title: Two motifs essential for nuclear import of the hnRNP A1 nucleocytoplasmic shuttling sequence M9 core.
abstract: Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 regulates mRNA genesis. It shuttles between the nucleus and cytoplasm. Its shuttling signal is a 38-residue sequence M9. We studied the nuclear import and export of M9 by mutational analysis. Heterokaryon assay indicated that the 19-residue sequence SNFGPMKGGNFGGRSSGPY (M9 core) is necessary and sufficient for shuttling. Moreover, M9 core mutation revealed that in addition to the hitherto characterized N-terminal motif SNFGPMK, the C-terminal motif PY is crucial for nuclear import as well as for binding to transportin. Key residues of the motifs are conserved in the shuttling signals of hnRNP D and JKTBP.
authors.affiliation: Graduate School of Integrated Science, Yokohama City University, 22-2, Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Iijima
authors.forename: Maiko
authors.initials: M
authors.lastname: Suzuki
authors.forename: Ayako
authors.initials: A
authors.lastname: Tanabe
authors.forename: Akira
authors.initials: A
authors.lastname: Nishimura
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Yamada
mesh_terms: D021581:Active Transport, Cell Nucleus; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells; D028884:Karyopherins / Q000378:metabolism; D051379:Mice; D009154:Mutation; D010446:Peptide Fragments; D021382:Protein Sorting Signals
chemical_list: D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D028884:Karyopherins; C494045:M9 nuclear localization signal peptide; D010446:Peptide Fragments; D021382:Protein Sorting Signals