Phosphatidic acid and lysophosphatidic acid are phospholipids involved in lipid biosynthesis and signal transduction. LPAAT-epsilon (lysophosphatidic acid acyltransferase epsilon, also designated 1-AGP acyltransferase 5 (AGPAT5)) catalyzes the synthesis of phosphatidic acid from lysophosphatidic acid. LPAAT-epsilon is a membrane-bound protein belonging to the LPAAT family. Members of the LPAAT family have a well-known role in lipid biosynthesis and they may also play a role in tumor progression. LPAAT-epsilon is expressed in a tissue-specific manner in prostate and testis. LPAAT-epsilon is most closely related to AGPAT8, which is highly expressed in heart.