title: Integrin clustering induces kinectin accumulation.
abstract: Integrin receptors mediate the formation of adhesion complexes and play important roles in signal transduction from the extracellular matrix. Integrin-based adhesion complexes (IAC) contain proteins that link integrins to the cytoskeleton and recruit signaling molecules, including vinculin, paxillin, focal adhesion kinase, talin and alpha-actinin. In this study, we describe a approximately 160 kDa protein that is markedly enriched at IAC induced by clustering integrins with fibronectin-coated beads. Protein sequence analysis reveals that this approximately 160 kDa protein is kinectin. Kinectin is an integral membrane protein found in endoplasmic reticulum, and it serves as a receptor for the motor protein kinesin. Fibronectin-induced IAC sequestered over half of the total cellular content of kinectin within 20 minutes. In addition, two other ER-resident proteins, RAP [low-density lipoprotein receptor-related protein (LRP) receptor-associated protein] and calreticulin, were found to be clustered at IAC, whereas kinesin was not. Our results identify a novel class of constituents of IAC.
authors.affiliation: Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4370, USA.
authors.forename: Huan
authors.initials: H
authors.lastname: Tran
authors.forename: Roumen
authors.initials: R
authors.lastname: Pankov
authors.forename: Simon D
authors.initials: SD
authors.lastname: Tran
authors.forename: Brian
authors.initials: B
authors.lastname: Hampton
authors.forename: Wilson H
authors.initials: WH
authors.lastname: Burgess
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Yamada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D002846:Chromatography, Affinity; D003599:Cytoskeleton / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008970:Molecular Weight; D021381:Protein Transport
chemical_list: D015815:Cell Adhesion Molecules; D005353:Fibronectins; D016023:Integrins; C088547:KTN1 protein, human; C511012:Ktn1 protein, mouse; D046911:Macromolecular Substances; D008565:Membrane Proteins