Dual substrate-specific glycerol-3-phosphate/dihydroxyacetone phosphate sn-1 acyltransferase, catalyzing the first and committed reaction in the de novo synthesis of glycerophospholipids and triacylglycerols (TAGs). Can use both Gly-3-P and dihydroxyacetone phosphate with similar efficiencies and has a broad fatty acyl-CoA specificity profile. Transfers a fatty acid from fatty acyl-CoA to the sn-1 position of glycerol-3-phosphate to produce lysophosphatidic acid (LysoPA). These lipids not only are precursors of glycerolipids, but also are dynamic components of signal transduction systems that control cell physiology. an acyl-CoA + sn-glycerol 3-phosphate = a 1-acyl-sn-glycero-3-phosphate + CoA an acyl-CoA + dihydroxyacetone phosphate = a 1-acylglycerone 3-phosphate + CoA hexadecanoyl-CoA + sn-glycerol 3-phosphate = 1-hexadecanoyl-sn-glycero-3-phosphate + CoA (9Z)-hexadecenoyl-CoA + sn-glycerol 3-phosphate = 1-(9Z-hexadecenoyl)-sn-glycero-3-phosphate + CoA octadecanoyl-CoA + sn-glycerol 3-phosphate = 1-octadecanoyl-sn-glycero-3-phosphate + CoA (9Z)-octadecenoyl-CoA + sn-glycerol 3-phosphate = 1-(9Z-octadecenoyl)-sn-glycero-3-phosphate + CoA Phospholipid metabolism; CDP-diacylglycerol biosynthesis; CDP-diacylglycerol from sn-glycerol 3-phosphate: step 1/3. Localizes to both perinuclear and cortical endoplasmic reticulum. Phosphorylatied at a conserved motif involving Ser-664, Ser-668 and Ser-671. This phosphorylation plays a critical role for efficient TAG mobilization. Phosphorylation deficiency at this motif increases the enzyme activity and consequently induces de novo formation of phosphatidic acid. Present with 3100 molecules/cell in log phase SD medium. Belongs to the GPAT/DAPAT family.