Altered O-GlcNAc modification and phosphorylation of mitochondrial proteins in myoblast cells exposed to high glucose.
Hyperglycemia induced increased posttranslational modification of proteins by O-linked-β-N-acetyl glucosamine (O-GlcNAcylation) and mitochondrial dysfunction has been independently implicated in the development of insulin resistance. It is not known whether repertoire of O-GlcNAcylated proteins includes mitochondrial proteins and their altered O-GlcNAcylation impinges on their phosphorylation mediated normal functioning thus contribute to mitochondrial dysfunction and insulin resistance. We have explored the O-GlcNAcylation of mitochondrial proteins from myoblast cells under basal (4mM) and high glucose (30mM) conditions using a combination of proteomic approaches. Furthermore, we have assessed the accompanied changes in the phosphorylation of mitochondrial proteins. We report that a number of mitochondrial proteins are O-GlcNAcylated under basal condition which is altered under high glucose condition. In addition, we report that exposure to high glucose not only changes the O-GlcNAcylation of mitochondrial proteins but also changes their phosphorylation profiles. The dynamic and complex interplay between O-GlcNAcylation and phosphorylation of mitochondrial proteins was further validated by immunoblot analysis of HSP60, prohibitin, and voltage-dependent anion channel 1 as candidate proteins. O-GlcNAcylation of mitochondrial proteins may play a role in normal functioning of mitochondria. High glucose induced changes in O-GlcNAcylation and phosphorylation of mitochondrial proteins may be associated with mitochondrial dysfunction and insulin resistance.
Gu
Yuanyuan
Y
Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
Ande
Sudharsana R
SR
Mishra
Suresh
S
D000117:Acetylglucosamine / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D002470:Cell Survival; D005947:Glucose / Q000378:metabolism*; D006943:Hyperglycemia / Q000378:metabolism*; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
D024101:Mitochondrial Proteins; D000255:Adenosine Triphosphate; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose; D000117:Acetylglucosamine