Two motifs essential for nuclear import of the hnRNP A1 nucleocytoplasmic shuttling sequence M9 core.
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.
Iijima
Megumi
M
Graduate School of Integrated Science, Yokohama City University, 22-2, Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
Suzuki
Maiko
M
Tanabe
Ayako
A
Nishimura
Akira
A
Yamada
Michiyuki
M
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
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