Effect of phorbol esters on the distribution and total activity of protein kinase C in the perfused rat heart.
1. The perfused rat heart was treated with the tumour-promoter and protein kinase C activator, phorbol 12-myristate 13-acetate and the distribution of protein kinase C activity between cytosolic and particulate fractions determined. 2. Phorbol ester treatment led to a rapid loss of protein kinase C activity from the cytosol (t0.5 = 2 min) with a corresponding translocation into the particulate fraction. Translocated protein kinase C activity was tightly bound to the particulate fraction, could only be extracted with buffers containing 2% Triton X-100 and could therefore be misinterpreted as being down-regulated. 3. Claims of rapid down-regulation of protein kinase C activity by phorbol esters need to be supported by rigorous procedures for extraction of the particulate material.
Rattigan
S
S
Department of Biochemistry, University of Tasmania, Australia.
Davison
A G
AG
Cleland
P J
PJ
Clark
M G
MG
D000818:Animals; D003600:Cytosol / Q000201:enzymology; D015536:Down-Regulation; D006321:Heart / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000201:enzymology; D010477:Perfusion; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate