Localization of beta II subspecies of protein kinase C in beta-cells.
Protein kinase C (PKC) has been generally accepted to play a key role in stimulus-response coupling in various secretory cells, including pancreatic islets and pancreatic acini. The enzyme exists as a large family of multiple subspecies with highly related structures (alpha-, beta I-, beta II-, gamma-, delta-, epsilon-, and zeta-PKC). With an immunocytochemical procedure with subspecies-specific antibodies, beta II-PKC-like immunoreactivity was identified to localize in the beta-cells of the rat pancreatic islets. Neither beta I- nor gamma-PKC-like immunoreactivity was found in both islets and acini. Biochemical analysis confirmed that the rat whole pancreatic tissues contain a significant amount of alpha-PKC and a minute amount of beta II-PKC but neither beta I- nor gamma-PKC. On the other hand, beta II-PKC-like immunoreactivity was not detected in rat insulinoma cells, in which insulin secretion was induced in response to 12-O-tetradecanoylphorbol-13-acetate and carbachol but not in response to glucose. These findings suggest that beta II-PKC is the major, if not the sole, subspecies of PKC in beta-cells of rat pancreatic islets and a possible candidate for involvement in glucose-induced insulin secretion.
Ito
A
A
Department of Pharmacology, Kobe University School of Medicine, Japan.
Saito
N
N
Taniguchi
H
H
Chiba
T
T
Kikkawa
U
U
Saitoh
Y
Y
Tanaka
C
C
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002217:Carbachol / Q000494:pharmacology; D005260:Female; D005947:Glucose / Q000494:pharmacology; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007340:Insulinoma / Q000378:metabolism / Q000473:pathology; D007515:Islets of Langerhans / Q000032:analysis / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011493:Protein Kinase C / Q000032:analysis / Q000145:classification / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology
D000911:Antibodies, Monoclonal; D007328:Insulin; D002217:Carbachol; D011493:Protein Kinase C; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate