Acute effects of insulin on the activity of mitochondrial GPAT1 in primary adipocytes.
The mitochondrial enzyme 1-acyl-sn-glycerol-3-phosphate acyltransferase (mtGPAT1) catalyzes a rate-limiting step in triacylglycerol and glycerophospholipid biosynthesis, which can be modulated by protein kinases in cell free analyses. We report that treatment of primary rat adipocytes with insulin acutely affects the activity of mtGPAT1 by increasing V(MAX) and K(M) for the substrates glycerol-3-phosphate and palmitoyl-CoA. Proteolytic cleavage of isolated mitochondrial membranes and mass spectrometric peptide sequencing identify in vivo phosphorylation of serine 632 and serine 639 in mtGPAT1. These phosphorylation sites correspond to casein kinase-2 consensus sequences and are highly conserved in chordate animal, but not fly, fungal or plant, mtGPAT1.
Bronnikov
Gennady E
GE
Department of Clinical and Experimental Medicine, Division of Cell Biology and Diabetes Research Centre, University of Linköping, SE58185 Linköping, Sweden.
Aboulaich
Nabila
N
Vener
Alexander V
AV
Strålfors
Peter
P
D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D047390:Casein Kinase II / Q000378:metabolism; D002384:Catalysis; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism*; D020404:Glycerophospholipids / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D013058:Mass Spectrometry; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012694:Serine / Q000737:chemistry / Q000378:metabolism; D014280:Triglycerides / Q000096:biosynthesis
D020404:Glycerophospholipids; D007328:Insulin; D014280:Triglycerides; D012694:Serine; D005992:Glycerol-3-Phosphate O-Acyltransferase; D011494:Protein Kinases; D047390:Casein Kinase II