Translocation of the alpha-isozyme of protein kinase C during stimulation of rat parotid acinar cells by phorbol ester and carbachol.
Protein kinase C activity was detected in the cytosolic fraction of quiescent parotid acinar cells; the particulate fraction contained a much smaller proportion of the enzyme. Protein kinase C activity was increased in the membrane fraction and decreased in the cytosol after exposure of intact cells to phorbol 12-myristate 13-acetate (PMA) or the muscarinic-receptor agonist carbachol. The effect of PMA was potentiated by a subthreshold concentration of ionomycin. Immunoblot analysis with anti-protein kinase C antibodies revealed that the protein kinase C-alpha isoform is expressed in rat parotid cells. Other Ca(2+)-dependent isoforms were not detected. Further, agonist stimulation caused the redistribution of protein kinase C-alpha from cytosol to a membrane fraction. Agonists may promote parotid acinar cell activity, including amylase secretion, by increasing the affinity of protein kinase C-alpha for the membrane fraction, presumably via a rise in Ca2+ and diacylglycerol derived from polyphosphoinositide hydrolysis.
Terzian
A R
AR
Department of Pharmacology and Therapeutics, State University of New York at Buffalo 14214.
Rubin
R P
RP
D000704:Analysis of Variance; D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology*; D002352:Carrier Proteins; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000096:biosynthesis; D004789:Enzyme Activation; D015759:Ionomycin / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D010306:Parotid Gland / Q000187:drug effects / Q000201:enzymology* / Q000294:innervation; D010703:Phorbol Esters / Q000494:pharmacology*; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000187:drug effects; D012471:Salivary Proteins and Peptides / Q000378:metabolism; D015398:Signal Transduction; D000516:alpha-Amylases / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D004075:Diglycerides; D007527:Isoenzymes; D010703:Phorbol Esters; D011955:Receptors, Drug; D012471:Salivary Proteins and Peptides; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015759:Ionomycin; D002217:Carbachol; D011493:Protein Kinase C; D000516:alpha-Amylases; D002118:Calcium