Differential influence of rat liver fatty acid binding protein isoforms on phospholipid fatty acid composition: phosphatidic acid biosynthesis and phospholipid fatty acid remodeling.
The ability of two rat liver fatty acid binding protein (L-FABP) isoforms to influence microsomal phosphatidic acid biosynthesis, a key intermediate in glycerolipid formation, and phospholipid fatty acid remodeling was examined in vitro. Isoform I enhanced microsomal incorporation of [1-14C]-oleoyl-CoA into phosphatidic acid 7-fold while isoform II had no effect relative to basal. In contrast, isoform II enhanced microsomal incorporation of [1-14C]-palmitoyl-CoA into phosphatidic acid 4-fold while isoform I had no effect. These results suggest that each L-FABP isoform selectively utilized different acyl-CoAs for glycerol-3-phosphate esterification. Both isoforms stimulated phosphatidic acid formation by increasing glycerol-3-phosphate acyltransferase activity, not by increasing lysophosphatidic acid acyltransferase activity. Furthermore, the effects of L-FABP on phosphatidic acid biosynthesis could not be correlated with protection from acyl-CoA hydrolysis. L-FABP isoforms also influenced phospholipid fatty acid remodeling in a phospholipid-dependent manner. Isoform I preferentially enhanced oleate and palmitate esterification into phosphatidylethanol-amine, while isoform II stimulated esterification into phosphatidylcholine, phosphatidylserine and sphingomyelin. Taken together, these data demonstrated a unique role of each L-FABP isoform in modulating microsomally derived phospholipid fatty acid composition. (c) 1998 Elsevier Science B.V.
Jolly
C A
CA
Department of Physiology and Pharmacology, Texas A&M University, TVMC College Station, TX 77843-4466, USA.
Murphy
E J
EJ
Schroeder
F
F
D000214:Acyl Coenzyme A / Q000378:metabolism; D000217:Acyltransferases / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D018996:Myelin P2 Protein / Q000737:chemistry / Q000378:metabolism*; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010171:Palmitoyl Coenzyme A / Q000378:metabolism; D010170:Palmitoyl-CoA Hydrolase / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis*; D010743:Phospholipids / Q000737:chemistry* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000214:Acyl Coenzyme A; D002352:Carrier Proteins; C493320:Fabp1 protein, mouse; C493321:Fabp1 protein, rat; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010712:Phosphatidic Acids; D010743:Phospholipids; C017585:oleoyl-coenzyme A; D010171:Palmitoyl Coenzyme A; D000217:Acyltransferases; D005992:Glycerol-3-Phosphate O-Acyltransferase; C018764:2-acylglycerophosphate acyltransferase; D010170:Palmitoyl-CoA Hydrolase