title: GTP-binding membrane proteins in activated and differentiating T cells.
abstract: We have earlier reported changes in the GTP binding of several membrane proteins including Gs alpha and Gi alpha during thymic differentiation of T cells. Using an [alpha-32P]GTP-photoaffinity labeling technique we have studied the pattern of GTP binding proteins in activated and resting T lymphocytes and in T cells induced to differentiate by TPA. The GTP binding proteins in mitogen-activated T cells resembled those seen in leukemia T cell lines. Treatment of Jurkat, but not of CCRF-CEM, T cells with TPA caused increased GTP-labeling of a 34 kDa protein and Gi alpha. The GTP labeling pattern in TPA-treated Jurkat cells resembled that in resting T lymphocytes. TPA induced de novo expression of functional TCR/CD3 on CCRF-CEM and downregulation of TCR/CD3 on Jurkat cells but these changes did not correlate with the altered GTP-labeling patterns.
authors.affiliation: Department of Pathology, University of Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Pessa-Morikawa
authors.forename: T
authors.initials: T
authors.lastname: Nordström
authors.forename: T
authors.initials: T
authors.lastname: Mustelin
authors.forename: L C
authors.initials: LC
authors.lastname: Andersson
mesh_terms: D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D005434:Flow Cytometry; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D008565:Membrane Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate