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Li W, Yang Y, Zhuo F, Liu S, Zhang K, Zhang W, Huang C, Yu B. Paxbp1 is indispensable for the maintenance of peripheral CD4 T cell homeostasis. Immunology 2024; 172:641-652. [PMID: 38750609 DOI: 10.1111/imm.13802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 05/05/2024] [Indexed: 07/05/2024] Open
Abstract
The size and condition of the peripheral CD4 T cell population determine the capacity of the immune response. Under homeostatic conditions, the size of the peripheral CD4 T cell population is maintained through turnover and survival. However, the underlying mechanisms remain inadequately understood. Here, we observed a significant decrease in the percentage of CD4 T cells in the periphery following the targeted deletion of the Paxbp1 gene in mouse T cells. In the absence of Paxbp1, naïve CD4 T cells displayed reduced surface interleukin-7 receptor levels and a decreased capacity to respond to survival signals mediated by interleukin-7. In addition, naïve CD4 T cells deficient in Paxbp1 demonstrated impaired T cell antigen receptor signalling, compromised cell cycle entry, decreased proliferation, and increased apoptosis following stimulation, all of which contributed to the reduction in the number of peripheral CD4 T cells. Therefore, our study highlights the indispensable role of Paxbp1 in maintaining peripheral CD4 T cell homeostasis.
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Affiliation(s)
- Wenting Li
- Department of Dermatology, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
- Shenzhen Key Laboratory for Translational Medicine of Dermatology, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, Guangdong Province, China
| | - Yang Yang
- Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Fan Zhuo
- Department of Dermatology, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
- Shenzhen Key Laboratory for Translational Medicine of Dermatology, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, Guangdong Province, China
| | - Shenglin Liu
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, College of Biological and Food Engineering, Huaihua University, Huaihua, Hunan Province, China
| | - Kaoyuan Zhang
- Department of Dermatology, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
- Shenzhen Key Laboratory for Translational Medicine of Dermatology, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, Guangdong Province, China
| | - Wei Zhang
- Biomedical Research Institute, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen, Guangdong Province, China
| | - Cong Huang
- Department of Dermatology, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
- Shenzhen Key Laboratory for Translational Medicine of Dermatology, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, Guangdong Province, China
| | - Bo Yu
- Department of Dermatology, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
- Shenzhen Key Laboratory for Translational Medicine of Dermatology, Shenzhen Peking University - The Hong Kong University of Science and Technology Medical Center, Shenzhen, Guangdong Province, China
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Plaza-Florido A, Rodriguez-Ayllon M, Altmäe S, Ortega FB, Esteban-Cornejo I. Cardiorespiratory fitness and targeted proteomics involved in brain and cardiovascular health in children with overweight/obesity. Eur J Sport Sci 2023; 23:2076-2085. [PMID: 36622372 DOI: 10.1080/17461391.2023.2167237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cardiorespiratory fitness (CRF) is inversely associated with cardiovascular disease (CVD) risk factors and brain health impairments. However, the molecular mechanisms linking CRF to health in children are poorly understood. We aimed to examine protein levels related to brain health and CVD in plasma of fit compared to unfit children with overweight/obesity (OW/OB). Eighty-seven children with OW/OB (10.08 ± 1.1 years, 59% boys) from the ActiveBrains project were included. CRF was measured by performing a treadmill test, and children were categorized into fit or unfit. Targeted proteomics in plasma was performed using Olink's proximity extension assay technology of Neurology panel in the whole sample and of Cardiovascular panel in a subsample. Sixteen proteins (PLXNB3, sFRP3, CLEC1B, RSPO1, Gal8, CLEC10A, GCP5, MDGA1, CTSC, LAT, IL4RA, PRSS27, CXCL1, Gal9, MERTK, and GT) were differentially expressed between fit and unfit children with OW/OB after adjusting for sex, maturational status, and body mass index. However, statistically significant differences disappeared after applying FDR correction. Potential candidate proteins related to CRF levels in children with OW/OB were detected, being involved in several biological processes such as neurogenesis, immune/inflammatory response, signal transduction, platelet activation. Nevertheless, these preliminary findings should be confirmed or contrasted in future studies using larger sample sizes, longitudinal and experimental designs.HighlightsThe molecular mechanisms underlying the link of cardiorespiratory fitness (CRF) with cardiovascular and brain health in children with overweight/obesity (OW/OB) are poorly understood.Targeted proteomic analysis revealed differentially expressed proteins (PLXNB3, sFRP3, CLEC1B, RSPO1, Gal8, CLEC10A, GCP5, MDGA1, CTSC, LAT, IL4RA, PRSS27, CXCL1, Gal9, MERTK, and GT) in plasma of "Fit" compared to "Unfit" children with OW/OB. These proteins are involved in several biological processes such as immune/inflammatory response, neurogenesis, signal transduction, and cellular metabolic process.Longitudinal and experimental studies are warranted to reveal how improvements in CRF are related to changes in circulating levels of the abovementioned proteins and how they might reduce cardiovascular diseases risk factors and brain health impairments later in life.
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Affiliation(s)
- Abel Plaza-Florido
- Faculty of Sport Sciences, University of Granada, Department of Physical and Sports Education; Sport and Health University Research Institute (iMUDS), Granada, Spain
- Pediatric Exercise and Genomics Research Center, Department of Pediatrics, School of Medicine, University of California at Irvine, Irvine, USA
| | - Maria Rodriguez-Ayllon
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Signe Altmäe
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
- Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, and Division of Obstetrics and Gynecology, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Francisco B Ortega
- Faculty of Sport Sciences, University of Granada, Department of Physical and Sports Education; Sport and Health University Research Institute (iMUDS), Granada, Spain
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- CIBERobn Physiopathology of Obesity and Nutrition, Granada, Spain
| | - Irene Esteban-Cornejo
- Faculty of Sport Sciences, University of Granada, Department of Physical and Sports Education; Sport and Health University Research Institute (iMUDS), Granada, Spain
- CIBERobn Physiopathology of Obesity and Nutrition, Granada, Spain
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Bugajev V, Draberova L, Utekal P, Blazikova M, Tumova M, Draber P. Enhanced Membrane Fluidization and Cholesterol Displacement by 1-Heptanol Inhibit Mast Cell Effector Functions. Cells 2023; 12:2069. [PMID: 37626879 PMCID: PMC10453462 DOI: 10.3390/cells12162069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/27/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Signal transduction by the high-affinity IgE receptor (FcεRI) depends on membrane lipid and protein compartmentalization. Recently published data show that cells treated with 1-heptanol, a cell membrane fluidizer, exhibit changes in membrane properties. However, the functional consequences of 1-heptanol-induced changes on mast cell signaling are unknown. This study shows that short-term exposure to 1-heptanol reduces membrane thermal stability and dysregulates mast cell signaling at multiple levels. Cells treated with 1-heptanol exhibited increased lateral mobility and decreased internalization of the FcεRI. However, this did not affect the initial phosphorylation of the FcεRI-β chain and components of the SYK/LAT1/PLCγ1 signaling pathway after antigen activation. In contrast, 1-heptanol inhibited SAPK/JNK phosphorylation and effector functions such as calcium response, degranulation, and cytokine production. Membrane hyperfluidization induced a heat shock-like response via increased expression of the heat shock protein 70, increased lateral diffusion of ORAI1-mCherry, and unsatisfactory performance of STIM1-ORAI1 coupling, as determined by flow-FRET. Furthermore, 1-heptanol inhibited the antigen-induced production of reactive oxygen species and potentiated stress-induced plasma membrane permeability by interfering with heat shock protein 70 activity. The combined data suggest that 1-heptanol-mediated membrane fluidization does not interfere with the earliest biochemical steps of FcεRI signaling, such as phosphorylation of the FcεRI-β chain and components of the SYK/LAT/PLCγ1 signaling pathway, instead inhibiting the FcεRI internalization and mast cell effector functions, including degranulation and cytokine production.
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Affiliation(s)
- Viktor Bugajev
- Laboratory of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic; (L.D.); (P.U.); (M.T.)
| | - Lubica Draberova
- Laboratory of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic; (L.D.); (P.U.); (M.T.)
| | - Pavol Utekal
- Laboratory of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic; (L.D.); (P.U.); (M.T.)
| | - Michaela Blazikova
- Light Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic;
| | - Magda Tumova
- Laboratory of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic; (L.D.); (P.U.); (M.T.)
| | - Petr Draber
- Laboratory of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic; (L.D.); (P.U.); (M.T.)
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Sandouk A, Xu Z, Baruah S, Tremblay M, Hopkins JB, Chakravarthy S, Gakhar L, Schnicker NJ, Houtman JCD. GRB2 dimerization mediated by SH2 domain-swapping is critical for T cell signaling and cytokine production. Sci Rep 2023; 13:3505. [PMID: 36864087 PMCID: PMC9981690 DOI: 10.1038/s41598-023-30562-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 02/25/2023] [Indexed: 03/04/2023] Open
Abstract
GRB2 is an adaptor protein required for facilitating cytoplasmic signaling complexes from a wide array of binding partners. GRB2 has been reported to exist in either a monomeric or dimeric state in crystal and solution. GRB2 dimers are formed by the exchange of protein segments between domains, otherwise known as "domain-swapping". Swapping has been described between SH2 and C-terminal SH3 domains in the full-length structure of GRB2 (SH2/C-SH3 domain-swapped dimer), as well as between α-helixes in isolated GRB2 SH2 domains (SH2/SH2 domain-swapped dimer). Interestingly, SH2/SH2 domain-swapping has not been observed within the full-length protein, nor have the functional influences of this novel oligomeric conformation been explored. We herein generated a model of full-length GRB2 dimer with an SH2/SH2 domain-swapped conformation supported by in-line SEC-MALS-SAXS analyses. This conformation is consistent with the previously reported truncated GRB2 SH2/SH2 domain-swapped dimer but different from the previously reported, full-length SH2/C-terminal SH3 (C-SH3) domain-swapped dimer. Our model is also validated by several novel full-length GRB2 mutants that favor either a monomeric or a dimeric state through mutations within the SH2 domain that abrogate or promote SH2/SH2 domain-swapping. GRB2 knockdown and re-expression of selected monomeric and dimeric mutants in a T cell lymphoma cell line led to notable defects in clustering of the adaptor protein LAT and IL-2 release in response to TCR stimulation. These results mirrored similarly-impaired IL-2 release in GRB2-deficient cells. These studies show that a novel dimeric GRB2 conformation with domain-swapping between SH2 domains and monomer/dimer transitions are critical for GRB2 to facilitate early signaling complexes in human T cells.
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Affiliation(s)
- Aline Sandouk
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, 52242, USA
| | - Zhen Xu
- Protein and Crystallography Facility, University of Iowa, Iowa City, IA, 52242, USA
| | - Sankar Baruah
- Protein and Crystallography Facility, University of Iowa, Iowa City, IA, 52242, USA
| | - Mikaela Tremblay
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, 52242, USA
| | - Jesse B Hopkins
- Biophysics Collaborative Access Team, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Srinivas Chakravarthy
- Biophysics Collaborative Access Team, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Lokesh Gakhar
- Protein and Crystallography Facility, University of Iowa, Iowa City, IA, 52242, USA
- Department of Biochemistry and Molecular Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Nicholas J Schnicker
- Protein and Crystallography Facility, University of Iowa, Iowa City, IA, 52242, USA
| | - Jon C D Houtman
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, 52242, USA.
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, 52242, USA.
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5
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Li J, Zhang M, Ma W, Yang B, Lu H, Zhou F, Zhang L. Post-translational modifications in liquid-liquid phase separation: a comprehensive review. MOLECULAR BIOMEDICINE 2022; 3:13. [PMID: 35543798 PMCID: PMC9092326 DOI: 10.1186/s43556-022-00075-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/25/2022] [Indexed: 11/23/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) has received significant attention in recent biological studies. It refers to a phenomenon that biomolecule exceeds the solubility, condensates and separates itself from solution in liquid like droplets formation. Our understanding of it has also changed from memebraneless organelles to compartmentalization, muti-functional crucibles, and reaction regulators. Although this phenomenon has been employed for a variety of biological processes, recent studies mainly focus on its physiological significance, and the comprehensive research of the underlying physical mechanism is limited. The characteristics of side chains of amino acids and the interaction tendency of proteins function importantly in regulating LLPS thus should be pay more attention on. In addition, the importance of post-translational modifications (PTMs) has been underestimated, despite their abundance and crucial functions in maintaining the electrostatic balance. In this review, we first introduce the driving forces and protein secondary structures involved in LLPS and their different physical functions in cell life processes. Subsequently, we summarize the existing reports on PTM regulation related to LLPS and analyze the underlying basic principles, hoping to find some common relations between LLPS and PTM. Finally, we speculate several unreported PTMs that may have a significant impact on phase separation basing on the findings.
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Affiliation(s)
- Jingxian Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Mengdi Zhang
- School of Medicine, Zhejiang University City College, Hangzhou, 310015, Zhejiang, China
| | - Weirui Ma
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Bing Yang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Huasong Lu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Fangfang Zhou
- Institutes of Biology and Medical Science, Soochow University, Suzhou, 215123, P. R. China.
| | - Long Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China.
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6
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Ni G, Liu X, Li H, Fogarty CE, Chen S, Zhang P, Liu Y, Wu X, Wei MQ, Chen G, Zhang P, Wang T. Topical Application of Temperature-Sensitive Gel Containing Caerin 1.1 and 1.9 Peptides on TC-1 Tumour-Bearing Mice Induced High-Level Immune Response in the Tumour Microenvironment. Front Oncol 2021; 11:754770. [PMID: 34858827 PMCID: PMC8632150 DOI: 10.3389/fonc.2021.754770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 10/11/2021] [Indexed: 01/22/2023] Open
Abstract
The development of topical cream drugs that increase the immune activation of tumour-infiltrating lymphocytes against tumour and chronic viral infection-associated lesions is of great immunotherapeutic significance. This study demonstrates that the topical application of a temperature-sensitive gel containing caerin 1.1 and 1.9 peptides reduces nearly 50% of the tumour weight of HPV16 E6/E7-transformed TC-1 tumour-bearing mice via improving the tumour microenvironment. Confocal microscopy confirms the time-dependent penetration of caerin 1.9 through the epidermal layer of the ear skin structure of mice. Single-cell transcriptomic analysis shows that the caerin 1.1/1.9 gel expands the populations with high immune activation level and largely stimulates the pro-inflammatory activity of NK and dendritic cells. Closely associated with INFα response, Cebpb seems to play a key role in altering the function of all Arg1hi macrophages in the caerin group. In addition, the caerin gel treatment recruits almost two-fold more activated CD8+ T cells to the TME, relative to the untreated tumour, which shows a synergistic effect derived from the regulation of S1pr1, Ccr7, Ms4a4b and Gimap family expression. The TMT10plex-labelling proteomic quantification further demonstrates the activation of interferon-alpha/beta secretion and response to cytokine stimulus by the caerin gel, while the protein contents of several key regulators were elevated by more than 30%, such as Cd5l, Gzma, Ifit1, Irf9 and Stat1. Computational integration of the proteome with the single-cell transcriptome consistently suggested greater activation of NK and T cells with the topical application of caerin peptide gel.
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Affiliation(s)
- Guoying Ni
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China.,Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD, Australia.,Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia.,The First Affiliated Hospital/School of Clinical Medicine of Guangdong Pharmaceutical University , Guangzhou, China
| | - Xiaosong Liu
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China.,Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
| | - Hejie Li
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD, Australia.,School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
| | - Conor E Fogarty
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD, Australia.,School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
| | - Shu Chen
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China
| | - Pingping Zhang
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China
| | - Ying Liu
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China
| | - Xiaolian Wu
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China
| | - Ming Q Wei
- Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Guoqiang Chen
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, China
| | - Ping Zhang
- Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Tianfang Wang
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD, Australia.,School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
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7
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Arkee T, Hostager BS, Houtman JCD, Bishop GA. TRAF3 in T Cells Restrains Negative Regulators of LAT to Promote TCR/CD28 Signaling. THE JOURNAL OF IMMUNOLOGY 2021; 207:322-332. [PMID: 34145060 DOI: 10.4049/jimmunol.2001220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/29/2021] [Indexed: 12/11/2022]
Abstract
The adaptor protein TNFR-associated factor 3 (TRAF3) is required for in vivo T cell effector functions and for normal TCR/CD28 signaling. TRAF3-mediated enhancement of TCR function requires engagement of both CD3 and CD28, but the molecular mechanisms underlying how TRAF3 interacts with and impacts TCR/CD28-mediated complexes to enhance their signaling remains an important knowledge gap. We investigated how TRAF3 is recruited to, and regulates, CD28 as a TCR costimulator. Direct association with known signaling motifs in CD28 was dispensable for TRAF3 recruitment; rather, TRAF3 associated with the CD28-interacting protein linker of activated T cells (LAT) in human and mouse T cells. TRAF3-LAT association required the TRAF3 TRAF-C domain and a newly identified TRAF2/3 binding motif in LAT. TRAF3 inhibited function of the LAT-associated negative regulatory protein Dok1, which is phosphorylated at an inhibitory tyrosine residue by the tyrosine kinase breast tumor kinase (Brk/PTK6). TRAF3 regulated Brk activation in T cells, limiting the association of protein tyrosine phosphatase 1B (PTP1B) with the LAT complex. In TRAF3-deficient cells, LAT complex-associated PTP1B was associated with dephosphorylation of Brk at an activating tyrosine residue, potentially reducing its ability to inhibit Dok1. Consistent with these findings, inhibiting PTP1B activity in TRAF3-deficient T cells rescued basal and TCR/CD28-mediated activation of Src family kinases. These results reveal a new mechanism for promotion of TCR/CD28-mediated signaling through restraint of negative regulation of LAT by TRAF3, enhancing the understanding of regulation of the TCR complex.
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Affiliation(s)
- Tina Arkee
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA.,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA
| | - Bruce S Hostager
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA
| | - Jon C D Houtman
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA.,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA
| | - Gail A Bishop
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA; .,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA.,Department of Internal Medicine, The University of Iowa, Iowa City, IA; and.,Iowa City VA Medical Center, Iowa City, IA
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8
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Tremblay MM, Ollinger T, Houtman JCD. The membrane proximal proline-rich region and correct order of C-terminal tyrosines on the adaptor protein LAT are required for TCR-mediated signaling and downstream functions. Cell Signal 2020; 76:109790. [PMID: 32979494 DOI: 10.1016/j.cellsig.2020.109790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022]
Abstract
The primary activating receptor for T cells is the T cell receptor (TCR), which is stimulated upon binding to an antigen/MHC complex. TCR activation results in the induction of regulated signaling pathways vital for T cell differentiation, cellular adhesion and cytokine release. A critical TCR-induced signaling protein is the adaptor protein LAT. Upon TCR stimulation, LAT is phosphorylated on conserved tyrosines, which facilitates the formation of multiprotein complexes needed for propagation of signaling pathways. Although the role of the conserved tyrosines in LAT-mediated signaling has been investigated, few studies have examined the role of larger regions of LAT in TCR-induced pathways. In this study, a sequence alignment of 97 mammalian LAT proteins was used to identify several "functional" domains on LAT. Using LAT mutants expressed in Jurkat E6.1 cells, we observed that the membrane proximal, proline-rich region of LAT and the correct order of domains containing conserved tyrosines are necessary for optimal TCR-mediated early signaling, cytokine production, and cellular adhesion. Together, these data show that LAT contains distinct regions whose presence and correct order are required for the propagation of TCR-mediated signaling pathways.
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Affiliation(s)
- Mikaela M Tremblay
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, USA
| | - Tomye Ollinger
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, USA
| | - Jon C D Houtman
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, USA.
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9
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Zhu JJ, Stenfeldt C, Bishop EA, Canter JA, Eschbaumer M, Rodriguez LL, Arzt J. Mechanisms of Maintenance of Foot-and-Mouth Disease Virus Persistence Inferred From Genes Differentially Expressed in Nasopharyngeal Epithelia of Virus Carriers and Non-carriers. Front Vet Sci 2020; 7:340. [PMID: 32637426 PMCID: PMC7318773 DOI: 10.3389/fvets.2020.00340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) causes persistent infection of nasopharyngeal epithelial cells in ~50% of infected ruminants. The mechanisms involved are not clear. This study provides a continued investigation of differentially expressed genes (DEG) identified in a previously published transcriptomic study analyzing micro-dissected epithelial samples from FMDV carriers and non-carriers. Pathway analysis of DEG indicated that immune cell trafficking, cell death and hematological system could be affected by the differential gene expression. Further examination of the DEG identified five downregulated (chemerin, CCL23, CXCL15, CXCL16, and CXCL17) and one upregulated (CCL2) chemokines in carriers compared to non-carriers. The differential expression could reduce the recruitment of neutrophils, antigen-experienced T cells and dendritic cells and increase the migration of macrophages and NK cells to the epithelia in carriers, which was supported by DEG expressed in these immune cells. Downregulated chemokine expression could be mainly due to the inhibition of canonical NFκB signaling based on DEG in the signaling pathways and transcription factor binding sites predicted from the proximal promoters. Additionally, upregulated CD69, IL33, and NID1 and downregulated CASP3, IL17RA, NCR3LG1, TP53BP1, TRAF3, and TRAF6 in carriers could inhibit the Th17 response, NK cell cytotoxicity and apoptosis. Based on our findings, we hypothesize that (1) under-expression of chemokines that recruit neutrophils, antigen-experienced T cells and dendritic cells, (2) blocking NK cell binding to target cells and (3) suppression of apoptosis induced by death receptor signaling, viral RNA, and cell-mediated cytotoxicity in the epithelia compromised virus clearance and allowed FMDV to persist. These hypothesized mechanisms provide novel information for further investigation of persistent FMDV infection.
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Affiliation(s)
- James J Zhu
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Carolina Stenfeldt
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States.,Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Elizabeth A Bishop
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Jessica A Canter
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States.,Plum Island Animal Disease Center, Oak Ridge Institute for Science and Education (ORISE), Orient, NY, United States
| | - Michael Eschbaumer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Luis L Rodriguez
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Jonathan Arzt
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
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10
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Lo WL, Shah NH, Rubin SA, Zhang W, Horkova V, Fallahee IR, Stepanek O, Zon LI, Kuriyan J, Weiss A. Slow phosphorylation of a tyrosine residue in LAT optimizes T cell ligand discrimination. Nat Immunol 2019; 20:1481-1493. [PMID: 31611699 PMCID: PMC6858552 DOI: 10.1038/s41590-019-0502-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/20/2019] [Indexed: 02/07/2023]
Abstract
Self-non-self discrimination is central to T cell-mediated immunity. The kinetic proofreading model can explain T cell antigen receptor (TCR) ligand discrimination; however, the rate-limiting steps have not been identified. Here, we show that tyrosine phosphorylation of the T cell adapter protein LAT at position Y132 is a critical kinetic bottleneck for ligand discrimination. LAT phosphorylation at Y132, mediated by the kinase ZAP-70, leads to the recruitment and activation of phospholipase C-γ1 (PLC-γ1), an important effector molecule for T cell activation. The slow phosphorylation of Y132, relative to other phosphosites on LAT, is governed by a preceding glycine residue (G131) but can be accelerated by substituting this glycine with aspartate or glutamate. Acceleration of Y132 phosphorylation increases the speed and magnitude of PLC-γ1 activation and enhances T cell sensitivity to weaker stimuli, including weak agonists and self-peptides. These observations suggest that the slow phosphorylation of Y132 acts as a proofreading step to facilitate T cell ligand discrimination.
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Affiliation(s)
- Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Neel H Shah
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Department of Chemistry, Columbia University, New York, NY, USA
| | - Sara A Rubin
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute; Program in Immunology, Harvard Medical School, Boston, MA, USA
| | - Weiguo Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC, USA
| | - Veronika Horkova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ian R Fallahee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ondrej Stepanek
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Leonard I Zon
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute; Program in Immunology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston Children's Hospital and Harvard University, Boston, MA, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, USA.
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11
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Shifrut E, Carnevale J, Tobin V, Roth TL, Woo JM, Bui CT, Li PJ, Diolaiti ME, Ashworth A, Marson A. Genome-wide CRISPR Screens in Primary Human T Cells Reveal Key Regulators of Immune Function. Cell 2018; 175:1958-1971.e15. [PMID: 30449619 DOI: 10.1016/j.cell.2018.10.024] [Citation(s) in RCA: 324] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/08/2018] [Accepted: 10/08/2018] [Indexed: 12/11/2022]
Abstract
Human T cells are central effectors of immunity and cancer immunotherapy. CRISPR-based functional studies in T cells could prioritize novel targets for drug development and improve the design of genetically reprogrammed cell-based therapies. However, large-scale CRISPR screens have been challenging in primary human cells. We developed a new method, single guide RNA (sgRNA) lentiviral infection with Cas9 protein electroporation (SLICE), to identify regulators of stimulation responses in primary human T cells. Genome-wide loss-of-function screens identified essential T cell receptor signaling components and genes that negatively tune proliferation following stimulation. Targeted ablation of individual candidate genes characterized hits and identified perturbations that enhanced cancer cell killing. SLICE coupled with single-cell RNA sequencing (RNA-seq) revealed signature stimulation-response gene programs altered by key genetic perturbations. SLICE genome-wide screening was also adaptable to identify mediators of immunosuppression, revealing genes controlling responses to adenosine signaling. The SLICE platform enables unbiased discovery and characterization of functional gene targets in primary cells.
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Affiliation(s)
- Eric Shifrut
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Julia Carnevale
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Victoria Tobin
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Theodore L Roth
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jonathan M Woo
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christina T Bui
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - P Jonathan Li
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Morgan E Diolaiti
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alan Ashworth
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alexander Marson
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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12
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Wang LN, Gao MH, Wang B, Cong BB, Zhang SC. A role for GPI-CD59 in promoting T-cell signal transduction via LAT. Oncol Lett 2018. [PMID: 29541246 PMCID: PMC5835848 DOI: 10.3892/ol.2018.7908] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Cluster of differentiation 59 (CD59) is a glycosylphosphatidylinositol-anchored protein. Cross-linking of CD59 with specific monoclonal antibodies can cause a series of intracellular signal transduction events. However, the underlying molecular mechanisms are poorly understood. Linker for activation of T-cells (LAT) is a crucial adaptor protein in T-cell signaling, and its phosphorylation and palmitoylation are essential for its localization and function. In a previous study by the present authors, it was demonstrated that CD59 may be responsible for LAT palmitoylation, thereby regulating T-cell signal transduction. The present study detected the co-localization of LAT and CD59 in lipid rafts by transfecting Jurkat cells with lentivirus vectors carrying the LAT-enhanced green fluorescent protein fusion protein. In addition, LAT and CD59 were shown to have a synergistic effect on the proliferation of Jurkat cells. The results also indicated that CD59 may transfer the palmitate group from phosphatidylinositol to LAT to form LAT palmitate, which then localizes to lipid rafts to regulate T-cell activation. The results of the present study provided novel insights into the role of CD59 in T-cell signal transduction.
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Affiliation(s)
- Li-Na Wang
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China.,Department of Blood Transfusion, Qilu Hospital of Shandong University (Qingdao), Qingdao, Shandong 266071, P.R. China
| | - Mei-Hua Gao
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Bing Wang
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Bei-Bei Cong
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Shu-Chao Zhang
- Department of Transfusion, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
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13
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SCIMP is a transmembrane non-TIR TLR adaptor that promotes proinflammatory cytokine production from macrophages. Nat Commun 2017; 8:14133. [PMID: 28098138 PMCID: PMC5253658 DOI: 10.1038/ncomms14133] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/02/2016] [Indexed: 01/04/2023] Open
Abstract
Danger signals activate Toll-like receptors (TLRs), thereby initiating inflammatory responses. Canonical TLR signalling, via Toll/Interleukin-1 receptor domain (TIR)-containing adaptors and proinflammatory transcription factors such as NF-κB, occurs in many cell types; however, additional mechanisms are required for specificity of inflammatory responses in innate immune cells. Here we show that SCIMP, an immune-restricted, transmembrane adaptor protein (TRAP), promotes selective proinflammatory cytokine responses by direct modulation of TLR4. SCIMP is a non-TIR-containing adaptor, binding directly to the TLR4-TIR domain in response to lipopolysaccharide. In macrophages, SCIMP is constitutively associated with the Lyn tyrosine kinase, is required for tyrosine phosphorylation of TLR4, and facilitates TLR-inducible production of the proinflammatory cytokines IL-6 and IL-12p40. Point mutations in SCIMP abrogating TLR4 binding also prevent SCIMP-mediated cytokine production. SCIMP is, therefore, an immune-specific TLR adaptor that shapes host defence and inflammation. Toll-like receptors engage TIR domain-containing adaptors to control proinflammatory gene expression in response to pathogens and tissue damage. Here the authors show that the non-TIR domain-containing transmembrane protein SCIMP is a previously unrecognized TLR adaptor expressed by macrophages.
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14
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LAT alleviates Th2/Treg imbalance in an OVA-induced allergic asthma mouse model through LAT-PLC-γ1 interaction. Int Immunopharmacol 2017; 44:9-15. [PMID: 28063403 DOI: 10.1016/j.intimp.2016.12.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Low expression of linker for activation of T cells (LAT) is observed in asthma. LAT and its downstream regulator, phospholipase C-gamma 1 (PLC-γ1) play important roles in the T cell antigen receptor signaling pathway, and their interaction is associated with CD4+ cell polarization. Here, we investigated whether LAT can alleviate the imbalance among CD4+ cell subgroups and the possible mechanism. METHODS An ovalbumin-induced allergic asthma mouse model was established and LAT plasmid was delivered. The pathological changes in lung were evaluated by hematoxylin and eosin and periodic acid-Schiff staining. The typical cytokines released by T helper 2 (Th2) and regulatory T (Treg) cells were measured using enzyme-linked immunosorbent assay and the number of Th1, Th2, and Treg cells were determined using flow cytometry. Lung CD4+ T cells were isolated by magnetic isolation. The mRNA expression of LAT and PLC-γ1 was determined by real-time PCR. Co-Immunoprecipitation was performed to confirm the interaction between LAT and PLC-γ1. The protein expression of LAT, PLC-γ1 and corresponding downstream signaling factors were determined by western blotting. RESULTS The delivery of LAT DNA to the lung could suppress an overactive Th2 response by decreasing allergic response and Th2 cytokine secretion, and by increasing Treg cytokine secretion. The Th2/Treg imbalance in lung and decreased phosphorylated PLC-γ1 expression in lung CD4+ T cells were rectified by LAT DNA delivery. Excessive activation of the Raf-MEK-ERK and PI3K-AKT-CREB pathways after asthma is attenuated by LAT. CONCLUSION The site-specific delivery of LAT DNA to the lung could suppress an overactive Th2 response and rectify the Th2/Treg imbalance in asthmatic mouse model. LAT-PLC-γ1 interaction may contribute to LAT activity in vivo and LAT protects against asthma partly via Raf-MEK-ERK and PI3K-AKT-CREB pathways. The delivery of LAT DNA could offer a novel and safe strategy for asthma prevention.
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15
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Bacchelli C, Moretti FA, Carmo M, Adams S, Stanescu HC, Pearce K, Madkaikar M, Gilmour KC, Nicholas AK, Woods CG, Kleta R, Beales PL, Qasim W, Gaspar HB. Mutations in linker for activation of T cells (LAT) lead to a novel form of severe combined immunodeficiency. J Allergy Clin Immunol 2016; 139:634-642.e5. [PMID: 27522155 DOI: 10.1016/j.jaci.2016.05.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/17/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Signaling through the T-cell receptor (TCR) is critical for T-cell development and function. Linker for activation of T cells (LAT) is a transmembrane adaptor signaling molecule that is part of the TCR complex and essential for T-cell development, as demonstrated by LAT-deficient mice, which show a complete lack of peripheral T cells. OBJECTIVE We describe a pedigree affected by a severe combined immunodeficiency phenotype with absent T cells and normal B-cell and natural killer cell numbers. A novel homozygous frameshift mutation in the gene encoding for LAT was identified in this kindred. METHODS Genetic, molecular, and functional analyses were used to identify and characterize the LAT defect. Clinical and immunologic analysis of patients was also performed and reported. RESULTS Homozygosity mapping was used to identify potential defective genes. Sanger sequencing of the LAT gene showed a mutation that resulted in a premature stop codon and protein truncation leading to complete loss of function and loss of expression of LAT in the affected family members. We also demonstrate loss of LAT expression and lack of TCR signaling restoration in LAT-deficient cell lines reconstituted with a synthetic LAT gene bearing this severe combined immunodeficiency mutation. CONCLUSION For the first time, the results of this study show that inherited LAT deficiency should be considered in patients with combined immunodeficiency with T-cell abnormalities.
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Affiliation(s)
- Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Federico A Moretti
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Marlene Carmo
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Stuart Adams
- Bone Marrow Transplantation, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Horia C Stanescu
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Kerra Pearce
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Manisha Madkaikar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Pediatric Immunology and Leukocyte Biology, National Institute of Immunohematology, ICMR, Mumbai, India
| | - Kimberly C Gilmour
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Adeline K Nicholas
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - C Geoffrey Woods
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Robert Kleta
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Phil L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Waseem Qasim
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - H Bobby Gaspar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom.
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16
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Ehling P, Meuth P, Eichinger P, Herrmann AM, Bittner S, Pawlowski M, Pankratz S, Herty M, Budde T, Meuth SG. Human T cells in silico: Modelling their electrophysiological behaviour in health and disease. J Theor Biol 2016; 404:236-250. [PMID: 27288542 DOI: 10.1016/j.jtbi.2016.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/27/2016] [Accepted: 06/01/2016] [Indexed: 01/27/2023]
Abstract
Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simulating the electrophysiological behaviour of resting and activated human CD4(+) T cells under basal conditions and during extracellular acidification. The latter allows for the very first time to assess the electrophysiological consequences of tissue acidosis accompanying most forms of inflammation.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany.
| | - Patrick Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Paul Eichinger
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München TUM, Ismaninger Strasse 22, 81675 Munich, Germany
| | - Alexander M Herrmann
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Matthias Pawlowski
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany; Wellcome Trust and MRC Cambridge Stem Cell Institute, and Anne McLaren Laboratory for Regenerative Medicine, University of Cambridge, West Forvie Building, Forvie Site, Robinson Way, Cambridge, UK
| | - Susann Pankratz
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
| | - Michael Herty
- RWTH Aachen University, Mathematics (Continuous optimization), Templergraben 55, 52056 Aachen, Germany
| | - Thomas Budde
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Münster, Germany
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17
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Yan W, Wang L, Jiang J, Xu W, Gong Z, Duan Q, Li C, Song H, Che L, Shen Y, Zhou L. Differential expression of T cell-related genes in AMI and SA stages of coronary artery disease. Int J Clin Exp Med 2015; 8:10875-84. [PMID: 26379881 PMCID: PMC4565264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 06/26/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To identify differentially expressed T cells-related genes in peripheral blood mononuclear cells and compare their differences in T cell activation and subset functions in different stages of coronary atherosclerosis disease (CAD). METHODS 20 patients with acute myocardial infarction patients (AMI), 20 patients with stable angina pectoris (SA) and 20 healthy volunteers were recruited into the study. Whole human genome microarray analysis was used to detect the expression of T cell related genes among three groups. RESULTS mRNA expression of 68 genes involved in T cell was detected. 1) Antigen recognition: in the AMI patients 12 genes were down-regulated and 9 were significantly down-regulated among all 13 genes, compared with those of the SA and the control group, respectively. 2) Co-stimulators and regulators of T cell activation: among 16 genes in the AMI patients, 15 genes were lower and 8 were significantly lower than the other two groups. 3) T cell subsets, CTL: all 11 genes in the AMI patients were down-regulated, particularly GZMM and CASP8 were significantly down-regulated compared with the SA patients and controls. Th1/Th2: in the AMI patients, gene expressions including IL1 and IL18 were significantly higher, whereas GATA3 mRNA was significantly lower than those in other two groups. Th17/Treg: in the AMI group, RORC and CCR6 mRNAs were significantly down-regulated compared with the control group, while CD25 and CD127 expressions were significantly lower than SA group. There was no difference in T cell related genes between the SA patients and the controls. CONCLUSIONS In the AMI patients, the mRNA expression of T cell antigen recognition, activation and subset functions was imbalanced or decreased, indicating the dysfunction of cellular immunity in patients with AMI. Then improving T cell mediated cellular immunity may be considered as a potential target for medical interventions in the patients with AMI.
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Affiliation(s)
- Wenwen Yan
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Lemin Wang
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Jinfa Jiang
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Wenjun Xu
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Zhu Gong
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Qianglin Duan
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Chuanrong Li
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Haoming Song
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Lin Che
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Yuqin Shen
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
| | - Lin Zhou
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China
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18
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Regions outside of conserved PxxPxR motifs drive the high affinity interaction of GRB2 with SH3 domain ligands. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2560-9. [PMID: 26079855 DOI: 10.1016/j.bbamcr.2015.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/26/2015] [Accepted: 06/10/2015] [Indexed: 12/20/2022]
Abstract
SH3 domains are evolutionarily conserved protein interaction domains that control nearly all cellular processes in eukaryotes. The current model is that most SH3 domains bind discreet PxxPxR motifs with weak affinity and relatively low selectivity. However, the interactions of full-length SH3 domain-containing proteins with ligands are highly specific and have much stronger affinity. This suggests that regions outside of PxxPxR motifs drive these interactions. In this study, we observed that PxxPxR motifs were required for the binding of the adaptor protein GRB2 to short peptides from its ligand SOS1. Surprisingly, PxxPxR motifs from the proline rich region of SOS1 or CBL were neither necessary nor sufficient for the in vitro or in vivo interaction with full-length GRB2. Together, our findings show that regions outside of the consensus PxxPxR sites drive the high affinity association of GRB2 with SH3 domain ligands, suggesting that the binding mechanism for this and other SH3 domain interactions may be more complex than originally thought.
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19
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Cadra S, Gucciardi A, Valignat MP, Theodoly O, Vacaflores A, Houtman JC, Lellouch AC. ROZA-XL, an improved FRET based biosensor with an increased dynamic range for visualizing Zeta Associated Protein 70 kD (ZAP-70) tyrosine kinase activity in live T cells. Biochem Biophys Res Commun 2015; 459:405-10. [DOI: 10.1016/j.bbrc.2015.02.117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 02/21/2015] [Indexed: 11/24/2022]
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20
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Bilal MY, Houtman JCD. GRB2 Nucleates T Cell Receptor-Mediated LAT Clusters That Control PLC-γ1 Activation and Cytokine Production. Front Immunol 2015; 6:141. [PMID: 25870599 PMCID: PMC4378308 DOI: 10.3389/fimmu.2015.00141] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/14/2015] [Indexed: 12/16/2022] Open
Abstract
GRB2 is a ubiquitously expressed adaptor protein required for signaling downstream of multiple receptors. To address the role of GRB2 in receptor-mediated signaling, the expression of GRB2 was suppressed in human CD4+ T cells and its role downstream of the T cell receptor (TCR) was examined. Interestingly, GRB2 deficient T cells had enhanced signaling from complexes containing the TCR. However, GRB2 deficient T cells had substantially reduced production of IL-2 and IFN-γ. This defect was attributed to diminished formation of linker for activation of T cells (LAT) signaling clusters, which resulted in reduced MAP kinase activation, calcium flux, and PLC-γ1 recruitment to LAT signaling clusters. Add back of wild-type GRB2, but not a novel N-terminal SH3 domain mutant, rescued LAT microcluster formation, calcium mobilization, and cytokine release, providing the first direct evidence that GRB2, and its ability to bind to SH3 domain ligands, is required for establishing LAT microclusters. Our data demonstrate that the ability of GRB2 to facilitate protein clusters is equally important in regulating TCR-mediated functions as its capacity to recruit effector proteins. This highlights that GRB2 regulates signaling downstream of adaptors and receptors by both recruiting effector proteins and regulating the formation of signaling complexes.
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Affiliation(s)
- Mahmood Yousif Bilal
- Interdisciplinary Graduate Program in Immunology, University of Iowa , Iowa City, IA , USA
| | - Jon C D Houtman
- Interdisciplinary Graduate Program in Immunology, University of Iowa , Iowa City, IA , USA ; Department of Microbiology, Carver College of Medicine, University of Iowa , Iowa City, IA , USA
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21
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Chapman NM, Houtman JCD. Functions of the FAK family kinases in T cells: beyond actin cytoskeletal rearrangement. Immunol Res 2015; 59:23-34. [PMID: 24816556 DOI: 10.1007/s12026-014-8527-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
T cells control the focus and extent of adaptive immunity in infectious and pathological diseases. The activation of T cells occurs when the T cell antigen receptor (TCR) and costimulatory and/or adhesion receptors are engaged by their ligands. This process drives signaling that promotes cytoskeletal rearrangement and transcription factor activation, both of which regulate the quality and magnitude of the T cell response. However, it is not fully understood how different receptor-induced signals combine to alter T cell activation. The related non-receptor tyrosine kinases focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2) are phosphorylated downstream of the TCR and several costimulatory and adhesion receptors. FAK family proteins integrate receptor-mediated signals that influence actin cytoskeletal rearrangement and effector T cell responses. In this review, we summarize the receptor-specific roles that FAK and Pyk2 control to influence T cell development and activation.
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Affiliation(s)
- Nicole M Chapman
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, 52242, USA
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Witsenburg JJ, Sinzinger MD, Stoevesandt O, Ruttekolk IR, Roth G, Adjobo-Hermans MJW, Brock R. A peptide-functionalized polymer as a minimal scaffold protein to enhance cluster formation in early T cell signal transduction. Chembiochem 2015; 16:602-10. [PMID: 25663649 DOI: 10.1002/cbic.201402622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Indexed: 12/28/2022]
Abstract
In cellular signal transduction, scaffold proteins provide binding sites to organize signaling proteins into supramolecular complexes and act as nodes in the signaling network. Furthermore, multivalent interactions between the scaffold and other signaling proteins contribute to the formation of protein microclusters. Such microclusters are prominent in early T cell signaling. Here, we explored the minimal structural requirement for a scaffold protein by coupling multiple copies of a proline-rich peptide corresponding to an interaction motif for the SH3 domain of the adaptor protein GADS to an N-(2-hydroxypropyl)methacrylamide polymer backbone. When added to GADS-containing cell lysates, these scaffolds (but not individual peptides) promoted the binding of GADS to peptide microarrays. This can be explained by the cross-linking of GADS into larger complexes. Furthermore, following import into Jurkat T cell leukemia cells, this synthetic scaffold enhanced the formation of microclusters of signaling proteins.
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Affiliation(s)
- J Joris Witsenburg
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen (The Netherlands)
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23
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Ehling P, Cerina M, Budde T, Meuth SG, Bittner S. The CNS under pathophysiologic attack--examining the role of K₂p channels. Pflugers Arch 2014; 467:959-72. [PMID: 25482672 DOI: 10.1007/s00424-014-1664-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/17/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
Abstract
Members of the two-pore domain K(+) channel (K2P) family are increasingly recognized as being potential targets for therapeutic drugs and could play a role in the diagnosis and treatment of neurologic disorders. Their broad and diverse expression pattern in pleiotropic cell types, importance in cellular function, unique biophysical properties, and sensitivity toward pathophysiologic parameters represent the basis for their involvement in disorders of the central nervous system (CNS). This review will focus on multiple sclerosis (MS) and stroke, as there is growing evidence for the involvement of K2P channels in these two major CNS disorders. In MS, TASK1-3 channels are expressed on T lymphocytes and are part of a signaling network regulating Ca(2+)- dependent pathways that are mandatory for T cell activation, differentiation, and effector functions. In addition, TASK1 channels are involved in neurodegeneration, resulting in autoimmune attack of CNS cells. On the blood-brain barrier, TREK1 channels regulate immune cell trafficking under autoinflammatory conditions. Cerebral ischemia shares some pathophysiologic similarities with MS, including hypoxia and extracellular acidosis. On a cellular level, K2P channels can have both proapoptotic and antiapoptotic effects, either promoting neurodegeneration or protecting neurons from ischemic cell death. TASK1 and TREK1 channels have a neuroprotective effect on stroke development, whereas TASK2 channels have a detrimental effect on neuronal survival under ischemic conditions. Future research in preclinical models is needed to provide a more detailed understanding of the contribution of K2P channel family members to neurologic disorders, before translation to the clinic is an option.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, University of Münster, Münster, Germany,
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Chapman NM, Yoder AN, Barbón KM, Bilal MY, Connolly SF, Houtman JCD. Proline-rich tyrosine kinase 2 controls PI3-kinase activation downstream of the T cell antigen receptor in human T cells. J Leukoc Biol 2014; 97:285-96. [PMID: 25387834 DOI: 10.1189/jlb.2a1013-568rrr] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
TCR-induced signaling controls T cell activation that drives adaptive immunity against infections, but it can also induce dysfunctional T cell responses that promote pathologic disease. The PI3K pathway regulates many downstream effector responses after TCR stimulation. However, the molecular mechanisms that induce PI3K function downstream of the TCR are not fully understood. We have previously shown that Pyk2 is activated downstream of the TCR in a PI3K-independent manner. Although Pyk2 controls adhesion, proliferation, and cytokine production in T cells, the mechanisms by which it controls these processes are not known. In this study, we generated Pyk2-deficient human T cells to elucidate further the role that this kinase plays in TCR-induced effector functions and signaling. We observed that Pyk2 localized with the p85 regulatory subunit of PI3K at the LAT complex and that PI3K-dependent signaling was impaired in Pyk2-deficient T cells. Likewise, functions downstream of PI3K, including IFN-γ production and proliferation, were also suppressed in human T cells deficient in Pyk2. Collectively, these data demonstrate that Pyk2 is a critical regulator of PI3K function downstream of the TCR.
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Affiliation(s)
- Nicole M Chapman
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ashley N Yoder
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Kathryn M Barbón
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Mahmood Y Bilal
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Sean F Connolly
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Jon C D Houtman
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Pankratz S, Bittner S, Herrmann AM, Schuhmann MK, Ruck T, Meuth SG, Wiendl H. Human CD4+ HLA-G+ regulatory T cells are potent suppressors of graft-versus-host disease in vivo. FASEB J 2014; 28:3435-45. [PMID: 24744146 DOI: 10.1096/fj.14-251074] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
CD4(+) T cells expressing the immunotolerizing molecule HLA-G have been described as a unique human thymus-derived regulatory T (tTreg) cell subset involved in immunoregulation and parenchymal homeostasis during infectious and autoimmune inflammation. We compared properties and molecular characteristics of human CD4(+)HLA-G(+) with those of CD4(+)CD25(+)FoxP3-expressing tTreg cells using in vitro studies of T-cell receptor (TCR) signaling, single-cell electrophysiology, and functional in vivo studies. Both tTreg populations are characterized by alterations in proximal-signaling pathways on TCR stimulation and a hyperpolarization of the plasma membrane when compared to conventional CD4(+) T cells. However, both clearly differ in phenotype and pattern of secreted cytokines, which results in distinct mechanisms of suppression: While CD4(+)HLA-G(+) cells secrete high levels of inhibitory molecules (IL-10, soluble HLA-G, IL-35), CD4(+)CD25(+)FoxP3(+) cells express these molecules at significantly lower levels and seem to exert their function mainly in a contact-dependent manner via cyclic adenosine-monophosphate. Finally we demonstrate that human CD4(+)HLA-G(+) tTreg cells significantly ameliorated graft-versus-host disease in a humanized mouse model as a first proof of their in vivo relevance. Our data further characterize and establish CD4(+)HLA-G(+) cells as a potent human tTreg population that can modulate polyclonal adaptive immune responses in vivo and thus being a promising candidate for potential clinical applications in the future.
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Affiliation(s)
| | | | | | | | | | - Sven G Meuth
- Department of Neurology and Institute of Physiology I, Department of Neuropathophysiology, University of Münster, Münster, Germany; and
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Palmitoylated transmembrane adaptor proteins in leukocyte signaling. Cell Signal 2014; 26:895-902. [PMID: 24440308 DOI: 10.1016/j.cellsig.2014.01.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 12/14/2022]
Abstract
Transmembrane adaptor proteins (TRAPs) are structurally related proteins that have no enzymatic function, but enable inducible recruitment of effector molecules to the plasma membrane, usually in a phosphorylation dependent manner. Numerous surface receptors employ TRAPs for either propagation or negative regulation of the signal transduction. Several TRAPs (LAT, NTAL, PAG, LIME, PRR7, SCIMP, LST1/A, and putatively GAPT) are known to be palmitoylated that could facilitate their localization in lipid rafts or tetraspanin enriched microdomains. This review summarizes expression patterns, binding partners, signaling pathways, and biological functions of particular palmitoylated TRAPs with an emphasis on the three most recently discovered members, PRR7, SCIMP, and LST1/A. Moreover, we discuss in silico methodology used for discovery of new family members, nature of their binding partners, and microdomain localization.
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Cruz-Orcutt N, Vacaflores A, Connolly SF, Bunnell SC, Houtman JCD. Activated PLC-γ1 is catalytically induced at LAT but activated PLC-γ1 is localized at both LAT- and TCR-containing complexes. Cell Signal 2014; 26:797-805. [PMID: 24412752 DOI: 10.1016/j.cellsig.2013.12.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 12/31/2013] [Indexed: 12/27/2022]
Abstract
Phospholipase C-γ1 (PLC-γ1) is a key regulator of T cell receptor (TCR)-induced signaling. Activation of the TCR enhances PLC-γ1 enzymatic function, resulting in calcium influx and the activation of PKC family members and RasGRP. The current model is that phosphorylation of LAT tyrosine 132 facilitates the recruitment of PLC-γ1, leading to its activation and function at the LAT complex. In this study, we examined the phosphorylation kinetics of LAT and PLC-γ1 and the cellular localization of activated PLC-γ1. We observed that commencement of the phosphorylation of LAT tyrosine 132 and PLC-γ1 tyrosine 783 occurred simultaneously, supporting the current model. However, once begun, PLC-γ1 activation occurred more rapidly than LAT tyrosine 132. The association of LAT and PLC-γ1 was more transient than the interaction of LAT and Grb2 and a pool of activated PLC-γ1 translocated away from LAT to cellular structures containing the TCR. These studies demonstrate that LAT and PLC-γ1 form transient interactions that catalyze the activation of PLC-γ1, but that activated PLC-γ1 resides in both LAT and TCR clusters. Together, this work highlights that our current model is incomplete and the activation and function of PLC-γ1 in T cells is highly complex.
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Affiliation(s)
- Noemi Cruz-Orcutt
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Aldo Vacaflores
- Interdisciplinary Graduate Program in Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Sean F Connolly
- Interdisciplinary Graduate Program in Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Stephen C Bunnell
- Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, United States; Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Jon C D Houtman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Interdisciplinary Graduate Program in Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
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Masi G, Baldari CT. Signaling at the immune synapse: vesicular trafficking takes the stage. Cell Mol Immunol 2013; 10:459-62. [PMID: 24037185 DOI: 10.1038/cmi.2013.42] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 07/23/2013] [Indexed: 12/25/2022] Open
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Multipoint binding of the SLP-76 SH2 domain to ADAP is critical for oligomerization of SLP-76 signaling complexes in stimulated T cells. Mol Cell Biol 2013; 33:4140-51. [PMID: 23979596 DOI: 10.1128/mcb.00410-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The adapter molecules SLP-76 and LAT play central roles in T cell activation by recruiting enzymes and other adapters into multiprotein complexes that coordinate highly regulated signal transduction pathways. While many of the associated proteins have been characterized, less is known concerning the mechanisms of assembly for these dynamic and potentially heterogeneous signaling complexes. Following T cell receptor (TCR) stimulation, SLP-76 is found in structures called microclusters, which contain many signaling complexes. Previous studies showed that a mutation to the SLP-76 C-terminal SH2 domain nearly abolished SLP-76 microclusters, suggesting that the SH2 domain facilitates incorporation of signaling complexes into microclusters. S. C. Bunnell, A. L. Singer, D. I. Hong, B. H. Jacque, M. S. Jordan, M. C. Seminario, V. A. Barr, G. A. Koretzky, and L. E. Samelson, Mol. Cell. Biol., 26:7155-7166, 2006). Using biophysical methods, we demonstrate that the adapter, ADAP, contains three binding sites for SLP-76, and that multipoint binding to ADAP fragments oligomerizes the SLP-76 SH2 domain in vitro. These results were complemented with confocal imaging and functional studies of cells expressing ADAP with various mutations. Our results demonstrate that all three binding sites are critical for SLP-76 microcluster assembly, but any combination of two sites will partially induce microclusters. These data support a model whereby multipoint binding of SLP-76 to ADAP facilitates the assembly of SLP-76 microclusters. This model has implications for the regulation of SLP-76 and LAT microclusters and, as a result, T cell signaling.
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