Effects of protein kinase C activators and staurosporine on protein kinase activity, cell survival, and proliferation in Tetrahymena thermophila.
Autocrine factors prevent cell death in the ciliate Tetrahymena thermophila, a unicellular eukaryote, in a chemically defined medium. At certain growth conditions these factors are released at a sufficient concentration by > 500 cells ml-1 to support cell survival and proliferation. The protein kinase C activators phorbol 12-myristate 13-acetate (PMA) or 1-oleyl 2-acetate glycerol (OAG) when added to 250 cells ml-1 supported cell survival and proliferation. In the presence of the serine and threonine kinase inhibitor staurosporine the cells died both at 250 cells ml-1 in cultures supplemented with either PMA or OAG, or at 2,500 cells ml-1. At 500 cells ml-1 PMA induced the in vivo phosphorylation of at least six proteins. The myelin basic protein fragment 4-14 was phosphorylated in vitro in crude extracts of a culture of 250,000 cells ml-1. Both the in vivo and the in vitro phosphorylation were inhibited by staurosporine.
Straarup
E M
EM
Department of Anatomy and Cell Biology, Odense University, Denmark.
Schousboe
P
P
Hansen
H Q
HQ
Kristiansen
K
K
Hoffmann
E K
EK
Rasmussen
L
L
Christensen
S T
ST
D000818:Animals; D001345:Autoradiography; D003436:Croton Oil / Q000378:metabolism / Q000494:pharmacology; D004075:Diglycerides / Q000378:metabolism / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004676:Myelin Basic Protein / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019311:Staurosporine / Q000378:metabolism / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology*; D016808:Tetrahymena thermophila / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development
D004075:Diglycerides; D004791:Enzyme Inhibitors; D004676:Myelin Basic Protein; D003436:Croton Oil; C038237:1-oleoyl-2-acetylglycerol; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate