Annexin-A5 assembled into two-dimensional arrays promotes cell membrane repair.
Bottom Line: Compared with wild-type mouse perivascular cells, AnxA5- cells exhibit a severe membrane repair defect.In contrast, an AnxA5 mutant that lacks the ability of forming 2D arrays is unable to promote membrane repair.We propose that AnxA5 participates in a previously unrecognized step of the membrane repair process: triggered by the local influx of Ca(2+), AnxA5 proteins bind to torn membrane edges and form a 2D array, which prevents wound expansion and promotes membrane resealing.
Affiliation: Molecular Imaging and NanoBioTechnology, IECB, UMR-5248 CBMN CNRS-University Bordeaux1-ENITAB, Talence F-33402, France.Show MeSH
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Mentions: Complementary experiments were performed to localize AnxA5 binding on infrared-damaged cells. Cy5-AnxA5 was found to bind exclusively to the sites of membrane injury, colocalizing with FM1-43 at initial stages after irradiation (Fig. 4). Binding of Cy5-AnxA5 occurred very rapidly after damage, in the second range, with a total absence of binding before irradiation. The fact that AnxA5 binding remains limited to damaged membrane areas at later stages indicates further that PS-exposing membranes arise from membrane injury and not from apoptosis or necrosis, in which cases AnxA5 would cover the entire cell surface (Supplementary Fig. S4).
Affiliation: Molecular Imaging and NanoBioTechnology, IECB, UMR-5248 CBMN CNRS-University Bordeaux1-ENITAB, Talence F-33402, France.