIP datasets identified multiple EBV miRNA targets related to BCR signal transduction, including GRB2, SOS1, MALT1, RAC1, and INPP5D, which we validated in reporter assays. BCR signaling is critical for B cell activation, proliferation, and differentiation, and for EBV, is linked to reactivation. In functional assays, we demonstrate that EBV miR-BHRF1-2-5p contributes to the growth of latently infected B cells through GRB2 regulation. We further determined that activities of EBV miR-BHRF1-2-5p, EBV miR-BART2-5p, and a cellular miRNA, miR-17-5p, directly regulate virus reactivation triggered by BCR engagement. Our findings provide mechanistic insight into some of the key miRNA interactions impacting the proliferation of latently infected B cells and importantly, governing the latent to lytic switch.
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Affiliation(s)
- Yan Chen
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Devin Fachko
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Nikita S. Ivanov
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Camille M. Skinner
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Rebecca L. Skalsky
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
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11
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Clark EA, Giltiay NV. CD22: A Regulator of Innate and Adaptive B Cell Responses and Autoimmunity. Front Immunol 2018; 9:2235. [PMID: 30323814 PMCID: PMC6173129 DOI: 10.3389/fimmu.2018.02235] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022] Open
Abstract
CD22 (Siglec 2) is a receptor predominantly restricted to B cells. It was initially characterized over 30 years ago and named “CD22” in 1984 at the 2nd International workshop in Boston (1). Several excellent reviews have detailed CD22 functions, CD22-regulated signaling pathways and B cell subsets regulated by CD22 or Siglec G (2–4). This review is an attempt to highlight recent and possibly forgotten findings. We also describe the role of CD22 in autoimmunity and the great potential for CD22-based immunotherapeutics for the treatment of autoimmune diseases such as systemic lupus erythematosus (SLE).
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Affiliation(s)
- Edward A Clark
- Department of Immunology, University of Washington, Seattle, WA, United States.,Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, United States
| | - Natalia V Giltiay
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, United States
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12
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Affiliation(s)
- Niklas Engels
- Institute of Cellular & Molecular Immunology; University Medical Center Göttingen; Göttingen Germany
| | - Jürgen Wienands
- Institute of Cellular & Molecular Immunology; University Medical Center Göttingen; Göttingen Germany
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13
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Vanshylla K, Bartsch C, Hitzing C, Krümpelmann L, Wienands J, Engels N. Grb2 and GRAP connect the B cell antigen receptor to Erk MAP kinase activation in human B cells. Sci Rep 2018; 8:4244. [PMID: 29523808 PMCID: PMC5844867 DOI: 10.1038/s41598-018-22544-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/19/2018] [Indexed: 11/09/2022] Open
Abstract
The B cell antigen receptor (BCR) employs enzymatically inactive adaptor proteins to facilitate activation of intracellular signaling pathways. In animal model systems, adaptor proteins of the growth factor receptor-bound 2 (Grb2) family have been shown to serve critical functions in lymphocytes. However, the roles of Grb2 and the Grb2-related adaptor protein (GRAP) in human B lymphocytes remain unclear. Using TALEN-mediated gene targeting, we show that in human B cells Grb2 and GRAP amplify signaling by the immunoglobulin tail tyrosine (ITT) motif of mIgE-containing BCRs and furthermore connect immunoreceptor tyrosine-based activation motif (ITAM) signaling to activation of the Ras-controlled Erk MAP kinase pathway. In contrast to mouse B cells, BCR-induced activation of Erk in human B cells is largely independent of phospholipase C-ɣ activity and diacylglycerol-responsive members of Ras guanine nucleotide releasing proteins. Together, our results demonstrate that Grb2 family adaptors are critical regulators of ITAM and ITT signaling in naïve and IgE-switched human B cells.
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Affiliation(s)
- Kanika Vanshylla
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Caren Bartsch
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Christoffer Hitzing
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Laura Krümpelmann
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Jürgen Wienands
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Niklas Engels
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany.
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14
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Brodie EJ, Infantino S, Low MSY, Tarlinton DM. Lyn, Lupus, and (B) Lymphocytes, a Lesson on the Critical Balance of Kinase Signaling in Immunity. Front Immunol 2018; 9:401. [PMID: 29545808 PMCID: PMC5837976 DOI: 10.3389/fimmu.2018.00401] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/13/2018] [Indexed: 01/23/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is a progressive autoimmune disease characterized by increased sensitivity to self-antigens, auto-antibody production, and systemic inflammation. B cells have been implicated in disease progression and as such represent an attractive therapeutic target. Lyn is a Src family tyrosine kinase that plays a major role in regulating signaling pathways within B cells as well as other hematopoietic cells. Its role in initiating negative signaling cascades is especially critical as exemplified by Lyn-/- mice developing an SLE-like disease with plasma cell hyperplasia, underscoring the importance of tightly regulating signaling within B cells. This review highlights recent advances in our understanding of the function of the Src family tyrosine kinase Lyn in B lymphocytes and its contribution to positive and negative signaling pathways that are dysregulated in autoimmunity.
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Affiliation(s)
- Erica J. Brodie
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Simona Infantino
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Michael S. Y. Low
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
- Immunology Division, Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC, Australia
- Department of Haematology, Monash Health, Monash Hospital, Clayton, VIC, Australia
| | - David M. Tarlinton
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
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15
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PD-1 and its ligands are important immune checkpoints in cancer. Oncotarget 2018; 8:2171-2186. [PMID: 27974689 PMCID: PMC5356790 DOI: 10.18632/oncotarget.13895] [Citation(s) in RCA: 210] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 11/21/2016] [Indexed: 12/31/2022] Open
Abstract
Checkpoint programmed death-1 (PD-1)/programmed cell death ligands (PD-Ls) have been identified as negative immunoregulatory molecules that promote immune evasion of tumor cells. The interaction of PD-1 and PD-Ls inhibits the function of T cells and tumor-infiltrating lymphocytes (TIL) while increasing the function of immunosuppressive regulatory T cells (Tregs). This condition causes the tumor cells to evade immune response. Thus, the blockade of PD-1/PD-L1 enhances anti-tumor immunity by reducing the number and/or the suppressive activity of Tregs and by restoring the activity of effector T cells. Furthermore, some monoclonal antibodies blockading PD-1/PD-Ls axis have achieved good effect and received Food and Drug Administration approval. The role of PD-1/PD-Ls in tumors has been well studied, but little is known on the mechanism by which PD-1 blocks T-cell activation. In this study, we provide a brief overview on the discovery and regulatory mechanism of PD-1 and PD-L1 dysregulation in tumors, as well as the function and signaling pathway of PD-1 and its ligands; their roles in tumor evasion and clinical treatment were also studied.
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16
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Chen J, Wang H, Xu WP, Wei SS, Li HJ, Mei YQ, Li YG, Wang YP. Besides an ITIM/SHP-1-dependent pathway, CD22 collaborates with Grb2 and plasma membrane calcium-ATPase in an ITIM/SHP-1-independent pathway of attenuation of Ca2+i signal in B cells. Oncotarget 2018; 7:56129-56146. [PMID: 27276708 PMCID: PMC5302901 DOI: 10.18632/oncotarget.9794] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/14/2016] [Indexed: 12/30/2022] Open
Abstract
CD22 is a surface immunoglobulin implicated in negative regulation of B cell receptor (BCR) signaling; particularly inhibiting intracellular Ca2+ (Ca2+i)signals. Its cytoplasmic tail contains six tyrosine residues (Y773/Y783/Y817/Y828/Y843/Y863, designated Y1~Y6 respectively), including three (Y2/5/6) lying within immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that serve to recruit the protein tyrosine phosphatase SHP-1 after BCR activation-induced phosphorylation. The mechanism of inhibiting Ca2+i by CD22 has been poorly understood. Previous study demonstrated that CD22 associated with plasma membrane calcium-ATPase (PMCA) and enhanced its activity (Chen, J. et al. Nat Immunol 2004;5:651-7). The association is dependent on BCR activation-induced cytoplasmic tyrosine phosphorylation, because CD22 with either all six tyrosines mutated to phenylalanines or cytoplasmic tail truncated loses its ability to associate with PMCA. However, which individual or a group of tyrosine residues determine the association and how CD22 and PMCA interacts, are still unclear. In this study, by using a series of CD22 tyrosine mutants, we found that ITIM Y2/5/6 accounts for 34.3~37.1% Ca2+i inhibition but is irrelevant for CD22/PMCA association. Non-ITIM Y4 and its YEND motif contribute to the remaining 69.4~71.7% Ca2+i inhibition and is the binding site for PMCA-associated Grb2. Grb2, independently of BCR cross-linking, is constitutively associated with and directly binds to PMCA in both chicken and human B cells. Knockout of Grb2 by CRISPR/Cas9 completely disrupted the CD22/PMCA association. Thus, our results demonstrate for the first time that in addition to previously-identified ITIM/SHP-1-dependent pathway, CD22 holds a major pathway of negative regulation of Ca2+i signal, which is ITIM/SHP-1-independent, but Y4/Grb2/PMCA-dependent.
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Affiliation(s)
- Jie Chen
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Hong Wang
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Wei-Ping Xu
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Si-Si Wei
- Department of Pediatrics, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Hui Joyce Li
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Yun-Qing Mei
- Department of Cardio-Thoracic Surgery, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi-Gang Li
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Yue-Peng Wang
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
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17
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Unperturbed Immune Function despite Mutation of C-Terminal Tyrosines in Syk Previously Implicated in Signaling and Activity Regulation. Mol Cell Biol 2017; 37:MCB.00216-17. [PMID: 28760774 DOI: 10.1128/mcb.00216-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/26/2017] [Indexed: 11/20/2022] Open
Abstract
The nonreceptor tyrosine kinase Syk, a central regulator of immune cell differentiation and activation, is a promising drug target for treatment of leukemia and allergic and inflammatory diseases. The clinical failure of Syk inhibitors underscores the importance of understanding the regulation of Syk function and activity. A series of previous studies emphasized the importance of three C-terminal tyrosines in Syk for kinase activity regulation, as docking sites for downstream effector molecules, and for Ca2+ mobilization. Here, we investigated the roles of these C-terminal tyrosines in the mouse. Surprisingly, expression of a triple tyrosine-to-phenylalanine human Syk mutant, SYK(Y3F), was not associated with discernible signaling defects either in reconstituted DT40 cells or in B or mast cells from mice expressing SYK(Y3F) instead of wild-type Syk. Remarkably, lymphocyte differentiation, calcium mobilization, and 2,4,6-trinitrophenyl (TNP)-specific immune responses were unperturbed in SYK(Y3F) mice. These results emphasize the capacity of immune cells to compensate for specific molecular defects, likely using redundant intermolecular interactions, and highlight the importance of in vivo analyses for understanding cellular signaling mechanisms.
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18
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Reth M, Gold MR. What goes up must come down: A tripartite Dok-3/Grb2/SHIP1 inhibitory module limits BCR signaling. Eur J Immunol 2017; 46:2507-2511. [PMID: 27813071 DOI: 10.1002/eji.201646705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 09/20/2016] [Accepted: 09/27/2016] [Indexed: 01/30/2023]
Abstract
Properly regulated immunity requires precise integration of activating and inhibitory signals. As for other lymphocytes, B cells express an antigen-specific activating receptor, the B-cell antigen receptor (BCR), and inhibitory receptors (e.g. FcγRIIb) that exercise checkpoint control on B-cell activation. Moreover, following BCR engagement, CD19 recruits proteins that amplify BCR signaling, while CD22 initiates a negative feedback loop by recruiting proteins that inhibit BCR signaling. Initial BCR signaling is mediated by protein tyrosine kinases and lipid kinases; inhibitory receptors directly antagonize the actions of these enzymes by recruiting protein tyrosine phosphatases and lipid phosphatases and positioning them close to actively signaling BCRs. Previously it was thought that inhibitory receptors such as FcγRIIb and CD22 were essential for bringing these phosphatases near the BCR. In this issue of the European Journal of Immunology, Manno et al. show that a tripartite inhibitory module consisting of the adaptor proteins Dok-3 and Grb2 and the lipid phosphatase SHIP1 binds directly to activated BCRs and limits the Ca2+ mobilization that is required for B lymphocyte activation. This reveals that the BCR can be both an activating and inhibitory receptor, one that activates signaling enzymes while initiating a negative feedback loop that prevents excessive signaling.
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Affiliation(s)
- Michael Reth
- BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Max Planck Institute for Immunobiology and Epigenetics, Freiburg, Germany
| | - Michael R Gold
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
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19
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Anguita E, Villalobo A. Src-family tyrosine kinases and the Ca 2+ signal. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:915-932. [PMID: 27818271 DOI: 10.1016/j.bbamcr.2016.10.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/25/2016] [Accepted: 10/30/2016] [Indexed: 01/08/2023]
Abstract
In this review, we shall describe the rich crosstalk between non-receptor Src-family kinases (SFKs) and the Ca2+ transient generated in activated cells by a variety of extracellular and intracellular stimuli, resulting in diverse signaling events. The exchange of information between SFKs and Ca2+ is reciprocal, as it flows in both directions. These kinases are main actors in pathways leading to the generation of the Ca2+ signal, and reciprocally, the Ca2+ signal modulates SFKs activity and functions. We will cover how SFKs participate in the generation of the cytosolic Ca2+ rise upon activation of a series of receptors and the mechanism of clearance of this Ca2+ signal. The role of SFKs modulating Ca2+-translocating channels participating in these events will be amply discussed. Finally, the role of the Ca2+ sensor protein calmodulin on the activity of c-Src, and potentially on other SFKs, will be outlined as well. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Estefanía Anguita
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain
| | - Antonio Villalobo
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/ Arturo Duperier 4, E-28029 Madrid, Spain.
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20
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Manno B, Oellerich T, Schnyder T, Corso J, Lösing M, Neumann K, Urlaub H, Batista FD, Engelke M, Wienands J. The Dok-3/Grb2 adaptor module promotes inducible association of the lipid phosphatase SHIP with the BCR in a coreceptor-independent manner. Eur J Immunol 2016; 46:2520-2530. [PMID: 27550373 DOI: 10.1002/eji.201646431] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/28/2016] [Accepted: 08/16/2016] [Indexed: 01/19/2023]
Abstract
The SH2 domain-containing inositol 5'-phosphatase (SHIP) plays a key role in preventing autoimmune phenomena by limiting antigen-mediated B cell activation. SHIP function is thought to require the dual engagement of the BCR and negative regulatory coreceptors as only the latter appear capable of recruiting SHIP from the cytosol to the plasma membrane by the virtue of phosphorylated immunoreceptor tyrosine-based inhibitory motifs. Here, we demonstrate a coreceptor-independent membrane recruitment and function of SHIP in B cells. In the absence of coreceptor ligation, SHIP translocates to sites of BCR activation through a concerted action of the protein adaptor unit Dok-3/Grb2 and phosphorylated BCR signaling components. Our data reveal auto-inhibitory SHIP activation by the activated BCR and suggest an unexpected negative-regulatory capacity of immunoreceptor tyrosine-based activation motifs in Igα and Igβ.
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Affiliation(s)
- Birgit Manno
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany
| | - Thomas Oellerich
- Department of Hematology and Oncology, Johann Wolfgang Goethe University of Frankfurt, Frankfurt, Germany
| | - Tim Schnyder
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute London, UK
| | - Jasmin Corso
- Bioanalytical Mass Spectrometry, Max Planck Institute of Biophysical Chemistry, Göttingen
| | - Marion Lösing
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.,Vivo Science GmbH, Gronau, Germany
| | - Konstantin Neumann
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.,Institute of Clinical Chemistry, Hannover Medical School, Hannover, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute of Biophysical Chemistry, Göttingen.,Bioanalytics Department of Clincal Chemistry, University Medical Center Goettingen, Göttingen, Germany
| | - Facundo D Batista
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute London, UK
| | - Michael Engelke
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany
| | - Jürgen Wienands
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.
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21
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Justa-Schuch D, Silva-Garcia M, Pilla E, Engelke M, Kilisch M, Lenz C, Möller U, Nakamura F, Urlaub H, Geiss-Friedlander R. DPP9 is a novel component of the N-end rule pathway targeting the tyrosine kinase Syk. eLife 2016; 5. [PMID: 27614019 PMCID: PMC5039030 DOI: 10.7554/elife.16370] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/07/2016] [Indexed: 12/12/2022] Open
Abstract
The aminopeptidase DPP9 removes dipeptides from N-termini of substrates having a proline or alanine in second position. Although linked to several pathways including cell survival and metabolism, the molecular mechanisms underlying these outcomes are poorly understood. We identified a novel interaction of DPP9 with Filamin A, which recruits DPP9 to Syk, a central kinase in B-cell signalling. Syk signalling can be terminated by degradation, requiring the ubiquitin E3 ligase Cbl. We show that DPP9 cleaves Syk to produce a neo N-terminus with serine in position 1. Pulse-chases combined with mutagenesis studies reveal that Ser1 strongly influences Syk stability. Furthermore, DPP9 silencing reduces Cbl interaction with Syk, suggesting that DPP9 processing is a prerequisite for Syk ubiquitination. Consistently, DPP9 inhibition stabilizes Syk, thereby modulating Syk signalling. Taken together, we demonstrate DPP9 as a negative regulator of Syk and conclude that DPP9 is a novel integral aminopeptidase of the N-end rule pathway.
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Affiliation(s)
- Daniela Justa-Schuch
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Maria Silva-Garcia
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Esther Pilla
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Michael Engelke
- Institute of Cellular and Molecular Immunology, University Medical Center Goettingen, Goettingen, Germany
| | - Markus Kilisch
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Christof Lenz
- Department of Bioanalytics, Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ulrike Möller
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Fumihiko Nakamura
- Hematology Division, Department of Medicine, Harvard Medical School, Boston, United States.,Brigham and Women's Hospital, Boston, United States
| | - Henning Urlaub
- Department of Bioanalytics, Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ruth Geiss-Friedlander
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
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22
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TRAF6-mediated degradation of DOK3 is required for production of IL-6 and TNFα in TLR9 signaling. Mol Immunol 2015; 68:699-705. [DOI: 10.1016/j.molimm.2015.10.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/26/2015] [Accepted: 10/27/2015] [Indexed: 01/19/2023]
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23
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Freedman TS, Tan YX, Skrzypczynska KM, Manz BN, Sjaastad FV, Goodridge HS, Lowell CA, Weiss A. LynA regulates an inflammation-sensitive signaling checkpoint in macrophages. eLife 2015; 4. [PMID: 26517880 PMCID: PMC4626889 DOI: 10.7554/elife.09183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/19/2015] [Indexed: 12/11/2022] Open
Abstract
Clustering of receptors associated with immunoreceptor tyrosine-based activation motifs (ITAMs) initiates the macrophage antimicrobial response. ITAM receptors engage Src-family tyrosine kinases (SFKs) to initiate phagocytosis and macrophage activation. Macrophages also encounter nonpathogenic molecules that cluster receptors weakly and must tune their sensitivity to avoid inappropriate responses. To investigate this response threshold, we compared signaling in the presence and absence of receptor clustering using a small-molecule inhibitor of Csk, which increased SFK activation and produced robust membrane-proximal signaling. Surprisingly, receptor-independent SFK activation led to a downstream signaling blockade associated with rapid degradation of the SFK LynA. Inflammatory priming of macrophages upregulated LynA and promoted receptor-independent signaling. In contrast, clustering the hemi-ITAM receptor Dectin-1 induced signaling that did not require LynA or inflammatory priming. Together, the basal-state signaling checkpoint regulated by LynA expression and degradation and the signaling reorganization initiated by receptor clustering allow cells to discriminate optimally between pathogens and nonpathogens.
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Affiliation(s)
- Tanya S Freedman
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States.,Department of Pharmacology, Center for Immunology, University of Minnesota, Minneapolis, United States
| | - Ying X Tan
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Katarzyna M Skrzypczynska
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Boryana N Manz
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Frances V Sjaastad
- Department of Pharmacology, Center for Immunology, University of Minnesota, Minneapolis, United States
| | - Helen S Goodridge
- Regenerative Medicine Institute and Research Division of Immunology, Cedars-Sinai Medical Center, Los Angeles, United States
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, United States
| | - Arthur Weiss
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California, San Francisco, Chevy Chase, United States
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24
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Chen X, Li G, Wan Z, Liu C, Zeng Y, Liu W. How B cells remember? A sophisticated cytoplasmic tail of mIgG is pivotal for the enhanced transmembrane signaling of IgG-switched memory B cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 118:89-94. [PMID: 26004919 DOI: 10.1016/j.pbiomolbio.2015.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 11/26/2022]
Abstract
Antibody memory is critical for protection against many human infectious diseases and is the basis for nearly all current human vaccines. Isotype switched immunoglobulin (Ig) G-expressing memory B cells are considered as one of the fundaments for the rapid, high affinity and high-titered memory antibody response. The detailed molecular mechanism of the enhanced activation of IgG-switched memory B cells upon BCR engagement with antigens has been an elusive question in immunology. In this review, we tried to discuss all the exciting new advances revealing the molecular mechanisms of the transmembrane signaling through mIgG cytoplasmic tail in IgG-switched memory B cells.
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Affiliation(s)
- Xiangjun Chen
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center for Infectious Diseases, HangZhou, China
| | - Gen Li
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhengpeng Wan
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ce Liu
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yingyue Zeng
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wanli Liu
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center for Infectious Diseases, HangZhou, China.
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25
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Hobeika E, Nielsen PJ, Medgyesi D. Signaling mechanisms regulating B-lymphocyte activation and tolerance. J Mol Med (Berl) 2015; 93:143-58. [PMID: 25627575 DOI: 10.1007/s00109-015-1252-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/15/2014] [Accepted: 12/25/2014] [Indexed: 01/01/2023]
Abstract
It is becoming more and more accepted that, in addition to producing autoantibodies, B lymphocytes have other important functions that influence the development of autoimmunity. For example, autoreactive B cells are able to produce inflammatory cytokines and activate pathogenic T cells. B lymphocytes can react to extracellular signals with a range of responses from anergy to autoreactivity. The final outcome is determined by the relative contribution of signaling events mediated by activating and inhibitory pathways. Besides the B cell antigen receptor (BCR), several costimulatory receptors expressed on B cells can also induce B cell proliferation and survival, or regulate antibody production. These include CD19, CD40, the B cell activating factor receptor, and Toll-like receptors. Hyperactivity of these receptors clearly contributes to breaking B-cell tolerance in several autoimmune diseases. Inhibitors of these activating signals (including protein tyrosine phosphatases, deubiquitinating enzymes and several adaptor proteins) are crucial to control B-cell activation and maintain B-cell tolerance. In this review, we summarize the inhibitory signaling mechanisms that counteract B-cell activation triggered by the BCR and the coreceptors.
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Affiliation(s)
- Elias Hobeika
- BIOSS Centre of Biological Signalling Studies, University of Freiburg and Department for Molecular Immunology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
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26
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Baba Y, Kurosaki T. Role of Calcium Signaling in B Cell Activation and Biology. Curr Top Microbiol Immunol 2015; 393:143-174. [PMID: 26369772 DOI: 10.1007/82_2015_477] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase in intracellular levels of calcium ions (Ca2+) is one of the key triggering signals for the development of B cell response to the antigen. The diverse Ca2+ signals finely controlled by multiple factors participate in the regulation of gene expression, B cell development, and effector functions. B cell receptor (BCR)-initiated Ca2+ mobilization is sourced from two pathways: one is the release of Ca2+ from the intracellular stores, endoplasmic reticulum (ER), and other is the prolonged influx of extracellular Ca2+ induced by depleting the stores via store-operated calcium entry (SOCE) and calcium release-activated calcium (CRAC) channels. The identification of stromal interaction molecule 1(STIM1), the ER Ca2+ sensor, and Orai1, a key subunit of the CRAC channel pore, has now provided the tools to understand the mode of Ca2+ influx regulation and physiological relevance. Herein, we discuss our current understanding of the molecular mechanisms underlying BCR-triggered Ca2+ signaling as well as its contribution to the B cell biological processes and diseases.
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Affiliation(s)
- Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan. .,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan.
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan.,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan
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27
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Engels N, König LM, Schulze W, Radtke D, Vanshylla K, Lutz J, Winkler TH, Nitschke L, Wienands J. The immunoglobulin tail tyrosine motif upgrades memory-type BCRs by incorporating a Grb2-Btk signalling module. Nat Commun 2014; 5:5456. [PMID: 25413232 PMCID: PMC4263166 DOI: 10.1038/ncomms6456] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 10/02/2014] [Indexed: 11/25/2022] Open
Abstract
The vigorous response of IgG-switched memory B cells to recurring pathogens involves enhanced signalling from their B-cell antigen receptors (BCRs). However, the molecular signal amplification mechanisms of memory-type BCRs remained unclear. Here, we identify the immunoglobulin tail tyrosine (ITT) motif in the cytoplasmic segments of membrane-bound IgGs (mIgGs) as the principle signal amplification device of memory-type BCRs in higher vertebrates and decipher its signalling microanatomy. We show that different families of protein tyrosine kinases act upstream and downstream of the ITT. Spleen tyrosine kinase (Syk) activity is required for ITT phosphorylation followed by recruitment of the adaptor protein Grb2 into the mIgG-BCR signalosome. Grb2 in turn recruits Bruton's tyrosine kinase (Btk) to amplify BCR-induced Ca(2+) mobilization. This molecular interplay of kinases and adaptors increases the antigen sensitivity of memory-type BCRs, which provides a cell-intrinsic trigger mechanism for the rapid reactivation of IgG-switched memory B cells on antigen recall.
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Affiliation(s)
- Niklas Engels
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
| | - Lars M. König
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
| | - Wiebke Schulze
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
| | - Daniel Radtke
- Chair of Genetics, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Kanika Vanshylla
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
| | - Johannes Lutz
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
| | - Thomas H. Winkler
- Hematopoiesis Unit, Department of Biology, Nikolaus-Fiebiger-Center for Molecular Medicine, Friedrich-Alexander-University Erlangen-Nürnberg, Glückstrasse 6, 91054 Erlangen, Germany
| | - Lars Nitschke
- Chair of Genetics, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Jürgen Wienands
- Institute of Cellular and Molecular Immunology, Georg-August-University of Göttingen, Medical Faculty, Humboldtallee 34, 37073 Göttingen, Germany
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28
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Engelke M, Pirkuliyeva S, Kühn J, Wong L, Boyken J, Herrmann N, Becker S, Griesinger C, Wienands J. Macromolecular assembly of the adaptor SLP-65 at intracellular vesicles in resting B cells. Sci Signal 2014; 7:ra79. [PMID: 25140054 DOI: 10.1126/scitranslmed.2005104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The traditional view of how intracellular effector proteins are recruited to the B cell antigen receptor (BCR) complex at the plasma membrane is based on the occurrence of direct protein-protein interactions, as exemplified by the recruitment of the tyrosine kinase Syk (spleen tyrosine kinase) to phosphorylated motifs in BCR signaling subunits. By contrast, the subcellular targeting of the cytosolic adaptor protein SLP-65 (Src homology 2 domain-containing leukocyte adaptor protein of 65 kD), which serves as a proximal Syk substrate, is unclear. We showed that SLP-65 activation required its association at vesicular compartments in resting B cells. A module of ~50 amino acid residues located at the amino terminus of SLP-65 anchored SLP-65 to the vesicles. Nuclear magnetic resonance spectroscopy showed that the SLP-65 amino terminus was structurally disordered in solution but could bind in a structured manner to noncharged lipid components of cellular membranes. Our finding that preformed vesicular signaling scaffolds are required for B cell activation indicates that vesicles may deliver preassembled signaling cargo to sites of BCR activation.
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Affiliation(s)
- Michael Engelke
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany
| | - Sona Pirkuliyeva
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany
| | - Julius Kühn
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany
| | - Leo Wong
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Janina Boyken
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Nadine Herrmann
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jürgen Wienands
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany.
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Adaptor protein DOK3 promotes plasma cell differentiation by regulating the expression of programmed cell death 1 ligands. Proc Natl Acad Sci U S A 2014; 111:11431-6. [PMID: 25053811 DOI: 10.1073/pnas.1400539111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The adaptor Downstream-of-Kinase (DOK) 3 functions as a negative regulator and attenuates B-cell receptor-mediated calcium signaling. Although DOK3 is dispensable for early B-cell development, its role in plasma cell (PC) differentiation is unknown. Here, we show that Dok3(-/-) mice have increased populations of T follicular-helper (Tfh) and germinal center (GC) B cells upon immunization with a T-cell-dependent antigen. However, interestingly, they generate significantly fewer PCs. Bone marrow reconstitution experiments show that the PC defect is B-cell intrinsic and due to the inability of Dok3(-/-) B cells to sustain programmed cell death 1 (PD-1) ligand 1 (PDL1) and up-regulate PD-1 ligand 2 (PDL2) expressions that are critical for PC differentiation. Overexpression of PDL2 rectifies the PC differentiation defect in Dok3(-/-) B cells. We further demonstrate that calcium signaling suppresses the transcription of PD-1 ligands. Abrogation of calcium signaling in B cells by deleting BTK or PLCγ2 or inhibiting calcineurin with cyclosporine A leads to increased expression of PD-1 ligands. Thus, our study reveals DOK3 as a nonredundant regulator of PC differentiation by up-regulating PD-1 ligand expression through the attenuation of calcium signaling.
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30
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Kim SSY, Lee KG, Chin CS, Ng SK, Pereira NA, Xu S, Lam KP. DOK3 is required for IFN-β production by enabling TRAF3/TBK1 complex formation and IRF3 activation. THE JOURNAL OF IMMUNOLOGY 2014; 193:840-8. [PMID: 24929003 DOI: 10.4049/jimmunol.1301601] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The downstream of kinase (DOK) family of adaptors is generally involved in the negative regulation of signaling pathways. DOK1, 2, and 3 were shown to attenuate TLR4 signaling by inhibiting Ras-ERK activation. In this study, we elucidated a novel role for DOK3 in IFN-β production. Macrophages lacking DOK3 were impaired in IFN-β synthesis upon influenza virus infection or polyinosinic-polyribocytidylic acid stimulation. In the absence of DOK3, the transcription factor IFN regulatory factor 3 was not phosphorylated and could not translocate to the nucleus to activate ifn-β gene expression. Interestingly, polyinosinic-polyribocytidylic acid-induced formation of the upstream TNFR-associated factor (TRAF) 3/TANK-binding kinase (TBK) 1 complex was compromised in dok3(-/-) macrophages. DOK3 was shown to bind TBK1 and was required for its activation. Furthermore, we demonstrated that overexpression of DOK3 and TBK1 could significantly enhance ifn-β promoter activity. DOK3 was also shown to bind TRAF3, and the binding of TRAF3 and TBK1 to DOK3 required the tyrosine-rich C-terminal domain of DOK3. We further revealed that DOK3 was phosphorylated by Bruton's tyrosine kinase. Hence, DOK3 plays a critical and positive role in TLR3 signaling by enabling TRAF3/TBK1 complex formation and facilitating TBK1 and IFN regulatory factor 3 activation and the induction of IFN-β production.
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Affiliation(s)
- Susana Soo-Yeon Kim
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228; Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Koon-Guan Lee
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Ching-Siang Chin
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Say-Kong Ng
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Natasha Ann Pereira
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Shengli Xu
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and
| | - Kong-Peng Lam
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228; Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668; and Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228
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31
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Xu Y, Xu L, Zhao M, Xu C, Fan Y, Pierce SK, Liu W. No receptor stands alone: IgG B-cell receptor intrinsic and extrinsic mechanisms contribute to antibody memory. Cell Res 2014; 24:651-64. [PMID: 24839903 PMCID: PMC4042179 DOI: 10.1038/cr.2014.65] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Acquired immunological memory is a striking phenomenon. A lethal epidemic sweeps through a naïve population, many die but those who survive are never "attacked twice - never at least fatally", as the historian Thucydides observed in 430 BCE. Antibody memory is critical for protection against many human infectious diseases and is the basis for nearly all current human vaccines. Antibody memory is encoded, in part, in isotype-switched immunoglobulin (Ig)G-expressing memory B cells that are generated in the primary response to antigen and give rise to rapid, high-affinity and high-titered antibody responses upon challenge with the same antigen. How IgG-B-cell receptors (BCRs) and antigen-induced IgG-BCR signaling contribute to memory antibody responses are not fully understood. In this review, we summarize exciting new advances that are revealing the cellular and molecular mechanisms at play in antibody memory and discuss how studies using different experimental approaches will help elucidate the complex phenomenon of B-cell memory.
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Affiliation(s)
- Yinsheng Xu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing 100084, China
| | - Liling Xu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng Zhao
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - ChenGuang Xu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yilin Fan
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852, USA
| | - Wanli Liu
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing 100084, China
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32
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Hughan SC, Spring CM, Schoenwaelder SM, Sturgeon S, Alwis I, Yuan Y, McFadyen JD, Westein E, Goddard D, Ono A, Yamanashi Y, Nesbitt WS, Jackson SP. Dok-2 adaptor protein regulates the shear-dependent adhesive function of platelet integrin αIIbβ3 in mice. J Biol Chem 2014; 289:5051-60. [PMID: 24385425 DOI: 10.1074/jbc.m113.520148] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Dok proteins are a family of adaptor molecules that have a well defined role in regulating cellular migration, immune responses, and tumor progression. Previous studies have demonstrated that Doks-1 to 3 are expressed in platelets and that Dok-2 is tyrosine-phosphorylated downstream of integrin αIIbβ3, raising the possibility that it participates in integrin αIIbβ3 outside-in signaling. We demonstrate that Dok-2 in platelets is primarily phosphorylated by Lyn kinase. Moreover, deficiency of Dok-2 leads to dysregulated integrin αIIbβ3-dependent cytosolic calcium flux and phosphatidylinositol(3,4)P2 accumulation. Although agonist-induced integrin αIIbβ3 affinity regulation was unaltered in Dok-2(-/-) platelets, Dok-2 deficiency was associated with a shear-dependent increase in integrin αIIbβ3 adhesive function, resulting in enhanced platelet-fibrinogen and platelet-platelet adhesive interactions under flow. This increase in adhesion was restricted to discoid platelets and involved the shear-dependent regulation of membrane tethers. Dok-2 deficiency was associated with an increased rate of platelet aggregate formation on thrombogenic surfaces, leading to accelerated thrombus growth in vivo. Overall, this study defines an important role for Dok-2 in regulating biomechanical adhesive function of discoid platelets. Moreover, they define a previously unrecognized prothrombotic mechanism that is not detected by conventional platelet function assays.
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Affiliation(s)
- Sascha C Hughan
- From the Australian Centre for Blood Diseases, Faculty of Medicine, Nursing, and Health Sciences, Monash University, Alfred Medical Research and Education Precinct, Commercial Road, Melbourne, Victoria 3004
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33
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Castello A, Gaya M, Tucholski J, Oellerich T, Lu KH, Tafuri A, Pawson T, Wienands J, Engelke M, Batista FD. Nck-mediated recruitment of BCAP to the BCR regulates the PI(3)K-Akt pathway in B cells. Nat Immunol 2013; 14:966-75. [PMID: 23913047 DOI: 10.1038/ni.2685] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 07/10/2013] [Indexed: 12/13/2022]
Abstract
The adaptor Nck links receptor signaling to cytoskeleton regulation. Here we found that Nck also controlled the phosphatidylinositol-3-OH kinase (PI(3)K)-kinase Akt pathway by recruiting the adaptor BCAP after activation of B cells. Nck bound directly to the B cell antigen receptor (BCR) via the non-immunoreceptor tyrosine-based activation motif (ITAM) phosphorylated tyrosine residue at position 204 in the tail of the immunoglobulin-α component. Genetic ablation of Nck resulted in defective BCR signaling, which led to hampered survival and proliferation of B cells in vivo. Indeed, antibody responses in Nck-deficient mice were also considerably impaired. Thus, we demonstrate a previously unknown adaptor function for Nck in recruiting BCAP to sites of BCR signaling and thereby modulating the PI(3)K-Akt pathway in B cells.
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Affiliation(s)
- Angelo Castello
- Lymphocyte Interaction Laboratory, London Research Institute-Cancer Research UK, London, UK
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34
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Peng Q, Long CL, Malhotra S, Humphrey MB. A physical interaction between the adaptor proteins DOK3 and DAP12 is required to inhibit lipopolysaccharide signaling in macrophages. Sci Signal 2013; 6:ra72. [PMID: 23962980 DOI: 10.1126/scisignal.2003801] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNAX-activating protein of 12 kD (DAP12) is an immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptor protein found in myeloid cells and natural killer cells, and it couples to various receptors that mediate either cellular activation or inhibition. DAP12 inhibits Toll-like receptor (TLR) signaling, such as that of TLR4 in response to its ligand lipopolysaccharide (LPS), as well as cytokine responses by coupling to TREM2 (triggering receptor expressed on myeloid cells 2) at the plasma membrane. Understanding the mechanisms that inhibit inflammatory responses in macrophages is important for the development of therapies to treat inflammatory diseases. We show that inhibition of LPS responses by DAP12 is mediated by the adaptor protein DOK3 (downstream of kinase 3). DOK3 physically associated with the ITAM of DAP12 through its phosphotyrosine-binding domain. In response to LPS, DOK3 was phosphorylated in a DAP12- and Src-dependent manner, which led to translocation of phosphorylated DOK3 to the plasma membrane. DOK3-deficient cells exhibited increased production of proinflammatory cytokines and activation of extracellular signal-regulated kinase (ERK). Compared to wild-type mice, DOK3-deficient mice had increased susceptibility to challenge with a sublethal dose of LPS and produced increased serum concentrations of the inflammatory cytokine tumor necrosis factor-α (TNF-α). Together, these data suggest the mechanism by which DAP12 and TREM2 inhibit LPS signaling in macrophages to prevent inflammation.
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Affiliation(s)
- Qisheng Peng
- Key Laboratory for Zoonosis Research, Ministry of Education, Jilin University, Changchun 130062, China
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35
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Kundu K, Costa F, Huber M, Reth M, Backofen R. Semi-supervised prediction of SH2-peptide interactions from imbalanced high-throughput data. PLoS One 2013; 8:e62732. [PMID: 23690949 PMCID: PMC3656881 DOI: 10.1371/journal.pone.0062732] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 03/22/2013] [Indexed: 01/08/2023] Open
Abstract
Src homology 2 (SH2) domains are the largest family of the peptide-recognition modules (PRMs) that bind to phosphotyrosine containing peptides. Knowledge about binding partners of SH2-domains is key for a deeper understanding of different cellular processes. Given the high binding specificity of SH2, in-silico ligand peptide prediction is of great interest. Currently however, only a few approaches have been published for the prediction of SH2-peptide interactions. Their main shortcomings range from limited coverage, to restrictive modeling assumptions (they are mainly based on position specific scoring matrices and do not take into consideration complex amino acids inter-dependencies) and high computational complexity. We propose a simple yet effective machine learning approach for a large set of known human SH2 domains. We used comprehensive data from micro-array and peptide-array experiments on 51 human SH2 domains. In order to deal with the high data imbalance problem and the high signal-to-noise ration, we casted the problem in a semi-supervised setting. We report competitive predictive performance w.r.t. state-of-the-art. Specifically we obtain 0.83 AUC ROC and 0.93 AUC PR in comparison to 0.71 AUC ROC and 0.87 AUC PR previously achieved by the position specific scoring matrices (PSSMs) based SMALI approach. Our work provides three main contributions. First, we showed that better models can be obtained when the information on the non-interacting peptides (negative examples) is also used. Second, we improve performance when considering high order correlations between the ligand positions employing regularization techniques to effectively avoid overfitting issues. Third, we developed an approach to tackle the data imbalance problem using a semi-supervised strategy. Finally, we performed a genome-wide prediction of human SH2-peptide binding, uncovering several findings of biological relevance. We make our models and genome-wide predictions, for all the 51 SH2-domains, freely available to the scientific community under the following URLs: http://www.bioinf.uni-freiburg.de/Software/SH2PepInt/SH2PepInt.tar.gz and http://www.bioinf.uni-freiburg.de/Software/SH2PepInt/Genome-wide-predictions.tar.gz, respectively.
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Affiliation(s)
- Kousik Kundu
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany
| | - Fabrizio Costa
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, University Clinic, RWTH Aachen University, Aachen, Germany
| | - Michael Reth
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany
- Department of Molecular Immunology, Max Planck Institute of Immunology, Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany
- Centre for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany
- Center for non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark
- * E-mail:
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36
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Lösing M, Goldbeck I, Manno B, Oellerich T, Schnyder T, Bohnenberger H, Stork B, Urlaub H, Batista FD, Wienands J, Engelke M. The Dok-3/Grb2 protein signal module attenuates Lyn kinase-dependent activation of Syk kinase in B cell antigen receptor microclusters. J Biol Chem 2013; 288:2303-13. [PMID: 23223229 PMCID: PMC3554902 DOI: 10.1074/jbc.m112.406546] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/20/2012] [Indexed: 02/02/2023] Open
Abstract
Recruitment of the growth factor receptor-bound protein 2 (Grb2) by the plasma membrane-associated adapter protein downstream of kinase 3 (Dok-3) attenuates signals transduced by the B cell antigen receptor (BCR). Here we describe molecular details of Dok-3/Grb2 signal integration and function, showing that the Lyn-dependent activation of the BCR transducer kinase Syk is attenuated by Dok-3/Grb2 in a site-specific manner. This process is associated with the SH3 domain-dependent translocation of Dok-3/Grb2 complexes into BCR microsignalosomes and augmented phosphorylation of the inhibitory Lyn target SH2 domain-containing inositol 5' phosphatase. Hence, our findings imply that Dok-3/Grb2 modulates the balance between activatory and inhibitory Lyn functions with the aim to adjust BCR signaling efficiency.
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Affiliation(s)
- Marion Lösing
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Humboldtallee 34, 37073 Göttingen, Germany
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37
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Junek S, Engelke M, Schild D, Wienands J. Spatiotemporal resolution of Ca2+signaling events by real time imaging of single B cells. FEBS Lett 2012; 586:1452-8. [DOI: 10.1016/j.febslet.2012.03.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/13/2012] [Accepted: 03/27/2012] [Indexed: 10/28/2022]
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38
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Schnyder T, Castello A, Feest C, Harwood NE, Oellerich T, Urlaub H, Engelke M, Wienands J, Bruckbauer A, Batista FD. B cell receptor-mediated antigen gathering requires ubiquitin ligase Cbl and adaptors Grb2 and Dok-3 to recruit dynein to the signaling microcluster. Immunity 2011; 34:905-18. [PMID: 21703542 DOI: 10.1016/j.immuni.2011.06.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 02/11/2011] [Accepted: 03/23/2011] [Indexed: 12/11/2022]
Abstract
The B cell receptor (BCR) mediates B cell antigen gathering and acquisition for presentation to T cells. Although the amount of antigen presentation to T cells determines the extent of B cell activation, the molecular mechanisms underlying antigen gathering remain unexplored. Here, through a combination of high-resolution imaging, genetics and quantitative mass spectrometry, we demonstrate that adaptors Grb2 and Dok-3, and ubiquitin ligase Cbl in signaling BCR microclusters mediate association with the microtubule motor dynein. Furthermore, we visualize the localization and movement of these microclusters on the underlying microtubule network. Importantly, disruption of this network or diminished dynein recruitment in Grb2-, Dok-3-, or Cbl-deficient B cells, does not influence microcluster formation or actin-dependent spreading, but abrogates directed movement of microclusters and antigen accumulation. Thus we identify a surprising but pivotal role for dynein and the microtubule network alongside Grb2, Dok-3, and Cbl in antigen gathering during B cell activation.
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Affiliation(s)
- Tim Schnyder
- Lymphocyte Interaction Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
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39
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The B-cell antigen receptor signals through a preformed transducer module of SLP65 and CIN85. EMBO J 2011; 30:3620-34. [PMID: 21822214 PMCID: PMC3181483 DOI: 10.1038/emboj.2011.251] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 07/05/2011] [Indexed: 12/27/2022] Open
Abstract
Spleen tyrosine kinase Syk and its substrate SLP65 (also called BLNK) are proximal signal transducer elements of the B-cell antigen receptor (BCR). Yet, our understanding of signal initiation and processing is limited owing to the incomplete list of SLP65 interaction partners and our ignorance of their association kinetics. We have now determined and quantified the in vivo interactomes of SLP65 in resting and stimulated B cells by mass spectrometry. SLP65 orchestrated a complex signal network of about 30 proteins that was predominantly based on dynamic interactions. However, a stimulation-independent and constant association of SLP65 with the Cbl-interacting protein of 85 kDa (CIN85) was requisite for SLP65 phosphorylation and its inducible plasma membrane translocation. In the absence of a steady SLP65/CIN85 complex, BCR-induced Ca(2+) and NF-κB responses were abrogated. Finally, live cell imaging and co-immunoprecipitation experiments further confirmed that both SLP65 and CIN85 are key components of the BCR-associated primary transducer module required for the onset and progression phases of BCR signal transduction.
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40
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Bohnenberger H, Oellerich T, Engelke M, Hsiao HH, Urlaub H, Wienands J. Complex phosphorylation dynamics control the composition of the Syk interactome in B cells. Eur J Immunol 2011; 41:1550-62. [PMID: 21469132 DOI: 10.1002/eji.201041326] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 03/14/2011] [Accepted: 03/25/2011] [Indexed: 11/08/2022]
Abstract
Spleen tyrosine kinase Syk provides critical transducer functions for a number of immune cell receptors and has been implicated in the generation of several forms of leukemias. Catalytic activity and the ability of Syk to interact with other signaling elements depend on the phosphorylation status of Syk. We have now identified and quantified the full spectrum of phosphoacceptor sites in human Syk as well as the interactome of Syk in resting and activated B cells by high-resolution mass spectrometry. While the majority of inducible phosphorylations occurred on tyrosine residues, one of the most frequently detected phosphosites encompassed serine 297 located within the linker insert distinguishing the long and short isoforms of Syk. Full-length Syk can associate with more than 25 distinct ligands including the 14-3-3γ adaptor protein, which binds directly to phosphoserine 297. The latter complex attenuates inducible plasma membrane recruitment of Syk, thereby limiting antigen receptor-proximal signaling pathways. Collectively, the established ligand library provides a basis to understand the complexity of the Syk signaling network.
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Affiliation(s)
- Hanibal Bohnenberger
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Humboldtallee, Göttingen, Germany
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41
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Oncogenic tyrosine kinases target Dok-1 for ubiquitin-mediated proteasomal degradation to promote cell transformation. Mol Cell Biol 2011; 31:2552-65. [PMID: 21536658 DOI: 10.1128/mcb.05045-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cellular transformation induced by oncogenic tyrosine kinases is a multistep process involving activation of growth-promoting signaling pathways and inactivation of suppressor molecules. Dok-1 is an adaptor protein that acts as a negative regulator of tyrosine kinase-initiated signaling and opposes oncogenic tyrosine kinase-mediated cell transformation. Findings that its loss facilitates transformation induced by oncogenic tyrosine kinases suggest that Dok-1 inactivation could constitute an intermediate step in oncogenesis driven by these oncoproteins. However, whether Dok-1 is subject to regulation by oncogenic tyrosine kinases remained unknown. In this study, we show that oncogenic tyrosine kinases, including p210(bcr-abl) and oncogenic forms of Src, downregulate Dok-1 by targeting it for degradation through the ubiquitin-proteasome pathway. This process is dependent on the tyrosine kinase activity of the oncoproteins and is mediated primarily by lysine-dependent polyubiquitination of Dok-1. Importantly, restoration of Dok-1 levels strongly suppresses transformation of cells expressing oncogenic tyrosine kinases, and this suppression is more pronounced in the context of a Dok-1 mutant that is largely refractory to oncogenic tyrosine kinase-induced degradation. Our findings suggest that proteasome-mediated downregulation of Dok-1 is a key mechanism by which oncogenic tyrosine kinases overcome the inhibitory effect of Dok-1 on cellular transformation and tumor progression.
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42
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Neumann K, Oellerich T, Heine I, Urlaub H, Engelke M. Fc gamma receptor IIb modulates the molecular Grb2 interaction network in activated B cells. Cell Signal 2011; 23:893-900. [DOI: 10.1016/j.cellsig.2011.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/14/2011] [Indexed: 12/13/2022]
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43
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Grb2 regulates B-cell maturation, B-cell memory responses and inhibits B-cell Ca2+ signalling. EMBO J 2011; 30:1621-33. [PMID: 21427701 DOI: 10.1038/emboj.2011.74] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 02/23/2011] [Indexed: 12/18/2022] Open
Abstract
Grb2 is a ubiquitously expressed adaptor protein, which activates Ras and MAP kinases in growth factor receptor signalling, while in B-cell receptor (BCR) signalling this role is controversial. In B cell lines it was shown that Grb2 can inhibit BCR-induced Ca(2+) signalling. Nonetheless, the physiological role of Grb2 in primary B cells is still unknown. We generated a B-cell-specific Grb2-deficient mouse line, which had a severe reduction of mature follicular B cells in the periphery due to a differentiation block and decreased B-cell survival. Moreover, we found several changes in important signalling pathways: enhanced BCR-induced Ca(2+) signalling, alterations in mitogen-activated protein kinase activation patterns and strongly impaired Akt activation, the latter pointing towards a defect in PI3K signalling. Interestingly, B-cell-specific Grb2-deficient mice showed impaired IgG and B-cell memory responses, and impaired germinal centre formation. Thus, Grb2-dependent signalling pathways are crucial for lymphocyte differentiation processes, as well as for control of secondary humoral immune responses.
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Abstract
Docking proteins comprise a distinct category of intracellular, noncatalytic signalling protein, that function downstream of a variety of receptor and receptor-associated tyrosine kinases and regulate diverse physiological and pathological processes. The growth factor receptor bound 2-associated binder/Daughter of Sevenless, insulin receptor substrate, fibroblast growth factor receptor substrate 2 and downstream of tyrosine kinases protein families fall into this category. This minireview focuses on the structure, function and regulation of these proteins.
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Affiliation(s)
- Tilman Brummer
- Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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Abstract
Histiocytic sarcoma (HS), a rare hematological malignancy, is an aggressive neoplasm that responds poorly to therapy. The molecular etiology and pathology of this disease remain unclear, hampering the development of an effective therapy, and there remains a need for more, and more realistic, animal models. HS cells typically show a histiocytic (ie, tissue macrophage-like) morphology and express histiocyte/macrophage markers in the absence of lymphocyte markers. In this study, we report that Dok-1(-/-)Dok-2(-/-)Dok-3(-/-) mice develop HS, but do not exhibit elevated incidence of other types of tumors. These mutant mice showed earlier mortality than wild-type (WT) or the other mutant mice, and this mortality was associated with HS. In total, 17 of 21 tumor-bearing Dok-1(-/-)Dok-2(-/-)Dok-3(-/-) mice necropsied at 25-66 weeks of age showed multiple organ spread, with osteolytic lesions and orthotopic invasion from the bone marrow to skeletal muscle. Tumors from the mice were transplantable. In addition, all Dok-1(-/-)Dok-2(-/-)Dok-3(-/-) mice, but only a small proportion of Dok-3(-/-) mice and no Dok-1(-/-)Dok-2(-/-) mice, exhibited abnormal accumulation of macrophages in the lung on necropsy at 8-12 weeks of age. Macrophages derived from Dok-1(-/-)Dok-2(-/-)Dok-3(-/-) mice displayed an exaggerated proliferative response to macrophage colony-stimulating factor (M-CSF) or granulocyte- macrophage colony-stimulating factor (GM-CSF) compared with WT and mutant controls. Together, these findings indicate that Dok-1, Dok-2, and Dok-3 cooperatively suppress aggressive HS, and commend Dok-1(-/-)Dok-2(-/-)Dok-3(-/-) mice as a useful model for the study of this neoplasia.
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Mashima R, Hishida Y, Tezuka T, Yamanashi Y. The roles of Dok family adapters in immunoreceptor signaling. Immunol Rev 2010; 232:273-85. [PMID: 19909370 DOI: 10.1111/j.1600-065x.2009.00844.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mammalian Dok protein family has seven members (Dok-1-Dok-7). The Dok proteins share structural similarities characterized by the NH2-terminal pleckstrin homology and phosphotyrosine-binding domains followed by SH2 target motifs in the COOH-terminal moiety, indicating an adapter function. Indeed, Dok-1 was originally identified as a 62 kDa protein that binds with p120 rasGAP, a potent inhibitor of Ras, upon tyrosine phosphorylation by a variety of protein tyrosine kinases. Among the Dok family, only Dok-1, Dok-2, and Dok-3 are preferentially expressed in hematopoietic/immune cells. Dok-1 and its closest relative Dok-2 act as negative regulators of the Ras-Erk pathway downstream of many immunoreceptor-mediated signaling systems, and it is believed that recruitment of p120 rasGAP by Dok-1 and Dok-2 is critical to their negative regulation. By contrast, Dok-3 does not bind with p120 rasGAP. However, accumulating evidence has demonstrated that Dok-3 is a negative regulator of the activation of JNK and mobilization of Ca2+ in B-cell receptor-mediated signaling, where the interaction of Dok-3 with SHIP-1 and Grb2 appears to be important. Here, we review the physiological roles and underlying mechanisms of Dok family proteins.
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Affiliation(s)
- Ryuichi Mashima
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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Abstract
The growth factor receptor-bound protein 2 (Grb2) is a ubiquitously expressed and evolutionary conserved adapter protein possessing a plethora of described interaction partners for the regulation of signal transduction. In B lymphocytes, the Grb2-mediated scaffolding function controls the assembly and subcellular targeting of activating as well as inhibitory signalosomes in response to ligation of the antigen receptor. Also, integration of simultaneous signals from B-cell coreceptors that amplify or attenuate antigen receptor signal output relies on Grb2. Hence, Grb2 is an essential signal integrator. The key question remains, however, of how pathway specificity can be maintained during signal homeostasis critically required for the balance between immune cell activation and tolerance induction. Here, we summarize the molecular network of Grb2 in B cells and introduce a proteomic approach to elucidate the interactome of Grb2 in vivo.
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Affiliation(s)
- Konstantin Neumann
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
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Peng Q, Malhotra S, Torchia JA, Kerr WG, Coggeshall KM, Humphrey MB. TREM2- and DAP12-dependent activation of PI3K requires DAP10 and is inhibited by SHIP1. Sci Signal 2010; 3:ra38. [PMID: 20484116 DOI: 10.1126/scisignal.2000500] [Citation(s) in RCA: 264] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The activation and fusion of macrophages and of osteoclasts require the adaptor molecule DNAX-activating protein of 12 kD (DAP12), which contains immunoreceptor tyrosine-based activation motifs (ITAMs). TREM2 (triggering receptor expressed on myeloid cells-2) is the main DAP12-associated receptor in osteoclasts and, similar to DAP12 deficiency, loss of TREM2 in humans leads to Nasu-Hakola disease, which is characterized by bone cysts and dementia. Furthermore, in vitro experiments have shown that deficiency in DAP12 or TREM2 leads to impaired osteoclast development and the formation of mononuclear osteoclasts. Here, we demonstrate that the ligation of TREM2 activated phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase 1 (ERK1) and ERK2, and the guanine nucleotide exchange factor Vav3; induced the mobilization of intracellular calcium (Ca(2+)) and the reorganization of actin; and prevented apoptosis. The signaling adaptor molecule DAP10 played a key role in the TREM2- and DAP12-dependent recruitment of PI3K to the signaling complex. Src homology 2 (SH2) domain-containing inositol phosphatase-1 (SHIP1) inhibited TREM2- and DAP12-induced signaling by binding to DAP12 in an SH2 domain-dependent manner and preventing the recruitment of PI3K to DAP12. These results demonstrate a previously uncharacterized interaction of SHIP1 with DAP12 that functionally limits TREM2- and DAP12-dependent signaling and identify a mechanism through which SHIP1 regulates key ITAM-containing receptors by directly blocking the binding and activation of PI3K.
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Affiliation(s)
- Qisheng Peng
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Kroczek C, Lang C, Brachs S, Grohmann M, Dütting S, Schweizer A, Nitschke L, Feller SM, Jäck HM, Mielenz D. Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. THE JOURNAL OF IMMUNOLOGY 2010; 184:3665-76. [PMID: 20194721 DOI: 10.4049/jimmunol.0903642] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Compartmentalization of the BCR in membrane rafts is important for its signaling capacity. Swiprosin-1/EFhd2 (Swip-1) is an EF-hand and coiled-coil-containing adaptor protein with predicted Src homology 3 (SH3) binding sites that we identified in membrane rafts. We showed previously that Swip-1 amplifies BCR-induced apoptosis; however, the mechanism of this amplification was unknown. To address this question, we overexpressed Swip-1 and found that Swip-1 amplified the BCR-induced calcium flux in WEHI231, B62.1, and Bal17 cells. Conversely, the BCR-elicited calcium flux was strongly attenuated in Swip-1-silenced WEHI231 cells, and this was due to a decreased calcium mobilization from intracellular stores. Complementation of Swip-1 expression in Swip-1-silenced WEHI231 cells restored the BCR-induced calcium flux and enhanced spleen tyrosine kinase (Syk) tyrosine phosphorylation and activity as well as SLP65/BLNK/BASH and phospholipase C gamma2 (PLCgamma2) tyrosine phosphorylation. Furthermore, Swip-1 induced the constitutive association of the BCR itself, Syk, and PLCgamma2 with membrane rafts. Concomitantly, Swip-1 stabilized the association of BCR with tyrosine-phosphorylated proteins, specifically Syk and PLCgamma2, and enhanced the constitutive interaction of Syk and PLCgamma2 with Lyn. Interestingly, Swip-1 bound to the rSH3 domains of the Src kinases Lyn and Fgr, as well as to that of PLCgamma. Deletion of the predicted SH3-binding region in Swip-1 diminished its association and that of Syk and PLCgamma2 with membrane rafts, reduced its interaction with the SH3 domain of PLCgamma, and diminished the BCR-induced calcium flux. Hence, Swip-1 provides a membrane scaffold that is required for the Syk-, SLP-65-, and PLCgamma2-dependent BCR-induced calcium flux.
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Affiliation(s)
- Carmen Kroczek
- Division of Molecular Immunology, Department of Medicine III, Nikolaus Fiebiger Center, University of Erlangen-Nürnberg, Erlangen, Germany
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Miles RR, Mankey CC, Seiler CE, Smith LB, Teruya-Feldstein J, Hsi ED, Elenitoba-Johnson KS, Lim MS. Expression of Grb2 distinguishes classical Hodgkin lymphomas from primary mediastinal B-cell lymphomas and other diffuse large B-cell lymphomas. Hum Pathol 2009; 40:1731-7. [DOI: 10.1016/j.humpath.2009.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/20/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
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