title: Full-Length Anion Exchanger 1 Structure and Interactions with Ankyrin-1 Determined by Zero Length Crosslinking of Erythrocyte Membranes.
abstract: Anion exchanger 1 (AE1) is a critical transporter and the primary structural scaffold for large macromolecular complexes responsible for erythrocyte membrane flexibility and integrity. We used zero-length crosslinking and mass spectrometry to probe AE1 structures and interactions in intact erythrocyte membranes. An experimentally verified full-length model of AE1 dimers was developed by combining crosslink-defined distance constraints with homology modeling. Previously unresolved cytoplasmic loops in the AE1 C-terminal domain are packed at the domain-domain interface on the cytoplasmic face of the membrane where they anchor the N-terminal domain's location and prevent it from occluding the ion channel. Crosslinks between AE1 dimers and ankyrin-1 indicate the likely topology for AE1 tetramers and suggest that ankyrin-1 wraps around AE1 tetramers, which may stabilize this oligomer state. This interaction and interactions of AE1 with other major erythrocyte membrane proteins show that protein-protein contacts are often substantially more extensive than previously reported.
authors.affiliation: The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Roland
authors.initials: R
authors.lastname: Rivera-Santiago
authors.affiliation: The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Harper
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Sira
authors.initials: S
authors.lastname: Sriswasdi
authors.affiliation: The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Hembach
authors.affiliation: The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA. Electronic address: speicher@wistar.org.
authors.forename: David W
authors.initials: DW
authors.lastname: Speicher
mesh_terms: D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017487:Ankyrins / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D000072417:Protein Domains; D055503:Protein Multimerization; D040681:Structural Homology, Protein
chemical_list: C110202:ANK1 protein, human; D001457:Anion Exchange Protein 1, Erythrocyte; D017487:Ankyrins; D003432:Cross-Linking Reagents; C454201:SLC4A1 protein, human
keywords: anion exchanger 1; ankyrin; band 3; chemical crosslinking; erythrocyte membrane; homology modeling; mass spectrometry; protein-protein interactions; red cell membranes; structural mass spectrometry