title: Loss of plasma membrane phospholipid asymmetry requires raft integrity. Role of transient receptor potential channels and ERK pathway.
abstract: Cholesterol-rich membrane microdomains, also termed lipid rafts, are implicated in the recruitment of essential proteins for intracellular signal transduction. In nonstimulated cells, phosphatidylserine, an anionic aminophospholipid essential for the hemostatic response, is mostly sequestered in the inner leaflet of the plasma membrane. Cell stimulation by Ca(2+)-mobilizing or apoptogenic agents induces the migration of phosphatidylserine to the exoplasmic leaflet, allowing the assembly and activation of several key enzyme complexes of the coagulation cascade and phagocyte recognition of stimulated or senescent cells. We have recently proposed that store-operated Ca(2+) entry regulates externalization of phosphatidylserine at the cell surface (Kunzelmann-Marche, C., Freyssinet, J.-M., and Martinez, M. C. (2001) J. Biol. Chem. 276, 5134-5139). Here, we show that store-operated Ca(2+) entry and phosphatidylserine exposure are dramatically reduced after raft disruption by methyl-beta-cyclodextrin. In addition, transient receptor potential channel 1-specific antibody was able to significantly decrease Ca(2+)-induced redistribution of phosphatidylserine. Furthermore, store-operated Ca(2+) entry and phosphatidylserine exposure were dependent in part on the extracellular signal-regulated kinase pathway associated with rafts. Hence, raft integrity and store-operated Ca(2+) entry involving transient receptor potential channel 1 channels are essential for completion of the phosphatidylserine transmembrane redistribution process.
authors.affiliation: Institut d'Hématologie et d'Immunologie, Université Louis Pasteur, Faculté de Médecine, 4 rue Kirschleger, 67085 Strasbourg, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Kunzelmann-Marche
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Freyssinet
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Martínez
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D010718:Phosphatidylserines; D010743:Phospholipids; D002784:Cholesterol; D020928:Mitogen-Activated Protein Kinases; D013917:Thrombin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium; D009638:Norepinephrine