1
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Zhou X, Ren T, Zan H, Hua C, Guo X. Novel Immune Checkpoints in Esophageal Cancer: From Biomarkers to Therapeutic Targets. Front Immunol 2022; 13:864202. [PMID: 35669786 PMCID: PMC9163322 DOI: 10.3389/fimmu.2022.864202] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/25/2022] [Indexed: 12/24/2022] Open
Abstract
Esophageal cancer ranks as the sixth most common cause of cancer death worldwide. Due to the limited efficacy of conventional therapeutic strategies, including surgery, chemotherapy, and radiotherapy, treatments are still far from satisfactory in terms of survival, prompting the search for novel treatment methods. Immune checkpoints play crucial roles in immune evasion mediated by tumor cells, and successful clinical outcomes have been achieved via blocking these pathways. However, only a small fraction of patients can benefit from current immune checkpoint inhibitors targeting programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated protein-4. Unfortunately, some patients show primary and/or acquired resistance to immune checkpoint inhibitors. Until now, novel immune checkpoint pathways have rarely been studied in esophageal cancer, and there is a great need for biomarkers to predict who will benefit from existing strategies. Herein, we primarily discuss the roles of new immune checkpoints as predictive biomarkers and therapeutic targets for esophageal cancer. In addition, we summarize the ongoing clinical trials and provide future research directions targeting these pathways.
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Affiliation(s)
- Xueyin Zhou
- School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Ting Ren
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Hongyuan Zan
- School of Medicine, Wenzhou Medical University, Wenzhou, China
| | - Chunyan Hua
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Chunyan Hua, ; Xufeng Guo,
| | - Xufeng Guo
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Chunyan Hua, ; Xufeng Guo,
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2
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Borowicz P, Sundvold V, Chan H, Abrahamsen G, Kjelstrup H, Nyman TA, Spurkland A. Tyr 192 Regulates Lymphocyte-Specific Tyrosine Kinase Activity in T Cells. THE JOURNAL OF IMMUNOLOGY 2021; 207:1128-1137. [PMID: 34321230 DOI: 10.4049/jimmunol.2001105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 06/07/2021] [Indexed: 11/19/2022]
Abstract
TCR signaling critically depends on the tyrosine kinase Lck (lymphocyte-specific protein tyrosine kinase). Two phosphotyrosines, the activating pTyr394 and the inhibitory pTyr505, control Lck activity. Recently, pTyr192 in the Lck SH2 domain emerged as a third regulator. How pTyr192 may affect Lck function remains unclear. In this study, we explored the role of Lck Tyr192 using CRISPR/Cas9-targeted knock-in mutations in the human Jurkat T cell line. Our data reveal that both Lck pTyr394 and pTyr505 are controlled by Lck Tyr192 Lck with a nonphosphorylated SH2 domain (Lck Phe192) displayed hyperactivity, possibly by promoting Lck Tyr394 transphosphorylation. Lck Glu192 mimicking stable Lck pTyr192 was inhibited by Tyr505 hyperphosphorylation. To overcome this effect, we further mutated Tyr505 The resulting Lck Glu192/Phe505 displayed strongly increased amounts of pTyr394 both in resting and activated T cells. Our results suggest that a fundamental role of Lck pTyr192 may be to protect Lck pTyr394 and/or pTyr505 to maintain a pool of already active Lck in resting T cells. This provides an additional mechanism for fine-tuning of Lck as well as T cell activity.
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Affiliation(s)
- Paweł Borowicz
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
| | - Vibeke Sundvold
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
| | - Hanna Chan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
| | - Greger Abrahamsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
| | - Hanna Kjelstrup
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Anne Spurkland
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; and
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3
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Strazza M, Azoulay-Alfaguter I, Peled M, Adam K, Mor A. Transmembrane adaptor protein PAG is a mediator of PD-1 inhibitory signaling in human T cells. Commun Biol 2021; 4:672. [PMID: 34083754 PMCID: PMC8175585 DOI: 10.1038/s42003-021-02225-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/29/2021] [Indexed: 12/15/2022] Open
Abstract
The inhibitory receptor PD-1 is expressed on T cells to inhibit select functions when ligated. The complete signaling mechanism downstream of PD-1 has yet to be uncovered. Here, we discovered phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG) is phosphorylated following PD-1 ligation and associate this with inhibitory T cell function. Clinical cohort analysis correlates low PAG expression with increased survival from numerous tumor types. PAG knockdown in T cells prevents PD-1-mediated inhibition of cytokine secretion, cell adhesion, CD69 expression, and ERK204/187 phosphorylation, and enhances phosphorylation of SRC527 following PD-1 ligation. PAG overexpression rescues these effects. In vivo, PAG contributes greatly to the growth of two murine tumors, MC38 and B16, and limits T cell presence within the tumor. Moreover, PAG deletion sensitizes tumors to PD-1 blockade. Here PAG is established as a critical mediator of PD-1 signaling and as a potential target to enhance T cell activation in tumors.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Cell Line, Tumor
- Cells, Cultured
- Cytokines/metabolism
- Humans
- Lectins, C-Type/metabolism
- Lymphocyte Activation
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Phosphorylation
- Programmed Cell Death 1 Receptor/genetics
- Programmed Cell Death 1 Receptor/metabolism
- Signal Transduction
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Mice
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Affiliation(s)
- Marianne Strazza
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA
| | | | - Michael Peled
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY, USA
| | - Kieran Adam
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA
| | - Adam Mor
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY, USA.
- Division of Rheumatology, Department of Medicine, Columbia University Medical Center, New York, NY, USA.
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4
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Yamagishi M, Hori M, Fujikawa D, Ohsugi T, Honma D, Adachi N, Katano H, Hishima T, Kobayashi S, Nakano K, Nakashima M, Iwanaga M, Utsunomiya A, Tanaka Y, Okada S, Tsukasaki K, Tobinai K, Araki K, Watanabe T, Uchimaru K. Targeting Excessive EZH1 and EZH2 Activities for Abnormal Histone Methylation and Transcription Network in Malignant Lymphomas. Cell Rep 2020; 29:2321-2337.e7. [PMID: 31747604 DOI: 10.1016/j.celrep.2019.10.083] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/08/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022] Open
Abstract
Although global H3K27me3 reprogramming is a hallmark of cancer, no effective therapeutic strategy for H3K27me3-high malignancies harboring EZH2WT/WT has yet been established. We explore epigenome and transcriptome in EZH2WT/WT and EZH2WT/Mu aggressive lymphomas and show that mutual interference and compensatory function of co-expressed EZH1 and EZH2 rearrange their own genome-wide distribution, thereby establishing restricted chromatin and gene expression signatures. Direct comparison of leading compounds introduces potency and a mechanism of action of the EZH1/2 dual inhibitor (valemetostat). The synthetic lethality is observed in all lymphoma models and primary adult T cell leukemia-lymphoma (ATL) cells. Opposing actions of EZH1/2-polycomb and SWI/SNF complexes are required for facultative heterochromatin formation. Inactivation of chromatin-associated genes (ARID1A, SMARCA4/BRG1, SMARCB1/SNF5, KDM6A/UTX, BAP1, KMT2D/MLL2) and oncovirus infection (HTLV-1, EBV) trigger EZH1/2 perturbation and H3K27me3 deposition. Our study provides the mechanism-based rationale for chemical dual targeting of EZH1/2 in cancer epigenome.
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Affiliation(s)
- Makoto Yamagishi
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
| | - Makoto Hori
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Dai Fujikawa
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Takeo Ohsugi
- Department of Laboratory Animal Science, School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, Japan
| | - Daisuke Honma
- Oncology Laboratories, Daiichi Sankyo, Co., Tokyo, Japan
| | | | - Harutaka Katano
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tsunekazu Hishima
- Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan
| | - Seiichiro Kobayashi
- Division of Molecular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kazumi Nakano
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Makoto Nakashima
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Masako Iwanaga
- Department of Clinical Epidemiology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Atae Utsunomiya
- Department of Hematology, Imamura General Hospital, Kagoshima, Japan
| | - Yuetsu Tanaka
- Graduate School and Faculty of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Seiji Okada
- Joint Research Center for Human Retrovirus Infection, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kunihiro Tsukasaki
- Department of Hematology, International Medical Center, Saitama Medical University, Saitama, Japan
| | - Kensei Tobinai
- Department of Hematology, National Cancer Center Hospital, Tokyo, Japan
| | - Kazushi Araki
- Oncology Clinical Development Department, Daiichi Sankyo Co., Tokyo, Japan
| | | | - Kaoru Uchimaru
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
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5
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Ullah MA, Vicente CT, Collinson N, Curren B, Sikder MAA, Sebina I, Simpson J, Varelias A, Lindquist JA, Ferreira MAR, Phipps S. PAG1 limits allergen-induced type 2 inflammation in the murine lung. Allergy 2020; 75:336-345. [PMID: 31321783 DOI: 10.1111/all.13991] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/30/2019] [Accepted: 06/24/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND Phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG1) is a transmembrane adaptor protein that affects immune receptor signaling in T and B cells. Evidence from genome-wide association studies of asthma suggests that genetic variants that regulate the expression of PAG1 are associated with asthma risk. However, it is not known whether PAG1 expression is causally related to asthma pathophysiology. Here, we investigated the role of PAG1 in a preclinical mouse model of house dust mite (HDM)-induced allergic sensitization and allergic airway inflammation. METHODS Pag1-deficient (Pag1-/- ) and wild-type (WT) mice were sensitized or sensitized/challenged to HDM, and hallmark features of allergic inflammation were assessed. The contribution of T cells was assessed through depletion (anti-CD4 antibody) and adoptive transfer studies. RESULTS Type 2 inflammation (eosinophilia, eotaxin-2 expression, IL-4/IL-5/IL-13 production, mucus production) in the airways and lungs was significantly increased in HDM sensitized/challenged Pag1-/- mice compared to WT mice. The predisposition to allergic sensitization was associated with increased airway epithelial high-mobility group box 1 (HMGB1) translocation and release, increased type 2 innate lymphoid cells (ILC2s) and monocyte-derived dendritic cell numbers in the mediastinal lymph nodes, and increased T-helper type 2 (TH 2)-cell differentiation. CD4+ T-cell depletion studies or the adoptive transfer of WT OVA-specific CD4+ T cells to WT or Pag1-/- recipients demonstrated that the heightened propensity for TH 2-cell differentiation was both T cell intrinsic and extrinsic. CONCLUSION PAG1 deficiency increased airway epithelial activation, ILC2 expansion, and TH 2 differentiation. As a consequence, PAG1 deficiency predisposed toward allergic sensitization and increased the severity of experimental asthma.
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Affiliation(s)
- Md Ashik Ullah
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | - Cristina T. Vicente
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | | | - Bodie Curren
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | - Md Al Amin Sikder
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | - Ismail Sebina
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
| | - Jennifer Simpson
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | - Antiopi Varelias
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
| | - Jonathan A. Lindquist
- Clinic for Nephrology and Hypertension, Diabetology and Endocrinology Otto‐von‐Guericke University Magdeburg Germany
| | | | - Simon Phipps
- QIMR Berghofer Medical Research Institute Brisbane Qld Australia
- Faculty of Medicine University of Queensland Brisbane Qld Australia
- Australian Infectious Diseases Research Centre University of Queensland Brisbane Qld Australia
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6
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Agarwal S, Ghosh R, Chen Z, Lakoma A, Gunaratne PH, Kim ES, Shohet JM. Transmembrane adaptor protein PAG1 is a novel tumor suppressor in neuroblastoma. Oncotarget 2018; 7:24018-26. [PMID: 26993602 PMCID: PMC5029681 DOI: 10.18632/oncotarget.8116] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 03/01/2016] [Indexed: 02/06/2023] Open
Abstract
(NB) is the most common extracranial pediatric solid tumor with high mortality rates. The tyrosine kinase c-Src has been known to play an important role in differentiation of NB cells, but the mechanism of c-Src regulation has not been defined. Here, we characterize PAG1 (Cbp, Csk binding protein), a central inhibitor of c-Src and other Src family kinases, as a novel tumor suppressor in NB. Clinical cohort analysis demonstrate that low expression of PAG1 is a significant prognostic factor for high stage disease, increased relapse, and worse overall survival for children with NB. PAG1 knockdown in NB cells promotes proliferation and anchorage-independent colony formation with increased activation of AKT and ERK downstream of c-Src, while PAG1 overexpression significantly rescues these effects. In vivo, PAG1 overexpression significantly inhibits NB tumorigenicity in an orthotopic xenograft model. Our results establish PAG1 as a potent tumor suppressor in NB by inhibiting c-Src and downstream effector pathways. Thus, reactivation of PAG1 and inhibition of c-Src kinase activity represents an important novel therapeutic approach for high-risk NB.
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Affiliation(s)
- Saurabh Agarwal
- Department of Pediatrics, Section of Hematology-Oncology, Texas Children's Cancer Center, and Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Rajib Ghosh
- Department of Biology & Biochemistry, University of Houston, Houston, Texas 77204, USA
| | - Zaowen Chen
- Department of Pediatrics, Section of Hematology-Oncology, Texas Children's Cancer Center, and Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Anna Lakoma
- Michael E. DeBakey, Department of Surgery, Division of Pediatric Surgery, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Preethi H Gunaratne
- Department of Biology & Biochemistry, University of Houston, Houston, Texas 77204, USA
| | - Eugene S Kim
- Michael E. DeBakey, Department of Surgery, Division of Pediatric Surgery, Baylor College of Medicine, Houston, Texas 77030, USA.,Department of Surgery, Division of Pediatric Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California 90027, USA
| | - Jason M Shohet
- Department of Pediatrics, Section of Hematology-Oncology, Texas Children's Cancer Center, and Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA
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7
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Anderson AC, Joller N, Kuchroo VK. Lag-3, Tim-3, and TIGIT: Co-inhibitory Receptors with Specialized Functions in Immune Regulation. Immunity 2017; 44:989-1004. [PMID: 27192565 DOI: 10.1016/j.immuni.2016.05.001] [Citation(s) in RCA: 1406] [Impact Index Per Article: 200.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 12/14/2022]
Abstract
Co-inhibitory receptors, such as CTLA-4 and PD-1, have an important role in regulating T cell responses and have proven to be effective targets in the setting of chronic diseases where constitutive co-inhibitory receptor expression on T cells dampens effector T cell responses. Unfortunately, many patients still fail to respond to therapies that target CTLA-4 and PD-1. The next wave of co-inhibitory receptor targets that are being explored in clinical trials include Lag-3, Tim-3, and TIGIT. These receptors, although they belong to the same class of receptors as PD-1 and CTLA-4, exhibit unique functions, especially at tissue sites where they regulate distinct aspects of immunity. Increased understanding of the specialized functions of these receptors will inform the rational application of therapies that target these receptors to the clinic.
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Affiliation(s)
- Ana C Anderson
- Evergrande Center for Immunologic Diseases and Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Nicole Joller
- Institute of Experimental Immunology, University of Zürich, Zürich 8057, Switzerland
| | - Vijay K Kuchroo
- Evergrande Center for Immunologic Diseases and Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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8
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Weir ME, Mann JE, Corwin T, Fulton ZW, Hao JM, Maniscalco JF, Kenney MC, Roman Roque KM, Chapdelaine EF, Stelzl U, Deming PB, Ballif BA, Hinkle KL. Novel autophosphorylation sites of Src family kinases regulate kinase activity and SH2 domain-binding capacity. FEBS Lett 2016; 590:1042-52. [PMID: 27001024 DOI: 10.1002/1873-3468.12144] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/18/2016] [Accepted: 03/17/2016] [Indexed: 01/10/2023]
Abstract
Src family tyrosine kinases (SFKs) are critical players in normal and aberrant biological processes. While phosphorylation importantly regulates SFKs at two known tyrosines, large-scale phosphoproteomics have revealed four additional tyrosines commonly phosphorylated in SFKs. We found these novel tyrosines to be autophosphorylation sites. Mimicking phosphorylation at the C-terminal site to the activation loop decreased Fyn activity. Phosphomimetics and direct phosphorylation at the three SH2 domain sites increased Fyn activity while reducing phosphotyrosine-dependent interactions. While 68% of human SH2 domains exhibit conservation of at least one of these tyrosines, few have been found phosphorylated except when found in cis to a kinase domain.
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Affiliation(s)
- Marion E Weir
- Department of Biology, University of Vermont, Burlington, VT, USA
| | - Jacqueline E Mann
- Department of Medical Laboratory and Radiation Sciences, University of Vermont, Burlington, VT, USA
| | - Thomas Corwin
- Otto-Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Zachary W Fulton
- Department of Biology, University of Vermont, Burlington, VT, USA.,Department of Biology and Physical Education, Norwich University, Northfield, VT, USA
| | - Jennifer M Hao
- Department of Biology, University of Vermont, Burlington, VT, USA
| | | | - Marie C Kenney
- Department of Biology, University of Vermont, Burlington, VT, USA
| | | | - Elizabeth F Chapdelaine
- Department of Biology, University of Vermont, Burlington, VT, USA.,Department of Biology and Physical Education, Norwich University, Northfield, VT, USA
| | - Ulrich Stelzl
- Otto-Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Paula B Deming
- Department of Medical Laboratory and Radiation Sciences, University of Vermont, Burlington, VT, USA
| | - Bryan A Ballif
- Department of Biology, University of Vermont, Burlington, VT, USA
| | - Karen L Hinkle
- Department of Biology, University of Vermont, Burlington, VT, USA.,Department of Biology and Physical Education, Norwich University, Northfield, VT, USA
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9
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Granum S, Sundvold-Gjerstad V, Gopalakrishnan RP, Berge T, Koll L, Abrahamsen G, Sorlie M, Spurkland A. The kinase Itk and the adaptor TSAd change the specificity of the kinase Lck in T cells by promoting the phosphorylation of Tyr192. Sci Signal 2014; 7:ra118. [DOI: 10.1126/scisignal.2005384] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Rolland D, Basrur V, Conlon K, Wolfe T, Fermin D, Nesvizhskii AI, Lim MS, Elenitoba-Johnson KSJ. Global phosphoproteomic profiling reveals distinct signatures in B-cell non-Hodgkin lymphomas. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1331-42. [PMID: 24667141 DOI: 10.1016/j.ajpath.2014.01.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/05/2013] [Accepted: 01/02/2014] [Indexed: 12/23/2022]
Abstract
Deregulation of signaling pathways controlled by protein phosphorylation underlies the pathogenesis of hematological malignancies; however, the extent to which deregulated phosphorylation may be involved in B-cell non-Hodgkin lymphoma (B-NHL) pathogenesis is largely unknown. To identify phosphorylation events important in B-NHLs, we performed mass spectrometry-based, label-free, semiquantitative phosphoproteomic profiling of 11 cell lines derived from three B-NHL categories: Burkitt lymphoma, follicular lymphoma, and mantle-cell lymphoma. In all, 6579 unique phosphopeptides, corresponding to 1701 unique phosphorylated proteins, were identified and quantified. The data are available via ProteomeXchange with identifier PXD000658. Hierarchical clustering highlighted distinct phosphoproteomic signatures associated with each lymphoma subtype. Interestingly, germinal center-derived B-NHL cell lines were characterized by phosphorylation of proteins involved in the B-cell receptor signaling. Of these proteins, phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG1) was identified with the most phosphorylated tyrosine peptides in Burkitt lymphoma and follicular lymphoma. PAG1 knockdown resulted in perturbation of the tyrosine phosphosignature of B-cell receptor signaling components. Significantly, PAG1 knockdown increased cell proliferation and response to antigen stimulation of these germinal center-derived B-NHLs. These data provide a detailed annotation of phosphorylated proteins in human lymphoid cancer. Overall, our study revealed the utility of unbiased phosphoproteome interrogation in characterizing signaling networks that may provide insights into pathogenesis mechanisms in B-cell lymphomas.
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Affiliation(s)
- Delphine Rolland
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Kevin Conlon
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Thomas Wolfe
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Damian Fermin
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Alexey I Nesvizhskii
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Megan S Lim
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan; Center for Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Kojo S J Elenitoba-Johnson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan; Center for Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan; Center for Protein Folding Disease, University of Michigan Medical School, Ann Arbor, Michigan.
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11
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Chapman NM, Connolly SF, Reinl EL, Houtman JCD. Focal adhesion kinase negatively regulates Lck function downstream of the T cell antigen receptor. THE JOURNAL OF IMMUNOLOGY 2013; 191:6208-21. [PMID: 24227778 DOI: 10.4049/jimmunol.1301587] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Focal adhesion kinase (FAK) is a critical regulator of signal transduction in multiple cell types. Although this protein is activated upon TCR engagement, the cellular function that FAK plays in mature human T cells is unknown. By suppressing the function of FAK, we revealed that FAK inhibits TCR-mediated signaling by recruiting C-terminal Src kinase to the membrane and/or receptor complex following TCR activation. Thus, in the absence of FAK, the inhibitory phosphorylation of Lck and/or Fyn is impaired. Together, these data highlight a novel role for FAK as a negative regulator TCR function in human T cells. These results also suggest that changes in FAK expression could modulate sensitivity to TCR stimulation and contribute to the progression of T cell malignancies and autoimmune diseases.
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Affiliation(s)
- Nicole M Chapman
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA 52242
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12
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Hrdinka M, Horejsi V. PAG - a multipurpose transmembrane adaptor protein. Oncogene 2013; 33:4881-92. [DOI: 10.1038/onc.2013.485] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/25/2013] [Accepted: 09/25/2013] [Indexed: 12/25/2022]
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13
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Brownlie RJ, Zamoyska R. T cell receptor signalling networks: branched, diversified and bounded. Nat Rev Immunol 2013; 13:257-69. [PMID: 23524462 DOI: 10.1038/nri3403] [Citation(s) in RCA: 333] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Engagement of antigen-specific T cell receptors (TCRs) is a prerequisite for T cell activation. Acquisition of appropriate effector T cell function requires the participation of multiple signals from the T cell microenvironment. Trying to understand how these signals integrate to achieve specific functional outcomes while maintaining tolerance to self is a major challenge in lymphocyte biology. Several recent publications have provided important insights into how dysregulation of T cell signalling and the development of autoreactivity can result if the branching and integration of signalling pathways are perturbed. We discuss how these findings highlight the importance of spatial segregation of individual signalling components as a way of regulating T cell responsiveness and immune tolerance.
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Affiliation(s)
- Rebecca J Brownlie
- Institute for Immunology and Infection Research, The University of Edinburgh, Edinburgh EH9 3JT, UK
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14
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Smida M, Cammann C, Gurbiel S, Kerstin N, Lingel H, Lindquist S, Simeoni L, Brunner-Weinzierl MC, Suchanek M, Schraven B, Lindquist JA. PAG/Cbp suppression reveals a contribution of CTLA-4 to setting the activation threshold in T cells. Cell Commun Signal 2013; 11:28. [PMID: 23601194 PMCID: PMC3763844 DOI: 10.1186/1478-811x-11-28] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 04/03/2013] [Indexed: 11/12/2022] Open
Abstract
Background PAG/Cbp represents a ubiquitous mechanism for regulating Src family kinases
by recruiting Csk to the plasma membrane, thereby controlling cellular
activation. Since Src kinases are known oncogenes, we used RNA interference
in primary human T cells to test whether the loss of PAG resulted in
lymphocyte transformation. Results PAG-depletion enhanced Src kinase activity and augmented proximal T-cell
receptor signaling; exactly the phenotype expected for loss of this negative
regulator. Surprisingly, rather than becoming hyper-proliferative,
PAG-suppressed T cells became unresponsive. This was mediated by a
Fyn-dependent hyper-phosphorylation of the inhibitory receptor CTLA-4, which
recruited the protein tyrosine phosphatase Shp-1 to lipid rafts.
Co-suppression of CTLA-4 abrogates this inhibition and restores
proliferation to T cells. Conclusion We have identified a fail-safe mechanism as well as a novel contribution of
CTLA-4 to setting the activation threshold in T cells.
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Affiliation(s)
- Michal Smida
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Leipziger Strasse 44, Magdeburg, 39120, Germany.
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15
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Filipp D, Ballek O, Manning J. Lck, Membrane Microdomains, and TCR Triggering Machinery: Defining the New Rules of Engagement. Front Immunol 2012; 3:155. [PMID: 22701458 PMCID: PMC3372939 DOI: 10.3389/fimmu.2012.00155] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 05/25/2012] [Indexed: 11/21/2022] Open
Abstract
In spite of a comprehensive understanding of the schematics of T cell receptor (TCR) signaling, the mechanisms regulating compartmentalization of signaling molecules, their transient interactions, and rearrangement of membrane structures initiated upon TCR engagement remain an outstanding problem. These gaps in our knowledge are exemplified by recent data demonstrating that TCR triggering is largely dependent on a preactivated pool of Lck concentrated in T cells in a specific type of membrane microdomains. Our current model posits that in resting T cells all critical components of TCR triggering machinery including TCR/CD3, Lck, Fyn, CD45, PAG, and LAT are associated with distinct types of lipid-based microdomains which represent the smallest structural and functional units of membrane confinement able to negatively control enzymatic activities and substrate availability that is required for the initiation of TCR signaling. In addition, the microdomains based segregation spatially limits the interaction of components of TCR triggering machinery prior to the onset of TCR signaling and allows their rapid communication and signal amplification after TCR engagement, via the process of their coalescence. Microdomains mediated compartmentalization thus represents an essential membrane organizing principle in resting T cells. The integration of these structural and functional aspects of signaling into a unified model of TCR triggering will require a deeper understanding of membrane biology, novel interdisciplinary approaches and the generation of specific reagents. We believe that the fully integrated model of TCR signaling must be based on membrane structural network which provides a proper environment for regulatory processes controlling TCR triggering.
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Affiliation(s)
- Dominik Filipp
- Laboratory of Immunobiology, Institute of Molecular Genetics AS CR Prague, Czech Republic
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16
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Yu W, Wang Y, Gong M, Pei F, Zheng J. Phosphoprotein associated with glycosphingolipid microdomains 1 inhibits the proliferation and invasion of human prostate cancer cells in vitro through suppression of Ras activation. Oncol Rep 2012; 28:606-14. [PMID: 22664862 DOI: 10.3892/or.2012.1848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 03/26/2012] [Indexed: 11/06/2022] Open
Abstract
Phosphoprotein associated with glycosphingolipid microdomains 1 (PAG) is an important negative regulator of immune signaling in T lymphocytes. However, newly emerging evidence has indicated that PAG may play important roles in tumor cells. Our previously reported cDNA microarray experiments identified PAG as a gene down-regulated in the high metastatic potential prostate cancer cell line PC-3M-1E8. In this study, we investigated the role of PAG in the proliferation, invasion and metastasis of prostate cancer cells and the underlying mechanisms. We confirmed that the expression of PAG at both the mRNA and protein levels was low in PC-3M-1E8 and DU145 cells compared to low metastatic potential prostate cancer cells PC-3M-2B4. In addition, we demonstrated that the reintroduction of PAG to PC-3M-1E8 and DU145 cells led to reduced proliferation through cell cycle arrest, decreased anchorage-independent growth and reduced invasion ability of tumor cells in vitro. This is the first report demonstrating that PAG inhibits the proliferation and invasion potential of prostate cancer cells via the interaction with RasGAP to recruit RasGAP to the cell membrane, where RasGAP hydrolyzes GTP to GDP, reduces the level of activated Ras, and ultimately suppresses the activation of ERK1/2, cyclin D1 and other effectors of the Ras signaling pathway. Morphologically, we observed that PAG could diminish the formation of pseudopodia on the cell surface and redistribute the intracellular F-actin in PC-3M-1E8 cells, which directly leads to the decreased invasion and metastasis potential of tumor cells. Taken together, these results suggest that PAG acts to inhibit the development and metastasis of prostate cancers and represents a novel therapeutic target for prostate cancer.
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Affiliation(s)
- Wenjuan Yu
- Department of Pathology, The Affiliated Hospital of Medical College, Qingdao University, Qingdao, PR China
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17
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Ingley E. Integrating novel signaling pathways involved in erythropoiesis. IUBMB Life 2012; 64:402-10. [PMID: 22431075 DOI: 10.1002/iub.1024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 02/14/2012] [Indexed: 12/17/2022]
Abstract
Many extrinsic and intrinsic factors control the development of red blood cells from committed progenitors, with the Erythropoietin-receptor (Epo-R) signaling network being the primary controlling molecular hub. Although much is understood about erythroid signaling pathways, new and intriguing factors that influence different aspects of erythroid cell development are still being uncovered. New extrinsic effectors include hypoxia and polymeric IgA1 (pIgA1), and new Epo-R signaling pathway components include Lyn/Cbp and Lyn/Liar. Hypoxia directly activates committed erythroid progenitors to expand, whereas pIgA1 activates the Akt and MAP-Kinase (MAPK) pathways through transferrin receptors on more mature erythroid cells. The Lyn/Cbp pathway controls the activity and protein levels of Lyn through recruitment of Csk and SOCS1, as well as feeding into the control of other pathways mediated by recruitment of ras-GAP, PI3-kinase, PLCγ, Fes, and EBP50. Nuclear/cytoplasmic shuttling of Lyn and other signaling molecules is influenced by Liar and results in regulation of their intersecting signaling pathways. The challenge of future research is to flesh out the details of these new signaling regulators/networks and integrate their influences during the different stages of erythropoiesis.
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Affiliation(s)
- Evan Ingley
- Cell Signalling Group, Western Australian Institute for Medical Research, Centre for Medical Research and The University of Western Australia, Perth, WA, Australia.
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18
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Targeting Lyn tyrosine kinase through protein fusions encompassing motifs of Cbp (Csk-binding protein) and the SOCS box of SOCS1. Biochem J 2012; 442:611-20. [DOI: 10.1042/bj20111485] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The tyrosine kinase Lyn is involved in oncogenic signalling in several leukaemias and solid tumours, and we have previously identified a pathway centred on Cbp [Csk (C-terminal Src kinase)-binding protein] that mediates both enzymatic inactivation, as well as proteasomal degradation of Lyn via phosphorylation-dependent recruitment of Csk (responsible for phosphorylating the inhibitory C-terminal tyrosine of Lyn) and SOCS1 (suppressor of cytokine signalling 1; an E3 ubiquitin ligase). In the present study we show that fusing specific functional motifs of Cbp and domains of SOCS1 together generates a novel molecule capable of directing the proteasomal degradation of Lyn. We have characterized the binding of pY (phospho-tyrosine) motifs of Cbp to SFK (Src-family kinase) SH2 (Src homology 2) domains, identifying those with high affinity and specificity for the SH2 domain of Lyn and that are preferred substrates of active Lyn. We then fused them to the SB (SOCS box) of SOCS1 to facilitate interaction with the ubiquitination-promoting elongin B/C complex. As an eGFP (enhanced green fluorescent protein) fusion, these proteins can direct the polyubiquitination and proteasomal degradation of active Lyn. Expressing this fusion protein in DU145 cancer cells (but not LNCaP or MCF-7 cells), that require Lyn signalling for survival, promotes loss of Lyn, loss of caspase 3, appearance of an apoptotic morphology and failure to survive/expand. These findings show how functional domains of Cbp and SOCS1 can be fused together to generate molecules capable of inhibiting the growth of cancer cells that express high levels of active Lyn.
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19
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Wang PS, Wang J, Zheng Y, Pallen CJ. Loss of protein-tyrosine phosphatase α (PTPα) increases proliferation and delays maturation of oligodendrocyte progenitor cells. J Biol Chem 2012; 287:12529-40. [PMID: 22354965 DOI: 10.1074/jbc.m111.312769] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Tightly controlled termination of proliferation determines when oligodendrocyte progenitor cells (OPCs) can initiate differentiation and mature into myelin-forming cells. Protein-tyrosine phosphatase α (PTPα) promotes OPC differentiation, but its role in proliferation is unknown. Here we report that loss of PTPα enhanced in vitro proliferation and survival and decreased cell cycle exit and growth factor dependence of OPCs but not neural stem/progenitor cells. PTPα(-/-) mice have more oligodendrocyte lineage cells in embryonic forebrain and delayed OPC maturation. On the molecular level, PTPα-deficient mouse OPCs and rat CG4 cells have decreased Fyn and increased Ras, Cdc42, Rac1, and Rho activities, and reduced expression of the Cdk inhibitor p27Kip1. Moreover, Fyn was required to suppress Ras and Rho and for p27Kip1 accumulation, and Rho inhibition in PTPα-deficient cells restored expression of p27Kip1. We propose that PTPα-Fyn signaling negatively regulates OPC proliferation by down-regulating Ras and Rho, leading to p27Kip1 accumulation and cell cycle exit. Thus, PTPα acts in OPCs to limit self-renewal and facilitate differentiation.
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Affiliation(s)
- Pei-Shan Wang
- Department of Pathology, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
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20
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Ballek O, Broučková A, Manning J, Filipp D. A specific type of membrane microdomains is involved in the maintenance and translocation of kinase active Lck to lipid rafts. Immunol Lett 2012; 142:64-74. [PMID: 22281390 DOI: 10.1016/j.imlet.2012.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 01/10/2012] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
Abstract
Lck is the principal signal-generating tyrosine kinase of the T cell activation mechanism. We have previously demonstrated that induced Lck activation outside of lipid rafts (LR) results in the rapid translocation of a fraction of Lck to LR. While this translocation predicates the subsequent production of IL-2, the mechanism underpinning this process is unknown. Here, we describe the main attributes of this translocating pool of Lck. Using fractionation of Brij58 lysates, derived from primary naive non-activated CD4(+) T cells, we show that a significant portion of Lck is associated with high molecular weight complexes representing a special type of detergent-resistant membranes (DRMs) of relatively high density and sensitivity to laurylmaltoside, thus called heavy DRMs. TcR/CD4 coaggregation-mediated activation resulted in the redistribution of more than 50% of heavy DRM-associated Lck to LR in a microtubular network-dependent fashion. Remarkably, in non-activated CD4(+) T-cells, only heavy DRM-associated Lck is phosphorylated on its activatory tyrosine 394 and this pool of Lck is found to be membrane confined with CD45 phosphatase. These data are the first to illustrate a lipid microdomain-based mechanism concentrating the preactivated pool of cellular Lck and supporting its high stoichiometry of colocalization with CD45 in CD4(+) T cells. They also provide a new structural framework to assess the mechanism underpinning the compartmentalization of critical signaling elements and regulation of spatio-temporal delivery of Lck function during the T cell proximal signaling.
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Affiliation(s)
- Ondřej Ballek
- Laboratory of Immunobiology, Institute of Molecular Genetics AS CR, Prague, Czech Republic
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21
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Fuller DM, Zhu M, Ou-Yang CW, Sullivan SA, Zhang W. A tale of two TRAPs: LAT and LAB in the regulation of lymphocyte development, activation, and autoimmunity. Immunol Res 2011; 49:97-108. [PMID: 21136199 DOI: 10.1007/s12026-010-8197-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transmembrane adaptor proteins (TRAPs) link antigen receptor engagement to downstream cellular processes. Although these proteins typically lack intrinsic enzymatic activity, they are phosphorylated on multiple tyrosine residues following lymphocyte activation, allowing them to function as scaffolds for the assembly of multi-molecular signaling complexes. Among the many TRAPs that have been discovered in recent years, the LAT (linker for activation of T cells) family of adaptor proteins plays an important role in the positive and negative regulation of lymphocyte maturation, activation, and differentiation. Of the two members in this family, LAT is an indispensable component controlling T cell and mast cell activation and function; LAB (linker for activation of B cells), also called NTAL, is necessary to fine-tune lymphocyte activation and may be a key regulator of innate immune responses. Here, we review recent advances on the function of LAT and LAB in the regulation of development and activation of immune cells.
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Affiliation(s)
- Deirdre M Fuller
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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22
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Lindquist S, Karitkina D, Langnaese K, Posevitz-Fejfar A, Schraven B, Xavier R, Seed B, Lindquist JA. Phosphoprotein associated with glycosphingolipid-enriched microdomains differentially modulates SRC kinase activity in brain maturation. PLoS One 2011; 6:e23978. [PMID: 21915273 PMCID: PMC3167820 DOI: 10.1371/journal.pone.0023978] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 08/02/2011] [Indexed: 12/19/2022] Open
Abstract
Src family kinases (SFK) control multiple processes during brain development and function. We show here that the phosphoprotein associated with glycosphigolipid-enriched microdomains (PAG)/Csk binding protein (Cbp) modulates SFK activity in the brain. The timing and localization of PAG expression overlap with Fyn and Src, both of which we find associated to PAG. We demonstrate in newborn (P1) mice that PAG negatively regulates Src family kinases (SFK). P1 Pag1-/- mouse brains show decreased recruitment of Csk into lipid rafts, reduced phosphorylation of the inhibitory tyrosines within SFKs, and an increase in SFK activity of >/ = 50%. While in brain of P1 mice, PAG and Csk are highly and ubiquitously expressed, little Csk is found in adult brain suggesting altered modes of SFK regulation. In adult brain Pag1-deficiency has no effect upon Csk-distribution or inhibitory tyrosine phosphorylation, but kinase activity is now reduced (−20–30%), pointing to the development of a compensatory mechanism that may involve PSD93. The distribution of the Csk-homologous kinase CHK is not altered. Importantly, since the activities of Fyn and Src are decreased in adult Pag1-/- mice, thus presenting the reversed phenotype of P1, this provides the first in vivo evidence for a Csk-independent positive regulatory function for PAG in the brain.
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Affiliation(s)
- Sabine Lindquist
- Department of Neurology, Hannover Medical School, Hannover, Germany.
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23
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Locatelli A, Lange CA. Met receptors induce Sam68-dependent cell migration by activation of alternate extracellular signal-regulated kinase family members. J Biol Chem 2011; 286:21062-72. [PMID: 21489997 DOI: 10.1074/jbc.m110.211409] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The hepatocyte growth factor (HGF)/Met receptor signaling pathway is deregulated in diverse human malignancies and plays a central role in oncogenesis, tumor progression, and invasive cancer growth. Similarly, altered expression and splicing (i.e. inclusion of variant exon 5, "v5") of the cell adhesion marker, CD44, is associated with advanced cancer phenotypes. We sought to further understand how HGF regulates CD44v5 expression. Immortalized nontumorigenic keratinocyte (HaCaT) cells abundantly express both Met receptors and CD44v5 transmembrane glycoproteins. HGF stimulated CD44v5 protein expression and HaCaT cell migration; these events required activation of the ERK1/2 MAPK module and Sam68, a protein involved in RNA processing, splicing, and v5 inclusion. Similar to HaCaT cells, highly migratory MDA-MB-231 breast cancer cells also required Sam68 expression for HGF-induced migration. However, MDA-MB-231 cell migration occurred independently of ERK1/2 and CD44v5 expression and instead required ERK5 signaling to Sam68. Phospho-mutant, but not WT-Sam68, blocked HGF-induced cell migration in both cell types; MDA-MB-435 cells behaved similarly. These results suggest that Sam68 acts as a convergence point for ERK signaling to cell migration; blockade of phospho-Sam68 may provide a new avenue for therapeutic inhibition of metastatic cancers.
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Affiliation(s)
- Alessia Locatelli
- Department of Medicine (Division of Hematology, Oncology, and Transplantation), Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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24
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Iwai LK, Benoist C, Mathis D, White FM. Quantitative phosphoproteomic analysis of T cell receptor signaling in diabetes prone and resistant mice. J Proteome Res 2010; 9:3135-45. [PMID: 20438120 DOI: 10.1021/pr100035b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes, in human patients and NOD mice, results from an immune attack on insulin-producing beta-cells of the pancreas by autoreactive T lymphocytes. In NOD mice, genetically controlled perturbations in the signaling pathways downstream of the antigen-specific T cell receptor (TCR) may be instrumental in the altered responses of T cells, manifest as inefficient induction of apoptosis after recognition of self-antigens in the thymus or as perturbed reactivity of mature T cells in peripheral organs. To map this signaling difference(s), we have used mass spectrometry-based quantitative phosphoproteomics to compare the activation of primary CD4(+) T cells of diabetes-prone NOD and -resistant B6.H2g7 mice. Immunoprecipitation and IMAC purification of tyrosine-phosphorylated peptides, combined with a stable-isotope iTRAQ labeling, enabled us to identify and quantify over 77 phosphorylation events in 54 different proteins downstream of TCR stimulation of primary CD4(+) T cells. This analysis showed a generally higher level of phosphotyrosine in activated NOD cells, as well as several phosphorylation sites that appeared to be differentially regulated in these two strains (involving TXK, CD5, PAG1, and ZAP-70). These data highlight the differences in signaling between CD4(+) T cell compartments of NOD and B6g7 mice and may underlie the dysregulation of T cells in NOD mice.
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Affiliation(s)
- Leo K Iwai
- Department of Pathology, Harvard Medical School and Section on Immunology and Immunogenetics, Joslin Diabetes Center, Boston, Massachusetts, USA
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25
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Vartak N, Bastiaens P. Spatial cycles in G-protein crowd control. EMBO J 2010; 29:2689-99. [PMID: 20717139 PMCID: PMC2924655 DOI: 10.1038/emboj.2010.184] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 07/12/2010] [Indexed: 12/19/2022] Open
Abstract
The nature of living systems and their apparent resilience to the second law of thermodynamics has been the subject of extensive investigation and imaginative speculation. The segregation and compartmentalization of proteins is one manifestation of this departure from equilibrium conditions; the effect of which is now beginning to be elucidated. This should not come as a surprise, as even a cursory inspection of cellular processes reveals the large amount of energetic cost borne to maintain cell-scale patterns, separations and gradients of molecules. The G-proteins, kinases, calcium-responsive proteins have all been shown to contain reaction cycles that are inherently coupled to their signalling activities. G-proteins represent an important and diverse toolset used by cells to generate cellular asymmetries. Many small G-proteins in particular, are dynamically acylated to modify their membrane affinities, or localized in an activity-dependent manner, thus manipulating the mobility modes of these proteins beyond pure diffusion and leading to finely tuned steady state partitioning into cellular membranes. The rates of exchange of small G-proteins over various compartments, as well as their steady state distributions enrich and diversify the landscape of possibilities that GTPase-dependent signalling networks can display over cellular dimensions. The chemical manipulation of spatial cycles represents a new approach for the modulation of cellular signalling with potential therapeutic benefits.
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Affiliation(s)
- Nachiket Vartak
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Philippe Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
- Department of Chemistry, University of Dortmund, Dortmund, Germany
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26
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Fuller DM, Zhang W. Regulation of lymphocyte development and activation by the LAT family of adapter proteins. Immunol Rev 2010; 232:72-83. [PMID: 19909357 DOI: 10.1111/j.1600-065x.2009.00828.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Transmembrane adapter proteins (TRAPs) are critical components of signaling pathways in lymphocytes, linking antigen receptor engagement to downstream cellular processes. While these proteins lack intrinsic enzymatic activity, their phosphorylation following receptor ligation allows them to function as scaffolds for the assembly of multi-molecular signaling complexes. Many TRAPs have recently been discovered, and numerous studies demonstrate their roles in the positive and negative regulation of lymphocyte maturation, activation, and differentiation. One such example is the linker for activation of T cells (LAT) family of adapter proteins. While LAT has been shown to play an indispensable role in T-cell and mast cell function, the other family members, linker for activation of B cells (LAB) and linker for activation of X cells (LAX), are necessary to fine-tune immune responses. In addition to its well-established role in the positive regulation of lymphocyte activation, LAT exerts an inhibitory effect on T-cell receptor-mediated signaling. Furthermore, LAT, along with LAB and LAX, plays a crucial role in establishing and maintaining tolerance. Here, we review recent data concerning the regulation of lymphocyte development and activation by the LAT family of proteins.
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Affiliation(s)
- Deirdre M Fuller
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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27
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GM1-ganglioside accumulation at the mitochondria-associated ER membranes links ER stress to Ca(2+)-dependent mitochondrial apoptosis. Mol Cell 2010; 36:500-11. [PMID: 19917257 DOI: 10.1016/j.molcel.2009.10.021] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 07/29/2009] [Accepted: 10/23/2009] [Indexed: 11/23/2022]
Abstract
Mitochondria-associated ER membranes, or MAMs, define the sites of endoplasmic reticulum/mitochondria juxtaposition that control Ca(2+) flux between these organelles. We found that in a mouse model of the human lysosomal storage disease GM1-gangliosidosis, GM1-ganglioside accumulates in the glycosphingolipid-enriched microdomain (GEM) fractions of MAMs, where it interacts with the phosphorylated form of IP3 receptor-1, influencing the activity of this channel. Ca(2+) depleted from the ER is then taken up by the mitochondria, leading to Ca(2+) overload in this organelle. The latter induces mitochondrial membrane permeabilization (MMP), opening of the permeability transition pore, and activation of the mitochondrial apoptotic pathway. This study identifies the GEMs as the sites of Ca(2+) diffusion between the ER and the mitochondria. We propose a new mechanism of Ca(2+)-mediated apoptotic signaling whereby GM1 accumulation at the GEMs alters Ca(2+) dynamics and acts as a molecular effector of both ER stress-induced and mitochondria-mediated apoptosis of neuronal cells.
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28
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Börner C, Smida M, Höllt V, Schraven B, Kraus J. Cannabinoid receptor type 1- and 2-mediated increase in cyclic AMP inhibits T cell receptor-triggered signaling. J Biol Chem 2010; 284:35450-60. [PMID: 19858202 DOI: 10.1074/jbc.m109.006338] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to characterize inhibitory mechanisms on T cell receptor signaling mediated by the cannabinoid receptors CB1 and CB2. Both receptors are coupled to G(i/o) proteins, which are associated with inhibition of cyclic AMP formation. In human primary and Jurkat T lymphocytes, activation of CB1 by R(+)-methanandamide, CB2 by JWH015, and both by Delta9-tetrahydrocannabinol induced a short decrease in cyclic AMP lasting less than 1 h. However, this decrease was followed by a massive (up to 10-fold) and sustained (at least up to 48 h) increase in cyclic AMP. Mediated by the cyclic AMP-activated protein kinase A and C-terminal Src kinase, the cannabinoids induced a stable phosphorylation of the inhibitory Tyr-505 of the leukocyte-specific protein tyrosine kinase (Lck). By thus arresting Lck in its inhibited form, the cannabinoids prevented the dephosphorylation of Lck at Tyr-505 in response to T cell receptor activation, which is necessary for the subsequent initiation of T cell receptor signaling. In this way the cannabinoids inhibited the T cell receptor-triggered signaling, i.e. the activation of the zeta-chain-associated protein kinase of 70 kDa, the linker for activation of T cells, MAPK, the induction of interleukin-2, and T cell proliferation. All of the effects of the cannabinoids were blocked by the CB1 and CB2 antagonists AM281 and AM630. These findings help to better understand the immunosuppressive effects of cannabinoids and explain the beneficial effects of these drugs in the treatment of T cell-mediated autoimmune disorders like multiple sclerosis.
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Affiliation(s)
- Christine Börner
- Departments of Pharmacology and Toxicology, University of Magdeburg, 39120 Magdeburg, Germany
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29
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Src family tyrosine kinases-driven colon cancer cell invasion is induced by Csk membrane delocalization. Oncogene 2009; 29:1303-15. [PMID: 20010872 DOI: 10.1038/onc.2009.450] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The nonreceptor tyrosine kinases of the Src family (SFK) are frequently deregulated in human colorectal cancer (CRC), and they have been implicated in tumour growth and metastasis. How SFK are activated in this cancer has not been clearly established. Here, we show that the SFK-dependent invasion is induced by inactivation of the negative regulator C-terminal Src kinase, Csk. While the level of Csk was inconsistent with SFK activity in colon cancer cells, its membrane translocation, needed for efficient regulation of membrane-localized SFK activity, was impaired. Accordingly, Csk downregulation did not affect SFK oncogenic activity in these cells, whereas expression of a membrane-localized form of this kinase affected their invasive activity. Downregulation of the transmembrane and rafts-localized Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomain (PAG), was instrumental for the cytoplasmic accumulation of Csk. Re-expression of PAG in cells from late-stage CRC inhibited SFK invasive activity in a Csk-dependent manner. Conversely, inactivation of its residual expression in early-stage CRC cells promoted SFK invasive activity. Finally, this mechanism was specific to CRC as Csk coupling to SFK was readily detected in breast cancer cells. Therefore, Csk mis-localization defines a novel mechanism for SFK oncogenic activation in CRC cells.
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Baine I, Abe BT, Macian F. Regulation of T-cell tolerance by calcium/NFAT signaling. Immunol Rev 2009; 231:225-40. [PMID: 19754900 DOI: 10.1111/j.1600-065x.2009.00817.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cells that escape negative selection in the thymus must be inactivated or eliminated in the periphery through a series of mechanisms that include the induction of anergy, dominant suppression by regulatory T cells, and peripheral deletion of self-reactive T cells. Calcium signaling plays a central role in the induction of anergy in T cells, which become functionally inactivated and incapable of proliferating and expressing cytokines following antigen re-encounter. Suboptimal stimulation of T cells results in the activation of a calcium/calcineurin/nuclear factor of activated T cells-dependent cell-intrinsic program of self-inactivation. The proteins encoded by those genes are required to impose a state of functional unresponsiveness through different mechanisms that include downregulation of T-cell receptor signaling and inhibition of cytokine transcription.
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Affiliation(s)
- Ian Baine
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Henao-Mejia J, He JJ. Sam68 relocalization into stress granules in response to oxidative stress through complexing with TIA-1. Exp Cell Res 2009; 315:3381-95. [PMID: 19615357 DOI: 10.1016/j.yexcr.2009.07.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/21/2009] [Accepted: 07/08/2009] [Indexed: 12/25/2022]
Abstract
Sam68 has been implicated in a variety of important cellular processes such as RNA metabolism and intracellular signaling. We have recently shown that Sam68 cytoplasmic mutants induce stress granules (SG) and inhibit HIV-1 nef mRNA translation [J. Henao-Mejia, Y. Liu, I.W. Park, J. Zhang, J. Sanford, J.J. He, Suppression of HIV-1 Nef translation by Sam68 mutant-induced stress granules and nef mRNA sequestration, Mol. Cell 33 (2009) 87-96]. These findings prompted us to investigate the possibility and the underlying mechanisms of the wild-type counterpart Sam68 SG recruitment. Herein, we revealed that Sam68 was significantly recruited into cytoplasmic SG under oxidative stress. We then demonstrated that domain aa269-321 and KH domain were both essential for this recruitment. Nevertheless, Sam68 knockdown had no effects on SG assembly, indicating that Sam68 is not a constitutive component of the SG. Moreover, we showed that Sam68 cytoplasmic mutant-induced SG formation was independent of eIF2alpha phosphorylation. Lastly, we demonstrated that Sam68 was complexed with T-cell intracellular antigen-1 (TIA-1), a core SG component, and that the complex formation was correlated with Sam68 SG recruitment. Taken together, these results provide direct evidence for the first time that Sam68 is recruited into SG through complexing with TIA-1 in response to oxidative stress and suggest that cytoplasmic SG recruitment of Sam68 and ensuing changes in Sam68 physiological functions are part of the host response to external stressful conditions.
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Affiliation(s)
- Jorge Henao-Mejia
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Börner C, Warnick B, Smida M, Hartig R, Lindquist JA, Schraven B, Höllt V, Kraus J. Mechanisms of Opioid-Mediated Inhibition of Human T Cell Receptor Signaling. THE JOURNAL OF IMMUNOLOGY 2009; 183:882-9. [DOI: 10.4049/jimmunol.0802763] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Salmond RJ, Filby A, Qureshi I, Caserta S, Zamoyska R. T-cell receptor proximal signaling via the Src-family kinases, Lck and Fyn, influences T-cell activation, differentiation, and tolerance. Immunol Rev 2009; 228:9-22. [PMID: 19290918 DOI: 10.1111/j.1600-065x.2008.00745.x] [Citation(s) in RCA: 270] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
T-cell development in the thymus and activation of mature T cells in secondary lymphoid organs requires the ability of cells to respond appropriately to environmental signals at multiple stages of their development. The process of thymocyte selection insures a functional T-cell repertoire, while activation of naive peripheral T cells induces proliferation, gain of effector function, and, ultimately, long-lived T-cell memory. The T-cell immune response is initiated upon engagement of the T-cell receptor (TCR) and coreceptor, CD4 or CD8, by cognate antigen/major histocompatibility complexes presented by antigen-presenting cells. TCR/coreceptor engagement induces the activation of biochemical signaling pathways that, in combination with signals from costimulator molecules and cytokine receptors, direct the outcome of the response. Activation of the src-family kinases p56(lck) (Lck) and p59(fyn) (Fyn) is central to the initiation of TCR signaling pathways. This review focuses on our current understanding of the mechanisms by which these two proteins orchestrate T-cell function.
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Affiliation(s)
- Robert J Salmond
- Molecular Immunology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
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Abstract
Peripheral tolerance induction is critical for the maintenance of self-tolerance and can be mediated by immunoregulatory T cells or by direct induction of T-cell anergy or deletion. Although the molecular processes underlying anergy have been extensively studied, little is known about the molecular basis for peripheral T-cell deletion. Here, we determined the gene expression signature of peripheral CD8(+) T cells undergoing deletional tolerance, relative to those undergoing immunogenic priming or lymphopenia-induced proliferation. From these data, we report the first detailed molecular signature of cells undergoing deletion. Consistent with defective cytolysis, these cells exhibited deficiencies in granzyme up-regulation. Furthermore, they showed antigen-driven Bcl-2 down-regulation and early up-regulation of the proapoptotic protein Bim, consistent with the requirement of this BH3-only protein for peripheral T-cell deletion. Bim up-regulation was paralleled by defective interleukin-7 receptor alpha (IL-7Ralpha) chain reexpression, suggesting that Bim-dependent death may be triggered by loss of IL-7/IL-7R signaling. Finally, we observed parallels in molecular signatures between deletion and anergy, suggesting that these tolerance pathways may not be as molecularly distinct as previously surmised.
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Svojgr K, Burjanivova T, Vaskova M, Kalina T, Stary J, Trka J, Zuna J. Adaptor molecules expression in normal lymphopoiesis and in childhood leukemia. Immunol Lett 2009; 122:185-92. [DOI: 10.1016/j.imlet.2008.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 12/23/2008] [Indexed: 01/12/2023]
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An adaptor role for cytoplasmic Sam68 in modulating Src activity during cell polarization. Mol Cell Biol 2009; 29:1933-43. [PMID: 19139276 DOI: 10.1128/mcb.01707-08] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The Src-associated substrate during mitosis with a molecular mass of 68 kDa (Sam68) is predominantly nuclear and is known to associate with proteins containing the Src homology 3 (SH3) and SH2 domains. Although Sam68 is a Src substrate, little is known about the signaling pathway that link them. Src is known to be activated transiently after cell spreading, where it modulates the activity of small Rho GTPases. Herein we report that Sam68-deficient cells exhibit loss of cell polarity and cell migration. Interestingly, Sam68-deficient cells exhibited sustained Src activity after cell attachment, resulting in the constitutive tyrosine phosphorylation and activation of p190RhoGAP and its association with p120rasGAP. Consistently, we observed that Sam68-deficient cells exhibited deregulated RhoA and Rac1 activity. By using total internal reflection fluorescence microscopy, we observed Sam68 near the plasma membrane after cell attachment coinciding with phosphorylation of its C-terminal tyrosines and association with Csk. These findings show that Sam68 localizes near the plasma membrane during cell attachment and serves as an adaptor protein to modulate Src activity for proper signaling to small Rho GTPases.
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Ingley E. Csk-binding protein can regulate Lyn signals controlling cell morphology. Int J Biochem Cell Biol 2008; 41:1332-43. [PMID: 19124084 DOI: 10.1016/j.biocel.2008.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 11/26/2008] [Accepted: 12/08/2008] [Indexed: 11/25/2022]
Abstract
The Src family kinase Lyn is involved in differentiation signals emanating from activated erythropoietin (Epo) receptors, it interacts with COOH-terminal Src kinase-binding protein (Cbp), an adaptor protein that recruits negative regulators COOH-terminal Src kinase (Csk) and suppressor of cytokine signaling-1 (SOCS1). Lyn phosphorylates Cbp on several tyrosine residues, including Tyr314, which recruits Csk/SOCS1, as well as Tyr381 and Tyr409 that bind Lyns own SH2 domain. We show that Cbp alters not only the ability of erythroid cells to differentiate but also their colony morphology. Consequently, we detailed the ability of Cbp to interact with and influence Lyns ability to initiate changes in cellular architecture, which affect cell-cell and cell-substratum interactions. Over-expression of active Lyn promotes filopodia formation while inactive Lyn promotes lamellipodia formation. Conversely, Cbp over-expression, which inhibits Lyn activity, promotes lamellipodia formation, while Cbp mutants preventing its interaction/signaling consequently allow Lyn to promote filopodia formation. Thus, the Lyn-Cbp pathway and subsequent regulation of Lyn signaling and cell morphology involves a dynamic and complex series of interactions.
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Affiliation(s)
- Evan Ingley
- Cell Signalling Group, Laboratory for Cancer Medicine, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth, Australia.
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Svec A. Phosphoprotein associated with glycosphingolipid-enriched microdomains/Csk-binding protein: A protein that matters. Pathol Res Pract 2008; 204:785-92. [DOI: 10.1016/j.prp.2008.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Revised: 05/06/2008] [Accepted: 06/23/2008] [Indexed: 01/31/2023]
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Veracini L, Simon V, Richard V, Schraven B, Horejsi V, Roche S, Benistant C. The Csk-binding protein PAG regulates PDGF-induced Src mitogenic signaling via GM1. ACTA ACUST UNITED AC 2008; 182:603-14. [PMID: 18695048 PMCID: PMC2500143 DOI: 10.1083/jcb.200705102] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Spatial regulation is an important feature of signal specificity elicited by cytoplasmic tyrosine kinases of the Src family (SRC family protein tyrosine kinases [SFK]). Cholesterol-enriched membrane domains, such as caveolae, regulate association of SFK with the platelet-derived growth factor receptor (PDGFR), which is needed for kinase activation and mitogenic signaling. PAG, a ubiquitously expressed member of the transmembrane adaptor protein family, is known to negatively regulate SFK signaling though binding to Csk. We report that PAG modulates PDGFR levels in caveolae and SFK mitogenic signaling through a Csk-independent mechanism. Regulation of SFK mitogenic activity by PAG requires the first N-terminal 97 aa (PAG-N), which include the extracellular and transmembrane domains, palmitoylation sites, and a short cytoplasmic sequence. We also show that PAG-N increases ganglioside GM1 levels at the cell surface and, thus, displaces PDGFR from caveolae, a process that requires the ganglioside-specific sialidase Neu-3. In conclusion, PAG regulates PDGFR membrane partitioning and SFK mitogenic signaling by modulating GM1 levels within caveolae independently from Csk.
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Affiliation(s)
- Laurence Veracini
- Centre de Recherche en Biochimie Macromoléculare, Centre National de la Recherche Scientifique UMR5237, Universities of Montpellier I and II, 34293 Montpellier, France
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Solheim SA, Petsalaki E, Stokka AJ, Russell RB, Taskén K, Berge T. Interactions between the Fyn SH3-domain and adaptor protein Cbp/PAG derived ligands, effects on kinase activity and affinity. FEBS J 2008; 275:4863-74. [PMID: 18721137 DOI: 10.1111/j.1742-4658.2008.06626.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched domains is a transmembrane adaptor protein primarily involved in negative regulation of T-cell activation by recruitment of C-terminal Src kinase (Csk), a protein tyrosine kinase which represses Src kinase activity through C-terminal phosphorylation. Recruitment of Csk occurs via SH2-domain binding to PAG pTyr317, thus, the interaction is highly dependent on phosphorylation performed by the Src family kinase Fyn, which docks onto PAG using a dual-domain binding mode involving both SH3- and SH2-domains of Fyn. In this study, we investigated Fyn SH3-domain binding to 14-mer peptide ligands derived from Cbp/PAG-enriched microdomains sequence using biochemical, biophysical and computational techniques. Interaction kinetics and dissociation constants for the various ligands were determined by SPR. The local structural impact of ligand association has been evaluated using CD, and molecular modelling has been employed to investigate details of the interactions. We show that data from these investigations correlate with functional effects of ligand binding, assessed experimentally by kinase assays using full-length PAG proteins as substrates. The presented data demonstrate a potential method for modulation of Src family kinase tyrosine phosphorylation through minor changes of the substrate SH3-interacting motif.
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Affiliation(s)
- Silje A Solheim
- The Biotechnology Centre of Oslo, University of Oslo, Norway
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Börner C, Kraus J, Bedini A, Schraven B, Höllt V. T-cell receptor/CD28-mediated activation of human T lymphocytes induces expression of functional mu-opioid receptors. Mol Pharmacol 2008; 74:496-504. [PMID: 18463202 DOI: 10.1124/mol.108.046029] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Opiates function as immunomodulators, partly by their effects on T cells. Opioids act via mu-, delta-, and kappa-opioid receptors, among which the mu-type is of particular interest, because morphine-like opioids preferentially bind to it. Here we report that mu-opioid receptor mRNA was induced after CD3/28-mediated activation of primary human T lymphocytes and Jurkat T cells, neither of which expresses the gene constitutively. Moreover, a reporter gene construct containing 2624 base pairs of the mu-opioid receptor promoter was transactivated by CD3/28 stimulation. Transcriptional induction of the mu-opioid receptor gene was mediated by activator protein-1 (AP-1), nuclear factor-kappaB, and nuclear factor of activated T cells (NFAT). NFAT was found to bind to three sequences of the mu-opioid receptor promoter, located at nucleotides -1064, -785, and -486. Although the -486 element is in close proximity to a putative AP-1 site, there was no evidence for a combined AP-1/NFAT site. Furthermore, we demonstrated that the induction of interleukin-2 mRNA and protein in activated T cells was inhibited by morphine in cells, in which mu-opioid receptors had been induced by CD3/28 monoclonal antibodies (mAbs), and that this effect was blocked by the mu-opioid receptor-specific antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2). CD3/28 mAb-induced interleukin-2 transcription was also inhibited by the opioids fentanyl and loperamide. This indicates that the induced mu-opioid receptor mRNA is translated into functional receptor protein. Furthermore, a mu-opioid receptor-enhanced green fluorescent protein-fusion protein was localized in membranes of Jurkat cells and internalized in response to [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin but not morphine. In conclusion, these data emphasize the role of opioids in the modulation of T lymphocyte signaling.
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Affiliation(s)
- Christine Börner
- Department of Pharmacology and Toxicology, University of Magdeburg, Magdeburg, Germany
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Solheim SA, Torgersen KM, Taskén K, Berge T. Regulation of FynT Function by Dual Domain Docking on PAG/Cbp. J Biol Chem 2008; 283:2773-83. [DOI: 10.1074/jbc.m705215200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Posevitz-Fejfár A, Šmída M, Kliche S, Hartig R, Schraven B, Lindquist J. A displaced PAG enhances proximal signaling and SDF-1-induced T cell migration. Eur J Immunol 2008; 38:250-9. [DOI: 10.1002/eji.200636664] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Oncogenic association of the Cbp/PAG adaptor protein with the Lyn tyrosine kinase in human B-NHL rafts. Blood 2007; 111:2310-20. [PMID: 18070987 DOI: 10.1182/blood-2007-05-090985] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
B-non-Hodgkin lymphomas (B-NHLs) use a raft-associated signalosome made of the constitutively active Lyn kinase, the tyrosine phosphorylated Cbp/PAG adaptor, and tyrosine phosphorylated STAT3 transcription factor. No such "signalosome" is found in rafts of ALK(+) T lymphoma and Hodgkin-derived cell lines, despite similar Cbp/PAG, Lyn, and STAT3 expression and similar amounts of raft sphingolipids. Stable association of the signalosome with B-NHL rafts requires (1) a Lyn kinase (auto)phosphorylated in its regulatory and active site tyrosines, (2) a Cbp/PAG adaptor phosphorylated at tyrosine 317 and bound to Lyn SH2 via phosphotyrosine 299 and neighboring residues, and (3) a tyrosine phosphorylated STAT3 linked via SH2 to the regulatory, C-terminal tyrosine of Lyn. No Csk appears to be part of this B-NHL signalosome. An oncogenic role for Lyn was shown after exposure of B-NHL lines to Lyn inhibitors that prevented Lyn and Cbp/PAG phosphorylation, dissociated the signalosome from rafts, and eventually induced death. Cell death followed decreases in Lyn or Cbp/PAG expression levels in one mantle cell lymphoma line, but not in a Hodgkin-derived one. The Lyn-Cbp/PAG signalosome appears to control proliferation and survival in most B-NHLs and constitutes a therapeutic target in B-NHL cells that exhibit oncogenic "addiction" to the Lyn kinase.
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The sound of silence: modulating anergy in T lymphocytes. Curr Opin Immunol 2007; 19:658-64. [PMID: 17949964 DOI: 10.1016/j.coi.2007.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 08/31/2007] [Indexed: 01/22/2023]
Abstract
Understanding the intercellular and intracellular mechanisms that maintain anergy and prevent the induction of full effector function is one avenue that may allow us to manipulate immune responses. Recent studies of T cell receptor (TCR)-proximal signaling events in different models of T cell unresponsiveness have suggested that biochemically distinct forms of anergy may exist in vivo. T cell responsiveness can be altered through the control of the intracellular pool of key second messengers, such as diacylglycerol (DAG) or the lipid modification of signaling molecules, such as the Linker for activated T cells (LAT). Studies on the molecule programmed death-1 (PD-1) and its ligands have revealed that tissue-resident signals are essential in the maintenance of T cell unresponsiveness. Thus, the emerging view is that T cell anergy is a dynamic state whose establishment and maintenance can be influenced by numerous different signaling pathways.
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Inomata M, Shimada Y, Hayashi M, Shimizu J, Ohno-Iwashita Y. Impairment in a negative regulatory system for TCR signaling in CD4+T cells from old mice. FEBS Lett 2007; 581:3039-43. [PMID: 17559841 DOI: 10.1016/j.febslet.2007.05.063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 05/17/2007] [Accepted: 05/22/2007] [Indexed: 01/12/2023]
Abstract
To examine the involvement of lipid rafts in an age-associated decline in T cell function, we analyzed the effect of aging on the constituents of lipid rafts in resting mouse CD4(+) T cells. We found a pronounced, age-dependent reduction in PAG/Cbp, which is involved in the regulation of Src family kinases (SFKs) by recruiting Csk (a negative regulator of SFKs) to lipid rafts. This reduction is specific for T cells and is attributed, at least in part, to the reduction in its mRNA level. The reduction of PAG accompanies marked impairment in recruiting Csk to lipid rafts and a concomitant decrease in the inactive forms of SFKs. These findings indicate that old mouse CD4(+) T cells have a defect in a negative SFK regulatory system.
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Affiliation(s)
- Mitsushi Inomata
- Cellular Signaling Group, Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan.
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Börner C, Höllt V, Kraus J. Activation of human T cells induces upregulation of cannabinoid receptor type 1 transcription. Neuroimmunomodulation 2007; 14:281-6. [PMID: 18287809 DOI: 10.1159/000117809] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 12/14/2007] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE Effects of cannabinoids are mediated by CB1 and CB2 receptors. In addition to neuronal effects, cannabinoids are potent modulators of immune functions. In this report, we investigated whether the transcription of these receptors is regulated after activation of T lymphocytes. METHODS CB1- and CB2-specific mRNA of primary human peripheral blood T cells and cells of the human T cell line Jurkat was measured by quantitative real-time RT-PCR in response to CD3/28. Using the decoy oligonucleotide approach, transcription factors involved in the regulation were determined. A promoter analysis was performed using transient transfection of chloramphenicol acetyl transferase reporter gene constructs in Jurkat cells. RESULTS Activation of human T cells caused an induction of CB1 mRNA expression in primary human T cells (8-fold) and Jurkat cells (29-fold). In contrast, CB2 transcription was not regulated. The CD3/28-mediated upregulation of CB1 involves the transcription factors AP-1, NF kappaB and NFAT. Furthermore, 2,490 bp of the CB1 promoter mediated inducibility in response to CD3/28. CONCLUSIONS The upregulation of CB1 in activated T cells, together with the constitutive expression of CB2, enables cellular responses to cannabinoids mediated by both receptor subtypes. It may thus contribute to the understanding of the various modulatory effects of cannabinoids on activated T cells.
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Affiliation(s)
- Christine Börner
- Department of Pharmacology and Toxicology, University of Magdeburg, Magdeburg, Germany
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