LIPID TRANSMEMBRANE ASYMMETRY AND FLIP-FLOP IN BIOLOGICAL-MEMBRANES AND IN LIPID BILAYERS

During the past year, the body of evidence indicating that specific proteins are involved in the transmembrane redistribution of phospholipids in the membranes of eukaryotic cells has grown; however, no such protein has been unambiguously identified. A comparable effort has been directed towards attempting to unravel the mechanism(s) responsible for phospholipid transmembrane segregation and phospholipid scrambling. The physiological implications of the modulation of lipid asymmetry are beginning to emerge; they comprise control of enzyme activity, surface recognition and shape changes.