CCK2 (CCK(B)/gastrin) receptor mediates rapid protein kinase D (PKD) activation through a protein kinase C-dependent pathway.
Addition of gastrin or cholecystokinin octapeptide (CCK-8) to cultures of Rat-1 cells stably transfected with the CCK2 (CCK(B)/gastrin) receptor induced protein kinase D (PKD) activation that was detectable within 1 min and reached a maximum ( approximately 10-fold) after 2.5 min of hormonal stimulation. Half-maximal PKD activation for both CCK-8 and gastrin was achieved at 10 nM. Treatment with various concentrations of the selective PKC inhibitors Ro 31-8220 or GF-I potently blocked PKD activation induced by subsequent addition of CCK-8 in a concentration-dependent fashion. Our results indicate that PKC-dependent PKD activation is a novel early event in the action of gastrin and CCK-8 via CCK2 receptors.
Department of Medicine, UCLA School of Medicine and Molecular Biology Institute, 900 Veteran Avenue, Warren Hall, Room 11-124, University of California, Los Angeles, CA 90095-1786, USA.
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Chiu
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Rozengurt
D000818:Animals; D002478:Cells, Cultured; D004789:Enzyme Activation; D005755:Gastrins / Q000378:metabolism; D006801:Humans; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000378:metabolism*; D012844:Sincalide / Q000378:metabolism; D014162:Transfection
D005755:Gastrins; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; C089212:protein kinase D; D011493:Protein Kinase C; D012844:Sincalide