title: Heterogeneity and timing of translocation and membrane-mediated assembly of different annexins.
abstract: Many cell types, including neurons and epithelial cells, express a variety of annexins. Although the overall function has only been partially unravelled, a dominant feature is the formation of two-dimensional assemblies under the plasma membrane in a calcium-dependent manner. Here we show that fluorescently tagged annexins A1, A2, A4, A5, and A6 translocate and assemble at the plasma membrane and the nuclear envelope, except annexin A2, which only attaches to the plasma membrane. All annexins have different response times to elevated calcium levels as was shown by the translocation of co-expressed proteins. Fluorescence recovery after photobleaching revealed the static nature of all annexin assemblies. Analysis of the assemblies by Foerster resonance energy transfer (FRET) using acceptor bleaching demonstrated mostly annexin-specific self-assembly. Heterogeneous assembly formation was shown between annexins A5 and A1, and A5 and A2. The formation of homo- and heterogeneous annexin assemblies may play an important role when high increases in calcium occur, such as after disruption of the plasma membrane.
authors.affiliation: Gene Expression Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Skrahina
authors.forename: Alen
authors.initials: A
authors.lastname: Piljić
authors.forename: Carsten
authors.initials: C
authors.lastname: Schultz
mesh_terms: D017305:Annexin A1 / Q000235:genetics / Q000378:metabolism; D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism; D017314:Annexin A4 / Q000235:genetics / Q000378:metabolism; D017304:Annexin A5 / Q000235:genetics / Q000378:metabolism; D017317:Annexin A6 / Q000235:genetics / Q000378:metabolism; D017302:Annexins / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D046912:Multiprotein Complexes; D038761:Photobleaching; D021381:Protein Transport; D014162:Transfection
chemical_list: C472822:ANXA2 protein, human; D017305:Annexin A1; D017306:Annexin A2; D017314:Annexin A4; D017304:Annexin A5; D017317:Annexin A6; D017302:Annexins; D046912:Multiprotein Complexes