Ethanolaminephosphotransferase 1 (EPT1) is an enzyme that belongs to the CDP-Alcohol Phosphatidyltransferase Class-I Family. EPT1 is a Selenoprotein, which contains a Selenocysteine (Sec) residue at its active site. The Selenocysteine is encoded by the UGA codon that normally signals translation termination. The 3' UTR of Selenoprotein genes have a common stem-loop structure, the sec insertion sequence (SECIS), that is necessary for the recognition of UGA as a Sec codon rather than as a stop signal. EPT1 catalyzes Phosphatidylethanolamine biosynthesis from CDP-Ethanolamine. It plays a central role in the formation and maintenance of vesicular membranes. EPT1 is involved in the formation of Phosphatidylethanolamine via the 'Kennedy' pathway.