Phosphatidylserine exposure in B lymphocytes: a role for lipid packing
| Autor: | Alessandro Sardini, James I. Elliott, Giovanna Chimini, Suzel Davanture, Christopher F. Higgins, Denis R. Alexander, Joanne C. Cooper |
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| Přispěvatelé: | Centre d'Immunologie de Marseille - Luminy (CIML), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Membrane lipids
MESH: Biological Transport Immunology Cell MESH: Flow Cytometry Biology Lymphocyte Activation Phosphatidylinositols Biochemistry Flow cytometry Mice chemistry.chemical_compound MESH: Mice Inbred C57BL MESH: B-Lymphocytes medicine MESH: Phosphatidylinositols Animals MESH: Animals MESH: Lymphocyte Activation MESH: Mice Ion channel B-Lymphocytes Plasma membrane organization medicine.diagnostic_test Biological Transport Cell Biology Hematology Phosphatidylserine Flow Cytometry Lipids MESH: Lipids Cell biology Mice Inbred C57BL medicine.anatomical_structure chemistry Apoptosis [SDV.IMM]Life Sciences [q-bio]/Immunology lipids (amino acids peptides and proteins) Ex vivo |
| Zdroj: | Blood Blood, American Society of Hematology, 2006, 108 (5), pp.1611-7. ⟨10.1182/blood-2005-11-012328⟩ Blood, 2006, 108 (5), pp.1611-7. ⟨10.1182/blood-2005-11-012328⟩ |
| ISSN: | 0006-4971 1528-0020 |
| Popis: | Plasma membrane lipids are usually distributed asymmetrically, with phosphatidylserine (PS) confined to the inner leaflet. PS exposure at the outer leaflet occurs early in apoptosis, but it is also constitutive on some nonapoptotic cell populations where it plays a role in cell signaling. How PS is transported (“flopped”) to the cell surface is unknown. Contrary to previous reports that normal murine B lymphocytes lack lipid asymmetry, we show that PS is normally restricted to the inner leaflet of these cells. PS exposure on normal B cells did, however, occur spontaneously ex vivo. Consistent with the hypothesis that loss of PS asymmetry is regulated by CD45, PS is constitutively exposed on viable, CD45-deficient B cells. We show that calcium-stimulated PS exposure in B cells is strain variable, ABCA1 independent, and both preceded by and dependent on a decrease in lipid packing. This decrease in lipid packing is concomitant with cell shrinkage and consequent membrane distortion, both of which are potently inhibited by blockers of volume-regulatory K+ and Cl- ion channels. Thus, changes in plasma membrane organization precede PS translocation. The data suggest a model in which PS redistribution may occur by a translocase-independent mechanism at energetically favorable sites of membrane perturbation where lipid packing is decreased. |
| Databáze: | OpenAIRE |
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