Cholecystokinin (CCK) stimulates S6 phosphorylation and induced activation of S6 protein kinase in rat pancreatic acini
CCK and insulin stimulate pancreatic protein synthesis at a post transcriptional step. To better understand this regulation the authors evaluated the phosphorylation state of ribosomal protein S6 and the presence of a specific S6 protein kinase in pancreatic acini from diabetic rats. Both CCK and insulin increased S6 phosphorylation by up to 400% in intact TSP-labelled acini. The phorbol ester 12-0-tetradecanoylphorbol 13-acetate also stimulated both protein synthesis and S6 phosphorlyation suggesting a role for protein kinase C in mediating the effect of CCK. By contrast, the CaS ionophore ionomycin had no effect on either parameter. Recently, insulin has been shown to activate a unique S6 kinase in various cells. To test for its presence, cytosolic extracts were prepared from acini stimulated with CCK and insulin by homogenization in US -glycerophosphate buffer and assayed for the kinase using el-TSP ATP and rat pancreatic ribosomes followed by SDS-polyacrylamide gel electrophoresis. CCK and insulin both increased S6 kinase activity which required neither CaS or phospholipid. The dose response for CCk was similar to S6 phosphorlyation in the intact acini. TPA did not stimulate the S6 kinase. Thus, CCK may induce S6 phosphorylation both via C kinase and by activation of a unique S6 kinase.
- Research Organization:
- Univ. of California, San Francisco
- OSTI ID:
- 6279434
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
ATP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
CARCINOGENS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DIABETES MELLITUS
DIGESTIVE SYSTEM
DISEASES
DOSE-RESPONSE RELATIONSHIPS
ELECTROPHORESIS
ENDOCRINE DISEASES
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYMES
ESTERS
GLANDS
HORMONES
INSULIN
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
KININS
LIGHT NUCLEI
MAMMALS
METABOLIC DISEASES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PANCREAS
PATHOGENESIS
PEPTIDE HORMONES
PEPTIDES
PHORBOL ESTERS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
POLYPEPTIDES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES