title: Molecular Basis for the Protein Recognition Specificity of the Dynein Light Chain DYNLT1/Tctex1: CHARACTERIZATION OF THE INTERACTION WITH ACTIVIN RECEPTOR IIB.
abstract: It has been suggested that DYNLT1, a dynein light chain known to bind to various cellular and viral proteins, can function both as a molecular clamp and as a microtubule-cargo adapter. Recent data have shown that the DYNLT1 homodimer binds to two dynein intermediate chains to subsequently link cargo proteins such as the guanine nucleotide exchange factor Lfc or the small GTPases RagA and Rab3D. Although over 20 DYNLT1-interacting proteins have been reported, the exact sequence requirements that enable their association to the canonical binding groove or to the secondary site within the DYNLT1 surface are unknown. We describe herein the sequence recognition properties of the hydrophobic groove of DYNLT1 known to accommodate dynein intermediate chain. Using a pepscan approach, we have substituted each amino acid within the interacting peptide for all 20 natural amino acids and identified novel binding sequences. Our data led us to propose activin receptor IIB as a novel DYNLT1 ligand and suggest that DYNLT1 functions as a molecular dimerization engine bringing together two receptor monomers in the cytoplasmic side of the membrane. In addition, we provide evidence regarding a dual binding mode adopted by certain interacting partners such as Lfc or the parathyroid hormone receptor. Finally, we have used NMR spectroscopy to obtain the solution structure of human DYNLT1 forming a complex with dynein intermediate chain of ∼74 kDa; it is the first mammalian structure available.
authors: From the Departamento Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain and.
authors: Javier
authors: J
authors: Merino-Gracia
authors: Departamento Química Física Biológica, Instituto Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain.
authors: Héctor
authors: H
authors: Zamora-Carreras
authors: Departamento Química Física Biológica, Instituto Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain.
authors: Marta
authors: M
authors: Bruix
authors: From the Departamento Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain and nacho@bbm1.ucm.es jirodrig@quim.ucm.es.
authors: Ignacio
authors: I
authors: Rodríguez-Crespo
mesh_terms: D030301:Activin Receptors, Type II / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004398:Dyneins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D019906:Nuclear Magnetic Resonance, Biomolecular; D055503:Protein Multimerization / Q000502:physiology*; D064067:Rho Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C577402:Arhgef2 protein, mouse; C533376:DYNLT1 protein, human; C533386:Dynlt1b protein, mouse; D064067:Rho Guanine Nucleotide Exchange Factors; D030301:Activin Receptors, Type II; C425584:activin receptor type II-B; D004398:Dyneins
keywords: activin; dynein; microtubule; nuclear magnetic resonance (NMR); protein chemistry; transforming growth factor β (TGF-β); transport