GTP-binding membrane proteins in activated and differentiating T cells.
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.
Pessa-Morikawa
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T
Department of Pathology, University of Helsinki, Finland.
Nordström
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T
Mustelin
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T
Andersson
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LC
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
D008565:Membrane Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate