Aging and acyl-CoA binding protein alter mitochondrial glycerol-3-phosphate acyltransferase activity.
It is well known that cellular function declines with age. Since phosphatidic acid (PtdOH) biosynthesis is central to the generation of membrane phospholipids, the hypothesis that aging decreases PtdOH biosynthesis was tested. Glycerol-3-phosphate acyltransferase (GPAT) and lysophosphatidic acid acyltransferase (LAT) activities were examined in isolated mitochondria and microsomes from young and old rat liver. The results show that mitochondrial GPAT preference for palmitoyl-CoA over oleoyl-CoA was only observed if albumin or acyl-CoA binding protein (ACBP) were present in the assay in the young rats. Furthermore, mitochondrial GPAT activity was significantly reduced in the presence of albumin and ACBP in aged mitochondria using palmitoyl-CoA as the substrate. These data show, for the first time, that mitochondrial GPAT acyl-CoA preference is due to the presence of a protein that binds acyl-CoAs, not the enzyme itself, and that aging significantly reduces mitochondrial GPAT activity.
Kannan
Latha
L
Division of Nutritional Sciences and The Institute of Cellular and Molecular Biology, The University of Texas at Austin, Gearing Room 117/A2700, Austin, TX 78712, USA.
Knudsen
Jens
J
Jolly
Christopher A
CA
D000215:Acylation; D000217:Acyltransferases / Q000378:metabolism*; D000375:Aging / Q000502:physiology*; D000818:Animals; D026261:Diazepam Binding Inhibitor / Q000494:pharmacology*; D015536:Down-Regulation; D005260:Female; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism*; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D010712:Phosphatidic Acids / Q000096:biosynthesis*; D051381:Rats; D011916:Rats, Inbred F344; D011994:Recombinant Proteins / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000494:pharmacology
D026261:Diazepam Binding Inhibitor; D010712:Phosphatidic Acids; D011994:Recombinant Proteins; D012710:Serum Albumin, Bovine; D000217:Acyltransferases; D005992:Glycerol-3-Phosphate O-Acyltransferase; C018764:2-acylglycerophosphate acyltransferase