title: The S100A10-annexin A2 complex provides a novel asymmetric platform for membrane repair.
abstract: Membrane repair is mediated by multiprotein complexes, such as that formed between the dimeric EF-hand protein S100A10, the calcium- and phospholipid-binding protein annexin A2, the enlargeosome protein AHNAK, and members of the transmembrane ferlin family. Although interactions between these proteins have been shown, little is known about their structural arrangement and mechanisms of formation. In this work, we used a non-covalent complex between S100A10 and the N terminus of annexin A2 (residues 1-15) and a designed hybrid protein (A10A2), where S100A10 is linked in tandem to the N-terminal region of annexin A2, to explore the binding region, stoichiometry, and affinity with a synthetic peptide from the C terminus of AHNAK. Using multiple biophysical methods, we identified a novel asymmetric arrangement between a single AHNAK peptide and the A10A2 dimer. The AHNAK peptide was shown to require the annexin A2 N terminus, indicating that the AHNAK binding site comprises regions on both S100A10 and annexin proteins. NMR spectroscopy was used to show that the AHNAK binding surface comprised residues from helix IV in S100A10 and the C-terminal portion from the annexin A2 peptide. This novel surface maps to the exposed side of helices IV and IV' of the S100 dimeric structure, a region not identified in any previous S100 target protein structures. The results provide the first structural details of the ternary S100A10 protein complex required for membrane repair.
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada.
authors.forename: Atoosa
authors.initials: A
authors.lastname: Rezvanpour
authors.forename: Liliana
authors.initials: L
authors.lastname: Santamaria-Kisiel
authors.forename: Gary S
authors.initials: GS
authors.lastname: Shaw
mesh_terms: D000818:Animals; D017306:Annexin A2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011817:Rabbits; D009418:S100 Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D000099248:S100 Calcium Binding Protein A10
chemical_list: D017306:Annexin A2; D046912:Multiprotein Complexes; D010455:Peptides; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10