title: RPGR ORF15 isoform co-localizes with RPGRIP1 at centrioles and basal bodies and interacts with nucleophosmin.
abstract: The ORF15 isoform of RPGR (RPGR(ORF15)) and RPGR interacting protein 1 (RPGRIP1) are mutated in a variety of retinal dystrophies but their functions are poorly understood. Here, we show that in cultured mammalian cells both RPGR(ORF15) and RPGRIP1 localize to centrioles. These localizations are resistant to the microtubule destabilizing drug nocodazole and persist throughout the cell cycle. RPGR and RPGRIP1 also co-localize at basal bodies in cells with primary cilia. The C-terminal (C2) domain of RPGR(ORF15) (ORF15(C2)) is highly conserved across 13 mammalian species, suggesting that it is a functionally important domain. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, we show that this domain interacts with a 40 kDa shuttling protein nucleophosmin (NPM). The RPGR(ORF15)-NPM interaction was confirmed by (i) yeast two-hybrid analyses; (ii) binding of both recombinant and native HeLa cell NPM to RPGR(ORF15) fusion proteins in vitro; (iii) co-immunoprecipitation of native NPM, RPGR(ORF15) and RPGRIP1 from bovine retinal extracts and of native HeLa cell NPM and transfected RPGR(ORF15) from cultured cells and (iv) co-localization of NPM and RPGR(ORF15) at metaphase centrosomes in cultured cells. NPM is a multifunctional protein chaperone that shuttles between the nucleoli and the cytoplasm and has been associated with licensing of centrosomal division. RPGR and RPGRIP1 join a growing number of centrosomal proteins involved in human disease.
authors.affiliation: MRC Human Genetics Unit, Western General Hospital, Edinburgh, UK.
authors.forename: X
authors.initials: X
authors.lastname: Shu
authors.forename: A M
authors.initials: AM
authors.lastname: Fry
authors.forename: B
authors.initials: B
authors.lastname: Tulloch
authors.forename: F D C
authors.initials: FD
authors.lastname: Manson
authors.forename: J W
authors.initials: JW
authors.lastname: Crabb
authors.forename: H
authors.initials: H
authors.lastname: Khanna
authors.forename: A J
authors.initials: AJ
authors.lastname: Faragher
authors.forename: A
authors.initials: A
authors.lastname: Lennon
authors.forename: S
authors.initials: S
authors.lastname: He
authors.forename: P
authors.initials: P
authors.lastname: Trojan
authors.forename: A
authors.initials: A
authors.lastname: Giessl
authors.forename: U
authors.initials: U
authors.lastname: Wolfrum
authors.forename: R
authors.initials: R
authors.lastname: Vervoort
authors.forename: A
authors.initials: A
authors.lastname: Swaroop
authors.forename: A F
authors.initials: AF
authors.lastname: Wright
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002417:Cattle; D002466:Cell Nucleolus / Q000378:metabolism; D002502:Centrioles / Q000378:metabolism*; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D003598:Cytoskeletal Proteins; D005091:Exons; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005982:Glutathione Transferase / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D000090243:Nucleophosmin; D016366:Open Reading Frames; D011233:Precipitin Tests; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020798:Two-Hybrid System Techniques
chemical_list: D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D020662:Guanine Nucleotide Exchange Factors; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D020033:Protein Isoforms; D011506:Proteins; C099929:RPGR protein, human; C415903:RPGRIP1 protein, human; D011993:Recombinant Fusion Proteins; D000090243:Nucleophosmin; D005982:Glutathione Transferase