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.
Park
Jungeun
J
Cancer Research Institute and College of Medicine, Seoul National University, Yongon-Dong, Seoul 110-799, Korea.
Kwon
Hyejin
H
Kang
Yup
Y
Kim
Youngsoo
Y
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