Plasma Membrane Phospholipid Asymmetry
2006; Springer Science+Business Media; Linguagem: Inglês
10.1007/0-306-47931-1_3
Autores Tópico(s)Sphingolipid Metabolism and Signaling
ResumoConclusionsThe maintenance of an asymmetric distribution of phospholipids across the plasma membrane with choline phospholipids predominating on the external surface and amino phospholipids confined to the cytoplasmic leaflet of the membrane has now been well established. The participation of aminophospholipid translocases in this process has been clearly demonstrated and the translocases themselves have been characterized.One of the more significant events associated with dissipation of phospholipid asymmetry is the appearance of phosphatidylserine on the surface of the cell. This provides a clear signal for altering the hemeostatic balance since several procoagulant and anticoagulant reactions depend on interfaces containing phosphatidyserine. Furthermore, the appearance of phosphatidylserine on the cell surface appears to be the primary reaction mediating recognition and clearance of apoptotic cells by macrophages so as to prevent release of inflammatory cell contents associated with lysis.The control of the processes of phospholipid translocation and scrambling by cytoplasmic calcium concentration is known to be one factor in regulating the appearance of phosphatidylserine on the cell surface. There is now evidence that other factors are involved in modulating membrane phospholipid distribution and for preserving phospholipid homeostasis. Current research is directed to clarify the role of these agents and to establish any connections with the initiation of apoptosis.
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