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: Strikingly, unlike native AnxA5, mtT-AnxA5 was unable to promote membrane repair (Table 1). We considered the possibility that the difference in behaviour between mtT-AnxA5 and native AnxA5 could be due to a difference in their membrane-binding properties, and measured their binding to PS-containing membranes. Native AnxA5 and mutant mtT-AnxA5 present undistinguishable binding characteristics to model membranes (Fig. 6a). This result is in agreement with previous indication that AnxA5–AnxA5 intermolecular interactions, in other words the formation of AnxA5 2D self-assemblies, does not contribute to membrane-binding affinity44. In addition, Cy5-mtT-AnxA5 bound to damaged membrane areas of irradiated wt-PV cells, similar to native AnxA5 (Fig. 6b). We conclude therefore that AnxA5 promotes membrane repair through the formation of ordered 2D arrays at the sites of membrane rupture.
Affiliation: Molecular Imaging and NanoBioTechnology, IECB, UMR-5248 CBMN CNRS-University Bordeaux1-ENITAB, Talence F-33402, France.