title: Transportin-SR, a nuclear import receptor for SR proteins.
abstract: The SR proteins, a group of abundant arginine/serine (RS)-rich proteins, are essential pre-mRNA splicing factors that are localized in the nucleus. The RS domain of these proteins serves as a nuclear localization signal. We found that RS domain-bearing proteins do not utilize any of the known nuclear import receptors and identified a novel nuclear import receptor specific for SR proteins. The SR protein import receptor, termed transportin-SR (TRN-SR), binds specifically and directly to the RS domains of ASF/SF2 and SC35 as well as several other SR proteins. The nuclear transport regulator RanGTP abolishes this interaction. Recombinant TRN-SR mediates nuclear import of RS domain- bearing proteins in vitro. TRN-SR has amino acid sequence similarity to several members of the importin beta/transportin family. These findings strongly suggest that TRN-SR is a nuclear import receptor for the SR protein family.
authors.affiliation: Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania 19104-6148, USA.
authors.forename: N
authors.initials: N
authors.lastname: Kataoka
authors.forename: J L
authors.initials: JL
authors.lastname: Bachorik
authors.forename: G
authors.initials: G
authors.lastname: Dreyfuss
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism*; D001667:Binding, Competitive; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019913:Nuclear Localization Signals / Q000502:physiology*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D012261:Ribonucleoproteins; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000378:metabolism*; D000068103:Serine-Arginine Splicing Factors; D028961:beta Karyopherins; D020931:ran GTP-Binding Protein
chemical_list: D028884:Karyopherins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D010446:Peptide Fragments; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D028961:beta Karyopherins; C119888:transportin SR; C073288:SRSF2 protein, human; D000068103:Serine-Arginine Splicing Factors; D012694:Serine; D001120:Arginine; D020931:ran GTP-Binding Protein