May transfer the acyl-group from acyl-coA to the sn-1 position of glycerol-3-phosphate, an essential step in glycerolipid biosynthesis. Also transfers the acyl-group from acyl-coA to the sn-2 position of 1-acyl-sn-glycerol-3-phosphate (lysophosphatidic acid, or LPA), forming 1,2-diacyl-sn-glycerol-3-phosphate (phosphatidic acid, or PA) (By similarity). an acyl-CoA + sn-glycerol 3-phosphate = a 1-acyl-sn-glycero-3-phosphate + CoA a 1-acyl-sn-glycero-3-phosphate + an acyl-CoA = a 1,2-diacyl-sn-glycero-3-phosphate + CoA Glycerolipid metabolism; triacylglycerol biosynthesis. Phospholipid metabolism; CDP-diacylglycerol biosynthesis; CDP-diacylglycerol from sn-glycerol 3-phosphate: step 1/3. The HXXXXD motif is essential for acyltransferase activity and may constitute the binding site for the phosphate moiety of the glycerol-3-phosphate. Belongs to the 1-acyl-sn-glycerol-3-phosphate acyltransferase family. Despite its name, the human homolog of this protein appears to lack measurable glycerol-3-phosphate acyltransferase activity under some conditions (PMID:19318427).