title: The cyclophilin-like domain mediates the association of Ran-binding protein 2 with subunits of the 19 S regulatory complex of the proteasome.
abstract: The combination of the Ran-binding domain 4 and cyclophilin domains of Ran-binding protein 2 selectively associate with a subset of G protein-coupled receptors, red/green opsins, upon cis-trans prolyl isomerase-dependent and direct modification of opsin followed by association of the modified opsin isoform to Ran-binding domain 4. This effect enhances in vivo the production of functional receptor and generates an opsin isoform with no propensity to self-aggregate in vitro. We now show that another domain of Ran-binding protein 2, cyclophilin-like domain, specifically associates with the 112-kDa subunit, P112, and other subunits of the 19 S regulatory complex of the 26 S proteasome in the neuroretina. This association possibly mediates Ran-binding protein 2 limited proteolysis into a smaller and stable isoform. Also, the interaction of Ran-binding protein 2 with P112 regulatory subunit of the 26 S proteasome involves still another protein, a putative kinesin-like protein. Our results indicate that Ran-binding protein 2 is a key component of a macro-assembly complex selectively linking protein biogenesis with the proteasome pathway and, thus, with potential implications for the presentation of misfolded and ubiquitin-like modified proteins to this proteolytic machinery.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. ferreira@post.its.mcw.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Ferreira
authors.forename: C
authors.initials: C
authors.lastname: Yunfei
authors.forename: D
authors.initials: D
authors.lastname: Schick
authors.forename: R
authors.initials: R
authors.lastname: Roepman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D016350:Leucine Zippers; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D019696:Peptidylprolyl Isomerase / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C094493:ran-binding protein 2; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D019696:Peptidylprolyl Isomerase