Insight into the location and dynamics of the annexin A2 N-terminal domain during Ca-induced membrane bridging |
| |
Authors: | Jesus Ayala-Sanmartin Mallik Zibouche Françoise Illien Michel Vincent Jacques Gallay |
| |
Institution: | a INSERM U538, CHU Saint-Antoine, Paris F-75012, France b Université Pierre et Marie Curie, CHU Saint-Antoine, Paris F-75012, France c CNRS UMR8619 IBBMC, Orsay F-91405, France d Université Paris-Sud, Orsay F-91405, France |
| |
Abstract: | Annexin A2 (AnxA2) is a Ca2+- and phospholipid-binding protein involved in many cellular regulatory processes. Like other annexins, it is constituted by two domains: a conserved core, containing the Ca2+ binding sites, and a variable N-terminal segment, containing sites for interactions with other protein partners like S100A10 (p11). A wealth of data exists on the structure and dynamics of the core, but little is known about the N-terminal domain especially in the Ca2+-induced membrane-bridging process. To investigate this protein region in the monomeric AnxA2 and in the heterotetramer (AnxA2-p11)2, the reactive Cys8 residue was specifically labelled with the fluorescent probe acrylodan and the interactions with membranes were studied by steady-state and time-resolved fluorescence. In membrane junctions formed by the (AnxA2-p11)2 heterotetramer, the flexibility of the N-terminal domain increased as compared to the protein in solution. In “homotypic” membrane junctions formed by monomeric AnxA2, acrylodan moved to a more hydrophobic environment than in the protein in solution and the flexibility of the N-terminal domain also increased. In these junctions, this domain is probably not in close contact with the membrane surface, as suggested by the weak quenching of acrylodan observed with doxyl-PCs, but pairs of N-termini likely interact, as revealed by the excimer-forming probe pyrene-maleimide bound to Cys8. We present a model of monomeric AnxA2 N-terminal domain organization in “homotypic” bridged membranes in the presence of Ca2+. |
| |
Keywords: | Acrylodan 6-acryloyl-2-dimethylaminonaphthalene LUV large unilamellar vesicles MEM maximum entropy method n-doxyl PC 1-palmitoyl-2-stearoyl(n-doxyl)-sn-glycerophosphatidylcholine (n = 5 7 or 12) p11 S100A10 protein Anx annexin AnxA2acryl annexin A2 labelled with acrylodan on Cys8 AnxA2pyr annexin A2 labelled with pyrene on Cys8 (AnxA2-p11)2 heterotetramer AnxA2-p11 Pyrene-maleimide N-(1-Pyrene)maleimide PC l-α-glycerophosphatidylcholine" target="_blank">egg l-α-glycerophosphatidylcholine PS l-α-glycerophosphatidyl-l-serine" target="_blank">brain l-α-glycerophosphatidyl-l-serine PE l-α-phosphatidyl-l-ethanolamine" target="_blank">egg l-α-phosphatidyl-l-ethanolamine pCa &minus log [Ca2+] L/P lipid/protein molar ratio |
本文献已被 ScienceDirect 等数据库收录! |
|