Topology of 1-acyl-sn-glycerol-3-phosphate acyltransferases SLC1 and ALE1 and related membrane-bound O-acyltransferases (MBOATs) of Saccharomyces cerevisiae.

In yeast, phosphatidic acid, the biosynthetic precursor for all glycerophospholipids and triacylglycerols, is made de novo by the 1-acyl-sn-glycerol-3-phosphate acyltransferases Ale1p and Slc1p. Ale1p belongs to the membrane-bound O-acyltransferase (MBOAT) family, which contains many enzymes acylating lipids but also others that acylate secretory proteins residing in the lumen of the ER. A histidine present in a very short loop between two predicted transmembrane domains is the only residue that is conserved throughout the MBOAT gene family.