title: Structural basis for the bifunctionality of the U5 snRNP 52K protein (CD2BP2).
abstract: The bifunctional protein U5-52K is associated with the spliceosomal 20 S U5 snRNP, and it also plays a role in immune response as CD2 receptor binding protein 2 (CD2BP2). U5-52K binds to the CD2 receptor via its GYF-domain specifically recognizing a proline-rich motif on the cytoplasmic surface of the receptor. The GYF-domain is also mediating the interaction of the proteins U5-52K and U5-15K within the spliceosomal U5 snRNP. Here we report the crystal structure of the complex of GYF-domain and U5-15K protein revealing the structural basis for the bifunctionality of the U5-52K protein. The complex structure unveils novel interaction sites on both proteins, as neither the polyproline-binding site of the GYF-domain nor the common ligand-binding cleft of thioredoxin-like proteins, to which U5-15K belongs, are involved in the interaction of U5-15K and U5-52K.
authors.affiliation: Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
authors.forename: Tine K
authors.initials: TK
authors.lastname: Nielsen
authors.forename: Sunbin
authors.initials: S
authors.lastname: Liu
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lührmann
authors.forename: Ralf
authors.initials: R
authors.lastname: Ficner
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017381:Spliceosomes / Q000737:chemistry / Q000378:metabolism; D013499:Surface Properties
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C120378:CD2BP2 protein, human; D021122:Protein Subunits; D017415:Ribonucleoprotein, U5 Small Nuclear