Catalyzes a base-exchange reaction in which the polar head group of phosphatidylethanolamine (PE) or phosphatidylcholine (PC) is replaced by L-serine (, ). Catalyzes mainly the conversion of phosphatidylcholine (, ). Also converts, in vitro and to a lesser extent, phosphatidylethanolamine (, ).
Subcellular locations: Endoplasmic reticulum membrane
Highly enriched in the mitochondria-associated membrane (MAM).