Structural and Mechanical Heterogeneity of the Erythrocyte Membrane Reveals Hallmarks of Membrane Stability
Résumé
A n essential feature of red blood cells (RBCs) relies on their capability to undergo large passive deformations throughout narrow capillaries of the micro-vasculature during their 120-days life span. Mature erythrocytes are non-nucleated, and their structural integrity depends on the particular attributes of the plasma membrane in terms of antigenic and transport activity but importantly, on its remarkable mechanical properties. 1 Many studies have unraveled the complexity hidden in the exceptional properties of the erythrocyte plasma membrane thanks to the development of isolation methods and techniques for the biochemical, structural, and functional characterization of the diverse components that integrate the erythrocyte membrane. 1À5 The RBC membrane consists of an R and β-spectrin lattice that is linked to the lipid bilayer thought membrane proteins, most of them integrating multiprotein complexes. The most abundant membrane proteins are band 3, aquaporin-1, glycophorin A and C, and the rhesus proteins, Rh and RhAG. Key for the structural integrity of the membrane are two macromolecular complexes: the an-kyrin-based complex, which is thought to work as a metabolon, and the 4.1R complex that integrates the main components of the skeleton network junctions, i.e. spectrin, actin, and protein 4.1R, together with other proteins (adducin, tropomyosin, topo-modulin, p55, and demantin) and membrane proteins such as glycophorin C (GPC) or band 3 (for a review see ref 1). It is well established, that far from being static, the RBC membrane is a metabolically regulated active structure. 5 Thus, a number of works have shown the regulatory mechanism of Ca 2þ , phosphatidylinositol 4,5-bisphos-phate (PIP 2), or protein phosphorylation on the membrane. As a result, posttranslational modifications of proteins integrating the * Address correspondence to simon.scheuring@inserm.fr.
Domaines
Biochimie, Biologie MoléculaireOrigine | Fichiers produits par l'(les) auteur(s) |
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