Oxidation of phosphatidylserine: a mechanism for plasma membrane phospholipid scrambling during apoptosis?
Selective oxidation of phosphatidylserine (PS) during apoptosis precedes its externalization in plasma membrane and is essential for the engulfment of apoptotic cells. To experimentally test whether PS oxidation stimulates its externalization via its effects on aminophospholipid translocase (APT) or by enhanced PS scrambling, action of oxidized PS (PSox) was studied using leukemia HL-60 cells and lymphoma Raji cells. Both PS and PSox were equally well recognized by APT. PSox did not inhibit APT. Rate of transmembrane PS diffusion was fourfold higher in cells with integrated PSox than with PS. Thus, PSox acts as a "non-enzymatic scramblase" likely contributing to PS externalization.
Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Yulia Y
YY
Tyurina
Vladimir A
VA
Tyurin
Qing
Q
Zhao
Mirjana
M
Djukic
Peter J
PJ
Quinn
Bruce R
BR
Pitt
Valerian E
VE
Kagan
D000255:Adenosine Triphosphate / Q000737:chemistry; D017209:Apoptosis; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004058:Diffusion; D005450:Fluorescamine / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010718:Phosphatidylserines / Q000737:chemistry*; D049294:Phospholipid Transfer Proteins / Q000737:chemistry; D010743:Phospholipids / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors
D008055:Lipids; D008565:Membrane Proteins; D010718:Phosphatidylserines; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; D005450:Fluorescamine; D000255:Adenosine Triphosphate; D010100:Oxygen