Cytochalasin E enhances the protein kinase C-dependent process of secretion.
Platelet dense body secretion, monitored as released serotonin, when induced by 20 nM tetradecanoylphorbol acetate was enhanced by 10 microM cytochalasin E even in the absence of external calcium ions and aggregation. Secretion induced by 500 nM A23187 in the presence of 15 microM indomethacin was not changed by cytochalasin but the synergy between A23187 and phorbol ester was enhanced. Therefore, protein kinase C-mediated secretion is not dependent on filipodal development, granule centralization, external calcium ion concentration or aggregation but is enhanced selectively by cytochalasin. Because the synergy between kinase C and A23187 is very rapid, the rate determining step in the slow secretion induced by phorbol ester alone appears to be the step accelerated by a rise in cytosolic Ca2+ concentration.
Cox
A C
AC
Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003572:Cytochalasins / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D009183:Mycotoxins / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects; D011493:Protein Kinase C / Q000097:blood*; D012701:Serotonin / Q000097:blood; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D003572:Cytochalasins; D009183:Mycotoxins; D012701:Serotonin; C007215:cytochalasin E; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate