Evidence for GTP-binding protein involvement in the tyrosine phosphorylation of the T cell receptor zeta chain.
The zeta subunit of the T cell receptor (TCR) is a prominent substrate for a TCR-activated tyrosine kinase. Tyrosine phosphorylation of the zeta subunit in response to antibody-mediated receptor cross-linking was synergized in permeabilized T cells by either of two non-hydrolyzable GTP analogues, guanosine 5'-[gamma-thio]triphosphate (GTP gamma S) or guanosine 5'-[beta, gamma-imido]triphosphate Gpp(NH)p. ATP analogues did not significantly affect antibody-induced tyrosine phosphorylation. Unlike the GTP analogues, the GDP analogue guanosine 5'-[beta-thio]diphosphate (GDP beta S) did not enhance phosphorylation of zeta. The effect induced by the GTP analogues required TCR occupancy and was independent of protein kinase C. Taken together these observations implicate a GTP-binding protein in the modulation of TCR-induced tyrosine phosphorylation.
Cenciarelli
C
C
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
Hohman
R J
RJ
Atkinson
T P
TP
Gusovsky
F
F
Weissman
A M
AM
D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013873:Thionucleotides / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D016692:Receptors, Antigen, T-Cell, gamma-delta; D013873:Thionucleotides; D006153:Guanosine Diphosphate; C032829:6-thioguanosine 5'-diphosphate; D006165:Guanylyl Imidodiphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D014443:Tyrosine; D019204:GTP-Binding Proteins; D013755:Tetradecanoylphorbol Acetate