G proteins in T cell signal transduction.
This review summarises recent data on G protein implication in receptor signalling in T cells. The data show that PPI-specific PLC in T cell membranes is under G protein control. Some evidence indicates that a G protein couples PLC to TCR. Differences are revealed between the effects induced by direct G protein activators, such as GTP gamma S or AlF4-, and TCR ligands, which imply that TCR ligands may trigger some G-protein-independent signals. An analysis of the conflicting results on the action of PTX and CTX, one of the main tools in studying G proteins, has shown that the toxins produce both G protein-dependent and independent effects. The G protein which couples PLC to TCR appears insensitive to both PTX and CTX. Some findings suggest G protein involvement in signalling induced by interleukins; however, in this case the effector molecules implicate often remain unknown. Scarce data on G protein involvement in signalling from differentiation antigens, on direct G protein regulation of ion channels, and on identification of G proteins in T cells, are also discussed.
Gukovskaya
A S
AS
Institute of Theoretical and Experimental Biophysics, USSR Academy of Sciences, Pushchino, Moscow Region.
D000818:Animals; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D010716:Phosphatidylinositols / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
D010716:Phosphatidylinositols; D011948:Receptors, Antigen, T-Cell; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins