Phytohemagglutinin treatment of T lymphocytes stimulates rapid increases in activity of both particulate and cytosolic protein kinase C.
We have measured the activity of protein kinase C in particulate and cytosolic fractions prepared from lymphocytes following stimulation with phytohemagglutinin. Activity in the particulate fraction increased approximately three-fold within 5 min, and declined to nearly zero between 20 and 60 min. Cytosolic activity increased in a biphasic manner, with an initial increase at 5 min, a decline at 10 min, and a further increase by 20 min, which was sustained for at least 60 min. By contrast, 12-O-tetradecanoylphorbol-13-acetate caused a rapid translocation of protein kinase C from cytosol to the particulate fraction which was sustained for at least 1 h. The results suggest that agents, such as phytohemagglutinin, which both generate diacylglycerol and mobilize intracellular Ca2+ stores, result in changes in subcellular distribution and activity of protein kinase C which are different from those elicited by 12-O-tetradecanoylphorbol-13-acetate.
D002451:Cell Compartmentation / Q000187:drug effects; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008213:Lymphocyte Activation; D008566:Membranes / Q000378:metabolism; D010704:Phorbols / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*; D012995:Solubility; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D010704:Phorbols; D010835:Phytohemagglutinins; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate