title: Proteomic analysis of α4β1 integrin adhesion complexes reveals α-subunit-dependent protein recruitment.
abstract: Integrin adhesion receptors mediate cell-cell and cell-extracellular matrix interactions, which control cell morphology and migration, differentiation, and tissue integrity. Integrins recruit multimolecular adhesion complexes to their cytoplasmic domains, which provide structural and mechanosensitive signaling connections between the extracellular and intracellular milieux. The different functions of specific integrin heterodimers, such as α4β1 and α5β1, have been attributed to distinct signal transduction mechanisms that are initiated by selective recruitment of adhesion complex components to integrin cytoplasmic tails. Here, we report the isolation of ligand-induced adhesion complexes associated with wild-type α4β1 integrin, an activated α4β1 variant in the absence of the α cytoplasmic domain (X4C0), and a chimeric α4β1 variant with α5 leg and cytoplasmic domains (α4Pα5L), and the cataloguing of their proteomes by MS. Using hierarchical clustering and interaction network analyses, we detail the differential recruitment of proteins and highlight enrichment patterns of proteins to distinct adhesion complexes. We identify previously unreported components of integrin adhesion complexes and observe receptor-specific enrichment of molecules with previously reported links to cell migration and cell signaling processes. Furthermore, we demonstrate colocalization of MYO18A with active integrin in migrating cells. These datasets provide a resource for future studies of integrin receptor-specific signaling events.
authors.affiliation: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK.
authors.forename: Adam
authors.initials: A
authors.lastname: Byron
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Humphries
authors.forename: Sue E
authors.initials: SE
authors.lastname: Craig
authors.forename: David
authors.initials: D
authors.lastname: Knight
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Humphries
mesh_terms: D002448:Cell Adhesion; D002460:Cell Line; D006801:Humans; D039041:Integrin alpha4beta1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D009218:Myosins / Q000032:analysis / Q000378:metabolism; D060066:Protein Interaction Maps; D021122:Protein Subunits / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D015398:Signal Transduction; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis / Q000378:metabolism
chemical_list: D039041:Integrin alpha4beta1; D009218:Myosins; D021122:Protein Subunits; D019010:Vascular Cell Adhesion Molecule-1; C407152:MYO18A protein, human