Generation of membrane diversity by lysophospholipid acyltransferases.

Glycerophospholipids are main components of cellular membranes and have numerous structural and functional roles to regulate cellular functions. Polyunsaturated fatty acids, such as arachidonic acid and eicosapentaenoic acid, are mainly located at the sn-2, but not the sn-1 position of glycerophospholipids in an asymmetrical manner and the fatty acid compositions at both the sn-1 and sn-2 positions differ in various cell types and tissues. Asymmetry and diversity of membrane glycerophospholipids are generated in the remodelling pathway (Lands' cycle), which are conducted by the concerted actions of phospholipases A2 (PLA2s) and lysophospholipid acyltransferases (LPLATs). The Lands' cycle was first reported in the 1950s. While PLA2s have been well characterized, little is known about the LPLATs. Recently, several laboratories, including ours, isolated LPLATs that function in the Lands' cycle from the 1-acylglycerol-3-phosphate O-acyltransferase family and the membrane bound O-acyltransferases family. In this review, we summarize recent studies on cloning and characterization of LPLATs that contribute to membrane asymmetry and diversity.