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This Article Full Text Full Text (PDF) Supplemental Figures All Versions of this Article: 295/6/G1190    most recent 90452.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yuan, J. Articles by Pandol, S. J. PubMed PubMed Citation Articles by Yuan, J. Articles by Pandol, S. J.

HORMONES AND SIGNALING

Protein kinase D1 mediates NF-B activation induced by cholecystokinin and cholinergic signaling in pancreatic acinar cells

¹Veterans Affairs Greater Los Angeles Healthcare System; ²USC-UCLA Research Center for Alcoholic Liver and Pancreatic Diseases; and ³CURE: Digestive Diseases Research Center, University of California at Los Angeles, California

Submitted 23 July 2008 ; accepted in final form 5 October 2008

The transcription factor NF-B plays a critical role in inflammatory and cell death responses during acute pancreatitis. Previous studies in our laboratory demonstrated that protein kinase C (PKC) isoforms PKC and are key regulators of NF-B activation induced by cholecystokinin-8 (CCK-8), tumor necrosis factor-, and ethanol. However, the downstream participants in regulating NF-B activation in exocrine pancreas remain poorly understood. Here, we demonstrate that protein kinase D1 (PKD1) is a key downstream target of PKC and PKC in pancreatic acinar cells stimulated by two major secretagogues, CCK-8 and the cholinergic agonist carbachol (CCh), and that PKD1 is necessary for NF-B activation induced by CCK-8 and CCh. Both CCK-8 and CCh dose dependently induced a rapid and striking activation of PKD1 in rat pancreatic acinar cells, as measured by in vitro kinase assay and by phosphorylation at PKD1 activation loop (Ser744/748) or autophosphorylation site (Ser916). The phosphorylation and activation of PKD1 correlated with NF-B activity stimulated by CCK-8 or CCh, as measured by NF-B DNA binding. Either inhibition of PKC or by isoform-specific inhibitory peptides, genetic deletion of PKC and in pancreatic acinar cells, or knockdown of PKD1 by using small interfering RNAs in AR42J cells resulted in a marked decrease in PKD1 and NF-B activation stimulated by CCK-8 or CCh. Conversely, overexpression of PKD1 resulted in augmentation of CCK-8- and CCh-stimulated NF-B activation. Finally, the kinetics of PKD1 and NF-B activation during cerulein-induced rat pancreatitis showed that both PKD1 and NF-B activation were early events during acute pancreatitis and that their time courses of response were similar. Our results identify PKD1 as a novel early convergent point for PKC and in the signaling pathways mediating NF-B activation in pancreatitis.

PKC delta; PKC epsilon; pancreatitis; carbachol; cerulein