Glucose deprivation-induced increase in protein O-GlcNAcylation in cardiomyocytes is calcium-dependent.
The posttranslational modification of nuclear and cytosolic proteins by O-linked β-N-acetylglucosamine (O-GlcNAc) has been shown to play an important role in cellular response to stress. Although increases in O-GlcNAc levels have typically been thought to be substrate-driven, studies in several transformed cell lines reported that glucose deprivation increased O-GlcNAc levels by a number of different mechanisms. A major goal of this study therefore was to determine whether in primary cells, such as neonatal cardiomyocytes, glucose deprivation increases O-GlcNAc levels and if so by what mechanism. Glucose deprivation significantly increased cardiomyocyte O-GlcNAc levels in a time-dependent manner and was associated with decreased O-GlcNAcase (OGA) but not O-GlcNAc transferase (OGT) protein. This response was unaffected by either the addition of pyruvate as an alternative energy source or by the p38 MAPK inhibitor SB203580. However, the response to glucose deprivation was blocked completely by glucosamine, but not by inhibition of OGA with 2-acetamido-2-deoxy-d-glucopyranosylidene)amino-N-phenylcarbamate. Interestingly, the CaMKII inhibitor KN93 also significantly reduced the response to glucose deprivation. Lowering extracellular Ca(2+) with EGTA or blocking store operated Ca(2+) entry with SKF96365 also attenuated the glucose deprivation-induced increase in O-GlcNAc. In C2C12 and HEK293 cells both glucose deprivation and heat shock increased O-GlcNAc levels, and CaMKII inhibitor KN93 attenuated the response to both stresses. These results suggest that increased intracellular calcium and subsequent activation of CaMKII play a key role in regulating the stress-induced increase in cellular O-GlcNAc levels.
Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA.
Luyun
L
Zou
Xiaoyuan
X
Zhu-Mauldin
Richard B
RB
Marchase
Andrew J
AJ
Paterson
Jian
J
Liu
Qinglin
Q
Yang
John C
JC
Chatham
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors; D005947:Glucose / Q000378:metabolism*; D006031:Glycosylation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D009124:Muscle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
D004791:Enzyme Inhibitors; D009124:Muscle Proteins; D017351:N-Acetylglucosaminyltransferases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; D002118:Calcium