title: Requirement for annexin A1 in plasma membrane repair.
abstract: Ca2+ entering a cell through a torn or disrupted plasma membrane rapidly triggers a combination of homotypic and exocytotic membrane fusion events. These events serve to erect a reparative membrane patch and then anneal it to the defect site. Annexin A1 is a cytosolic protein that, when activated by micromolar Ca2+, binds to membrane phospholipids, promoting membrane aggregation and fusion. We demonstrate here that an annexin A1 function-blocking antibody, a small peptide competitor, and a dominant-negative annexin A1 mutant protein incapable of Ca2+ binding all inhibit resealing. Moreover, we show that, coincident with a resealing event, annexin A1 becomes concentrated at disruption sites. We propose that Ca2+ entering through a disruption locally induces annexin A1 binding to membranes, initiating emergency fusion events whenever and wherever required.
authors.affiliation: Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: McNeil
authors.forename: Ursula
authors.initials: U
authors.lastname: Rescher
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
authors.forename: Paul L
authors.initials: PL
authors.lastname: McNeil
mesh_terms: D017305:Annexin A1 / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes; D008846:Micromanipulation; D009154:Mutation; D021381:Protein Transport
chemical_list: D017305:Annexin A1; D002118:Calcium