Influence of erythrocyte shape on the rate of Ca2+-induced scrambling of phosphatidylserine.
Membrane-perturbing agents that cause transformation of biconcave erythrocytes into echinocytes or stomatocytes were used to investigate the influence of erythrocyte shape on the rate of Ca(2+)-induced scrambling of phospholipids. Erythrocytes were treated with a variety of lipid-soluble compounds to induce these shape changes, followed by incubation with calcium and ionomycin to activate lipid scramblase. Prothrombinase activity of the cells was used to monitor the rate of surface exposure of phosphatidylserine, which is taken as a measure of scramblase activity. Echinocytes show an enhanced rate of scrambling, whereas stomatocytes show a reduced rate, relative to normocytes. This phenomenon appears to correlate with enhanced and diminished micro-exovesicle shedding from echinocytes and stomatocytes, respectively. It is concluded that the rate of calcium-induced phosphatidylserine exposure (rate of lipid scrambling) in erythrocytes depends for a considerable part on the cells' ability to form microvesicles.
Department of Biochemistry, Cardiovascular Research Institute Maastricht, The Netherlands. jef.wolfs@pandora.be
Jef L N
JL
Wolfs
Paul
P
Comfurius
Edouard M
EM
Bevers
Robert F A
RF
Zwaal
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives* / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D002746:Chlorpromazine / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology; D003992:Dibucaine / Q000494:pharmacology; D004912:Erythrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D010713:Phosphatidylcholines / Q000494:pharmacology; D010718:Phosphatidylserines / Q000378:metabolism*; D049294:Phospholipid Transfer Proteins; D022142:Secretory Vesicles / Q000378:metabolism; D013925:Thromboplastin / Q000187:drug effects / Q000378:metabolism
C078632:1-acyl-2-(12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl)phosphatidylcholine; D002352:Carrier Proteins; D003902:Detergents; D007476:Ionophores; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D049294:Phospholipid Transfer Proteins; C015132:1,2-didecanoylphosphatidylcholine; D013925:Thromboplastin; D008012:Lidocaine; D009327:4-Chloro-7-nitrobenzofurazan; D003992:Dibucaine; D002118:Calcium; D002746:Chlorpromazine