Transmembrane movements of lipids.
Membranes allow the rapid passage of unchanged lipids. Phospholipids on the other hand diffuse very slowly from one monolayer to another with a half-time of several hours. This slow spontaneous movement in a pure lipid bilayer can be selectively modulated in biological membranes by intrinsic proteins. In microsomes, and probably in bacterial membranes, non-specific phospholipid flippases allow the rapid redistribution of newly synthesized phospholipids. In eukaryotic plasma membranes, aminophospholipid translocase selectively pumps phosphatidylserine (PS) and phosphatidylethanolamine (PE) from the outer to the inner leaflet and establishes a permanent lipid asymmetry. The discovery of an aminophospholipid translocase in chromaffin granules proves that eukaryotic organelles may also contain lipid translocators.
Institut de Biologie Physico-Chimique, Paris, France.
A
A
Zachowski
P F
PF
Devaux
D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D050356:Lipid Metabolism; D010743:Phospholipids / Q000378:metabolism
D008051:Lipid Bilayers; D010743:Phospholipids