This proposal considers the basic hypothesis that specific isoforms of protein kinase C (PKC), in concert with Ca2+ and diacylglycerol (DAG), play key roles in the regulation of amylase release by isolated rat parotid cells. Having already identified PKC-alpha, -delta, and -zeta isoforms, we will characterize their subcellular sites of activation (with regard to plasma and nuclear membranes, cytoskeleton) in response to receptor agonists (carbachol, norepinephrine, substance P), Ca2+, and several phorbol esters. By taking advantage of the differences in Ca2+ sensitivity and stimulus-specific isozyme activation, we will determine whether particular PKC isozymes are linked to amylase secretion. PKC will be measured by exogenous substrate phosphorylation and isozymes determined by immunoblot (Western) analysis. Phorbol ester-induced down-regulation and selective PKC inhibitors will also be employed to analyze the functional consequences of selective inhibition of particular subtypes on evoked amylase secretion. Measurement of the RNA message using Northern analysis will identify the genes of the various PKC isoforms which are expressed in the parotid cell. To assess the functional role of DAG- induced activation of PKC, the effects of pharmacologic agents that inhibit DAG lipase and kinase on NE-, CCh-, or substance P-stimulated PKC activity (exogenous substrate phosphorylation), translocation of PKC isozymes, and amylase will be studied. Since cAMP mediates amylase release via a Ca2+-dependent process, we will also examine the effects of the beta agonist isoproterenol, forskolin, and cAMP analogs on agonist- induced translocation of PKC isoforms. These studies should fortify the concept that phosphoinositide-derived messengers (Ca2+ and diacylglycerol), together with cAMP, underlie the integrative actions of receptor agonists on amylase secretion by the parotid gland. These findings should also provide salient information concerning the role of salivary secretion in dental health.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
2R01DE005764-13
Application #
2129260
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
1980-04-01
Project End
1999-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
13
Fiscal Year
1994
Total Cost
Indirect Cost
Name
State University of New York at Buffalo
Department
Pharmacology
Type
Schools of Dentistry
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
Zhu, Y; Aletta, J M; Wen, J et al. (1998) Rat serum induces a differentiated phenotype in a rat parotid acinar cell line. Am J Physiol 275:G259-68
Terzian, A R; Zhang, X; Rubin, R P (1996) Differential modulation of protein kinase C isozymes in rat parotid acinar cells. Relation to amylase secretion. Biochem Pharmacol 52:569-77
Withiam-Leitch, M; Rubin, R P; Koshlukova, S E et al. (1995) Identification and characterization of carboxyl ester hydrolase as a phospholipid hydrolyzing enzyme of zymogen granule membranes from rat exocrine pancreas. J Biol Chem 270:3780-7
Koshlukova, S; Rubin, R P; Withiam-Leitch, M et al. (1995) Epidermal growth factor induces the differential release of GP2 and amylase from AR4-2J cells. Cell Signal 7:559-69
Rubin, R P; Adolf, M A (1994) Cyclic AMP regulation of calcium mobilization and amylase release from isolated permeabilized rat parotid cells. J Pharmacol Exp Ther 268:600-6
Withiam-Leitch, M; Aletta, J M; Koshlukova, S E et al. (1993) Glycoprotein 2 of zymogen granule membranes shares immunological cross-reactivity and sequence similarity with phospholipase A2. Biochem Biophys Res Commun 194:1167-74
Terzian, A R; Rubin, R P (1993) Translocation of the alpha-isozyme of protein kinase C during stimulation of rat parotid acinar cells by phorbol ester and carbachol. Arch Oral Biol 38:1051-6
Chaudhry, A; Rubin, R P (1990) Mediators of Ca2(+)-dependent secretion. Environ Health Perspect 84:35-9
McKinney, J S; Desole, M S; Rubin, R P (1989) Convergence of cAMP and phosphoinositide pathways during rat parotid secretion. Am J Physiol 257:C651-7
McKinney, J S; Rubin, R P (1988) Enhancement of cyclic AMP modulated salivary amylase secretion by protein kinase C activators. Biochem Pharmacol 37:4433-8

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