title: Negative regulation of T cell receptor-lipid raft interaction by cytotoxic T lymphocyte-associated antigen 4.
abstract: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is an essential negative regulator of T cell activation. Recent evidence suggests that CTLA-4 association with the immunological synapse during contact with antigen-presenting cells is important for its inhibitory function. In the present study, we observed a direct interaction of CTLA-4 with the phosphorylated form of T cell receptor (TCR)zeta within the glycolipid-enriched microdomains associated with the T cell signaling complex. In this setting, CTLA-4 regulated the accumulation/retention of TCRzeta in the signaling complex, as the lipid raft fractions from CTLA-4KO T cells contained significantly higher amounts of the TCR components when compared with wild-type littermates. In contrast, coligation of CTLA-4 with the TCR during T cell activation selectively decreased the amount of TCRzeta that accumulated in the rafts. These results suggest that CTLA-4 functions to regulate T cell signaling by controlling TCR accumulation and/or retention within this a critical component of the immunological synapse.
authors.affiliation: Diabetes Center, University of California at San Francisco, San Francisco, CA 94143, USA.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Chikuma
authors.forename: John B
authors.initials: JB
authors.lastname: Imboden
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Bluestone
mesh_terms: D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism; D060908:CTLA-4 Antigen; D017353:Gene Deletion; D006801:Humans; D018796:Immunoconjugates; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D017252:CD3 Complex; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D000069594:Abatacept