Possible involvement of atypical protein kinase C (PKC) in glucose-sensitive expression of the human insulin gene: DNA-binding activity and transcriptional activity of pancreatic and duodenal homeobox gene-1 (PDX-1) are enhanced via calphostin C-sensitive but phorbol 12-myristate 13-acetate (PMA) and Gö 6976-insensitive pathway.

摘要: Pancreatic and duodenal homeobox gene-1(PDX-1) is a transcription factor which regulates the insulin gene expression. In this study, we tried to elucidate role of PDX-1 in glucose-induced transcriptional activation human promoter MINE cells. Electrophoretic mobility shift assay (EMSA) chloramphenicol acetyltransferase (CAT) demonstrated that both DNA-binding activity were increased with 20mmol/l glucose more than 2mmol/l glucose. The induced by high was blocked phosphatase treatment, suggesting involvement phosphorylation event. an vitro phosphorylated protein kinase C (PKC), but not cAMP dependent (PKA) or mitogen-activated (MAPK). Furthermore, function calphostin C, inhibitor all PKC isoforms, unaffected phorbol 12-myristate 13-acetate (PMA), activator classical novel PKC, Go 6976, suggested family activated cells atypical PKC. Western blot immunocytochemical studies anti-PKCζ antibody confirmed presence ζ, one isoforms MIN6 ζ significantly stimulation. These results suggest activating including resulting promoter.