Phospholipid scramblase

In many eukaryotic plasma membranes, PS resides in the inner leaflet (Schroit and Zwaal, 1991 Zachowski, 1993). This transbilayer distribution of membrane hpids is not a static situation but a result of balance between the inward and outward translocation of phospholipids across the membranes. Recent studies showed that the transbilayer lipid asymmetry is regulated by several lipid transporter proteins, such as aminophospholipid translocase (Daleke and Lyles, 2000), ATP-binding cassette transporter family (van Helvoort et al, 1996 Klein et al, 1999), and phospholipid scramblase (Zhou et al, 1997 Zhao et al, 1998). An increment of intracellular due to cell activation, cell injury, and apoptosis affects the activities of these transporters, resulting in exposure of PS (Koopman et al, 1994 Verhoven et al, 1995) and PE (Emoto et al, 1997) on the cell surface. 

Fadeel, B., Gleiss, B., Hogstrand, K., Chandra, J., Wiedmer, T., Sims, P., Henter, J.-I, Orrenius, S., and Samah, A., 1999, Phosphatidylserine exposure during apoptosis is a cell type-specific event and does not correlate with plasma membrane phospholipid scramblase expression, Biochem. Biophys. Res. Commun. 266 504-511. 

Murakami, M., Kambe, T., Shimbara, S., Higashino, K., Hanasaki, K., Arita, H., Horiguchi, M., Arita, M., Arai, H., Inoue, K. and Kudo, I., 1999, Different functional aspects ofthe group II subfamily (Types IIA and V) and type X secretory phospholipase A(2)s in regulating arachidonic add release and prostaglandin generation. Implications of cyclooxygenase-2 induction and phospholipid scramblase-mediated cellular membrane perturbation../. Biol. Chem., 274 31435-31444. 

Zhao, J., Zhou, Q., Wiedmer, T. and Sims, P.J., 1998a, Level of expression of phospholipid scramblase regulates induced movement ofphosphatidylserine to the cell surface../. Biol. Chem. 273 6603-6606. 

---