title: Proinsulin C-peptide activates cAMP response element-binding proteins through the p38 mitogen-activated protein kinase pathway in mouse lung capillary endothelial cells.
abstract: Proinsulin C-peptide has been reported to have some biological activities and to be possibly involved in the development of diabetic microangiopathy. In the present study, we examined the effects of C-peptide on the mitogen-activated protein kinase pathway in LEII mouse lung capillary endothelial cells. Stimulation of the cells with C-peptide increased both p38 mitogen-activated protein kinase (p38MAPK) and extracellular signal-regulated kinase (ERK1/2) activities and activity-related site-specific phosphorylation of the respective kinases in a concentration-dependent manner, but failed to activate c-Jun N-terminal kinase. Stimulation of the cells with C-peptide also induced site-specific phosphorylation of cAMP response element (CRE)-binding protein (CREB)/activating transcription factor 1 (ATF1), and thereby binding of these transcription factors to CRE. Among three CREB kinases tested, phosphorylation of mitogen-activated protein kinase-activated protein kinase 2 (MAPKAP-K2) was induced after stimulation with C-peptide. The phosphorylation of CREB, ATF1 and MAPKAP-K2 were inhibited by SB203580, a p38MAPK inhibitor, but not by PD98059, an ERK kinase inhibitor. These results indicate that C-peptide activates p38MAPK followed by MAPKAP-K2 to enhance DNA-CREB/ATF1 interactions.
authors.affiliation: Laboratory of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kitamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Bae Dong
authors.initials: BD
authors.lastname: Jung
authors.forename: Kennedy
authors.initials: K
authors.lastname: Makondo
authors.forename: Naoki
authors.initials: N
authors.lastname: Sakane
authors.forename: Toshihide
authors.initials: T
authors.lastname: Yoshida
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saito
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002096:C-Peptide / Q000378:metabolism*; D002196:Capillaries / Q000201:enzymology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002096:C-Peptide; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D007328:Insulin; D014157:Transcription Factors; D000242:Cyclic AMP; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases