title: Suppressor mutations suggest a surface on PAT-4 (Integrin-linked Kinase) that interacts with UNC-112 (Kindlin).
abstract: Caenorhabditis elegans striated muscle cells attach to basement membrane and transmit the force of muscle contraction through integrin adhesion complexes. The cytoplasmic tail of β-integrin (PAT-3) is associated with a conserved four-protein complex that includes UNC-112 (kindlin), PAT-4 (integrin-linked kinase), PAT-6 (α-parvin/actopaxin), and UNC-97 (PINCH). The proper localization of UNC-112 to muscle integrin adhesion sites requires PAT-4. A recent report (Qadota, H., Moerman, D. G., and Benian, G. M. (2012) A molecular mechanism for the requirement of PAT-4 (integrin-linked kinase (ILK)) for the localization of UNC-112 (kindlin) to integrin adhesion sites. J. Biol. Chem. 287, 28537-28551) suggests a possible molecular mechanism for this requirement: that UNC-112 exists in closed inactive and open active conformations, and conversion to the open active form is promoted by binding to PAT-4 (ILK). Previously, we also reported identification of a single missense mutation in UNC-112, D382V, which abolishes both binding to PAT-4 and normal localization to integrin adhesion sites in vivo. In this report, we describe isolation and characterization of PAT-4 missense mutations that permit binding with UNC-112 D382V and place nine affected residues on a homology model of PAT-4. These nine residues cluster in two regions on the surface of PAT-4, do not overlap the likely binding surface for PAT-6 (α-parvin), and therefore may reside along the interaction surface of PAT-4 for UNC-112 (kindlin). We also show that one of these PAT-4 mutations restores the ability of UNC-112 D382V to localize to integrin adhesions and participate in complex formation.
authors.affiliation: From the Department of Pathology, Emory University, Atlanta, Georgia 30322 and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Qadota
authors.affiliation: From the Department of Pathology, Emory University, Atlanta, Georgia 30322 and.
authors.forename: Yating
authors.initials: Y
authors.lastname: Luo
authors.affiliation: From the Department of Pathology, Emory University, Atlanta, Georgia 30322 and.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Matsunaga
authors.affiliation: From the Department of Pathology, Emory University, Atlanta, Georgia 30322 and.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Park
authors.affiliation: the Biomolecular Computing Resource, Emory University, Atlanta, Georgia 30322.
authors.forename: Kim M
authors.initials: KM
authors.lastname: Gernert
authors.affiliation: From the Department of Pathology, Emory University, Atlanta, Georgia 30322 and pathgb@emory.edu.
authors.forename: Guy M
authors.initials: GM
authors.lastname: Benian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D011485:Protein Binding; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D021381:Protein Transport; D013489:Suppression, Genetic; D000099200:Scaffold Protein ILK
chemical_list: D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules; D016023:Integrins; D017346:Protein Serine-Threonine Kinases; C411729:UNC-112 protein, C elegans; C466238:PAT-4 protein, C elegans; D000099200:Scaffold Protein ILK
keywords: Adhesion; C. elegans; Integrin-linked Kinase; Kindlin; Muscle; Protein Structure; Protein-Protein Interactions; Suppressor Genetics