Proteomic analysis of O-GlcNAc modifications derived from streptozotocin and glucosamine induced beta-cell apoptosis.
The post-translational modifications of Ser and Thr residues by O-linked beta-N-acetylglucosamine (O-GlcNAc), i.e., O-GlcNAcylation, is considered a key means of regulating signaling, in a manner analogous to protein phosphorylation. Furthermore, it has been suggested that the increased flux of glucose through the hexosamine biosynthetic pathway (HBP) stimulates O-GlcNAcylation, and that this may be responsible for many of the manifestations of type 2 diabetes mellitus. To determine whether excessive O-GlcNAcylation of target proteins results in pancreatic beta cell dysfunction, we increased nucleocytoplasmic protein O-GlcNAcylation levels in beta cells by exposing them to streptozotocin and/or glucosamine. Streptozotocin and glucosamine co-treatment increased OGlcNAcylated proteomic patterns as assessed by immunoblotting, and these increases in nuclear and cytoplasmic protein O-GlcNAcylations were accompanied by impaired insulin secretion and enhanced apoptosis in pancreatic beta cells. This observed beta cell dysfunction prompted us to examine Akt and Bcl-2 family member proteins to determine which proteins are O-GlcNAcylated under conditions of high HBP throughput, and how these proteins are associated with beta cell apoptosis. Eventually, we identified ten new O-GlcNAcylated proteins that were expressed during beta cell apoptosis, and analyzed the functional implications of these proteins in relation to pancreatic beta cell dysfunction.
Cancer Research Institute and College of Medicine, Seoul National University, Yongon-Dong, Seoul 110-799, Korea.
Jungeun
J
Park
Hyejin
H
Kwon
Yup
Y
Kang
Youngsoo
Y
Kim
D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000378:metabolism; D005944:Glucosamine / Q000633:toxicity; D006031:Glycosylation / Q000187:drug effects; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D008954:Models, Biological; D010091:Oximes / Q000494:pharmacology; D048448:Phenylcarbamates / Q000494:pharmacology; D040901:Proteomics; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D013311:Streptozocin / Q000633:toxicity
D007328:Insulin; D010091:Oximes; D048448:Phenylcarbamates; C068836:N-acetylglucosaminono-1,5-lactone O-(phenylcarbamoyl)oxime; D013311:Streptozocin; D051057:Proto-Oncogene Proteins c-akt; D005944:Glucosamine; D000117:Acetylglucosamine