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Yablonski D. Bridging the Gap: Modulatory Roles of the Grb2-Family Adaptor, Gads, in Cellular and Allergic Immune Responses. Front Immunol 2019; 10:1704. [PMID: 31402911 PMCID: PMC6669380 DOI: 10.3389/fimmu.2019.01704] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/08/2019] [Indexed: 01/07/2023] Open
Abstract
Antigen receptor signaling pathways are organized by adaptor proteins. Three adaptors, LAT, Gads, and SLP-76, form a heterotrimeric complex that mediates signaling by the T cell antigen receptor (TCR) and by the mast cell high affinity receptor for IgE (FcεRI). In both pathways, antigen recognition triggers tyrosine phosphorylation of LAT and SLP-76. The recruitment of SLP-76 to phospho-LAT is bridged by Gads, a Grb2 family adaptor composed of two SH3 domains flanking a central SH2 domain and an unstructured linker region. The LAT-Gads-SLP-76 complex is further incorporated into larger microclusters that mediate antigen receptor signaling. Gads is positively regulated by dimerization, which promotes its cooperative binding to LAT. Negative regulation occurs via phosphorylation or caspase-mediated cleavage of the linker region of Gads. FcεRI-mediated mast cell activation is profoundly impaired in LAT- Gads- or SLP-76-deficient mice. Unexpectedly, the thymic developmental phenotype of Gads-deficient mice is much milder than the phenotype of LAT- or SLP-76-deficient mice. This distinction suggests that Gads is not absolutely required for TCR signaling, but may modulate its sensitivity, or regulate a particular branch of the TCR signaling pathway; indeed, the phenotypic similarity of Gads- and Itk-deficient mice suggests a functional connection between Gads and Itk. Additional Gads binding partners include costimulatory proteins such as CD28 and CD6, adaptors such as Shc, ubiquitin regulatory proteins such as USP8 and AMSH, and kinases such as HPK1 and BCR-ABL, but the functional implications of these interactions are not yet fully understood. No interacting proteins or function have been ascribed to the evolutionarily conserved N-terminal SH3 of Gads. Here we explore the biochemical and functional properties of Gads, and its role in regulating allergy, T cell development and T-cell mediated immunity.
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Affiliation(s)
- Deborah Yablonski
- The Immune Cell Signaling Lab, Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Yablonski D. Bridging the Gap: Modulatory Roles of the Grb2-Family Adaptor, Gads, in Cellular and Allergic Immune Responses. Front Immunol 2019; 10:1704. [PMID: 31402911 DOI: 10.3389/fimmu.2019.01704/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/08/2019] [Indexed: 05/22/2023] Open
Abstract
Antigen receptor signaling pathways are organized by adaptor proteins. Three adaptors, LAT, Gads, and SLP-76, form a heterotrimeric complex that mediates signaling by the T cell antigen receptor (TCR) and by the mast cell high affinity receptor for IgE (FcεRI). In both pathways, antigen recognition triggers tyrosine phosphorylation of LAT and SLP-76. The recruitment of SLP-76 to phospho-LAT is bridged by Gads, a Grb2 family adaptor composed of two SH3 domains flanking a central SH2 domain and an unstructured linker region. The LAT-Gads-SLP-76 complex is further incorporated into larger microclusters that mediate antigen receptor signaling. Gads is positively regulated by dimerization, which promotes its cooperative binding to LAT. Negative regulation occurs via phosphorylation or caspase-mediated cleavage of the linker region of Gads. FcεRI-mediated mast cell activation is profoundly impaired in LAT- Gads- or SLP-76-deficient mice. Unexpectedly, the thymic developmental phenotype of Gads-deficient mice is much milder than the phenotype of LAT- or SLP-76-deficient mice. This distinction suggests that Gads is not absolutely required for TCR signaling, but may modulate its sensitivity, or regulate a particular branch of the TCR signaling pathway; indeed, the phenotypic similarity of Gads- and Itk-deficient mice suggests a functional connection between Gads and Itk. Additional Gads binding partners include costimulatory proteins such as CD28 and CD6, adaptors such as Shc, ubiquitin regulatory proteins such as USP8 and AMSH, and kinases such as HPK1 and BCR-ABL, but the functional implications of these interactions are not yet fully understood. No interacting proteins or function have been ascribed to the evolutionarily conserved N-terminal SH3 of Gads. Here we explore the biochemical and functional properties of Gads, and its role in regulating allergy, T cell development and T-cell mediated immunity.
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Affiliation(s)
- Deborah Yablonski
- The Immune Cell Signaling Lab, Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Sukenik S, Frushicheva MP, Waknin-Lellouche C, Hallumi E, Ifrach T, Shalah R, Beach D, Avidan R, Oz I, Libman E, Aronheim A, Lewinson O, Yablonski D. Dimerization of the adaptor Gads facilitates antigen receptor signaling by promoting the cooperative binding of Gads to the adaptor LAT. Sci Signal 2017; 10:10/498/eaal1482. [PMID: 28951535 DOI: 10.1126/scisignal.aal1482] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The accurate assembly of signalosomes centered on the adaptor protein LAT (linker of activated T cells) is required for antigen receptor signaling in T cells and mast cells. During signalosome assembly, members of the growth factor receptor-bound protein 2 (Grb2) family of cytosolic adaptor proteins bind cooperatively to LAT through interactions with its phosphorylated tyrosine (pTyr) residues. We demonstrated the Src homology 2 (SH2) domain-mediated dimerization of the Grb2 family member, Grb2-related adaptor downstream of Shc (Gads). Gads dimerization was mediated by an SH2 domain interface, which is distinct from the pTyr binding pocket and which promoted cooperative, preferential binding of paired Gads to LAT. This SH2 domain-intrinsic mechanism of cooperativity, which we quantified by mathematical modeling, enabled Gads to discriminate between dually and singly phosphorylated LAT molecules. Mutational inactivation of the dimerization interface reduced cooperativity and abrogated Gads signaling in T cells and mast cells. The dimerization-dependent, cooperative binding of Gads to LAT may increase antigen receptor sensitivity by reducing signalosome formation at incompletely phosphorylated LAT molecules, thereby prioritizing the formation of complete signalosomes.
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Affiliation(s)
- Sigalit Sukenik
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Maria P Frushicheva
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Cecilia Waknin-Lellouche
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Enas Hallumi
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Talia Ifrach
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Rose Shalah
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Dvora Beach
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Reuven Avidan
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Ilana Oz
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Evgeny Libman
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Ami Aronheim
- Department of Cell Biology and Cancer Science, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Oded Lewinson
- Department of Biochemistry, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Deborah Yablonski
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel.
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Mitchell JL, Seng A, Yankee TM. Expression patterns of Ikaros family members during positive selection and lineage commitment of human thymocytes. Immunology 2016; 149:400-412. [PMID: 27502439 DOI: 10.1111/imm.12657] [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: 02/10/2016] [Revised: 07/19/2016] [Accepted: 08/03/2016] [Indexed: 12/12/2022] Open
Abstract
The Ikaros family of transcription factors is essential for normal T-cell development, but their expression pattern in human thymocytes remains poorly defined. Our goal is to determine how protein levels of Ikaros, Helios and Aiolos change as human thymocytes progress through the positive selection and lineage commitment stages. To accomplish this goal, we used multi-parameter flow cytometry to define the populations in which positive selection and lineage commitment are most likely to occur. After human thymocytes express CD3 and receive positive selection signals, the cells down-regulate expression of CD4 to become transitional single-positive (TSP) CD8+ thymocytes. At this stage, there was a transient increase in the Ikaros, Helios and Aiolos protein levels. After the TSP CD8+ developmental stage, some thymocytes re-express CD4 and become CD3hi double-positive thymocytes before down-regulating CD8 to become mature single-positive CD4+ thymocytes. Except for regulatory T cells, Helios protein levels declined and Aiolos protein levels transiently increased during CD4+ T-cell maturation. For thymocytes progressing toward the CD8+ T-cell lineage, TSP CD8+ thymocytes increase their expression of CD3 and maintain high levels of Aiolos protein as the cells complete their maturation. In summary, we defined the TSP CD8+ developmental stage in human T-cell development and propose that this stage is where CD4/CD8 lineage commitment occurs. Ikaros, Helios and Aiolos each undergo a transient increase in protein levels at the TSP stage before diverging in their expression patterns at later stages.
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Affiliation(s)
- Julie L Mitchell
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Amara Seng
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Thomas M Yankee
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, 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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Zhang EY, Xiong J, Parker BL, Chen AY, Fields PE, Ma X, Qiu J, Yankee TM. Depletion and recovery of lymphoid subsets following morphine administration. Br J Pharmacol 2012; 164:1829-44. [PMID: 21557737 DOI: 10.1111/j.1476-5381.2011.01475.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Opioid use and abuse has been linked to significant immunosuppression, which has been attributed, in part, to drug-induced depletion of lymphocytes. We sought to define the mechanisms by which lymphocyte populations are depleted and recover following morphine treatment in mice. EXPERIMENTAL APPROACH Mice were implanted with morphine pellets and B- and T-cell subsets in the bone marrow, thymus, spleen and lymph nodes were analysed at various time points. We also examined the effects of morphine on T-cell development using an ex vivo assay. KEY RESULTS The lymphocyte populations most susceptible to morphine-induced depletion were the precursor cells undergoing selection. As the lymphocytes recovered, more lymphocyte precursors proliferated than in control mice. In addition, peripheral T-cells displayed evidence that they had undergone homeostatic proliferation during the recovery phase of the experiments. CONCLUSIONS AND IMPLICATIONS The recovery of lymphocytes following morphine-induced depletion occurred in the presence of morphine and via increased proliferation of lymphoid precursors and homeostatic proliferation of T-cells.
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Affiliation(s)
- E Y Zhang
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Zhang EY, Parker BL, Yankee TM. Gads regulates the expansion phase of CD8+ T cell-mediated immunity. THE JOURNAL OF IMMUNOLOGY 2011; 186:4579-89. [PMID: 21411729 DOI: 10.4049/jimmunol.1001604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Gads adaptor protein is critical for TCR-mediated Ca(2+) mobilization. We investigated the effect of Gads deficiency on the proliferation of CD8(+) T cells following peptide stimulation and in the context of infection with an intracellular pathogen. We stimulated CD8(+) T cells from Gads(+/+) OT-I and Gads(-/-) OT-I mice with cognate Ag (SIINFEKL) or altered peptide ligand. In vitro experiments revealed that Gads was required for optimal proliferation of CD8(+) T cells. This defect was most evident at the early time points of proliferation and when low doses of Ag were used as stimuli. Cell cycle analysis demonstrated that Gads(-/-) CD8(+) T cells had impaired TCR-mediated exit from the G(0) phase of the cell cycle. Furthermore, Gads(-/-) CD8(+) T cells had delayed expression of c-myc and CD69 upon the stimulation with SIINFEKL. We then investigated how Gads deficiency would impact CD8(+) T cell-mediated immunity in the context of infection with an intracellular pathogen. At early time points, Gads(+/+) and Gads(-/-) CD8(+) T cells proliferated to a similar extent, despite the fact that expression of CD69 and CD25 was reduced in the absence of Gads. After 5 d postinfection, Gads was required to sustain the expansion phase of the immune response; the peak response of Gads(-/-) cells was significantly lower than for Gads(+/+) cells. However, Gads was not required for the differentiation of naive CD8(+) T cells into memory cells. We conclude that the primary function of Gads is to regulate the sensitivity of the TCR to Ag ligation.
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Affiliation(s)
- Elizabeth Yan Zhang
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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