title: Transportin-1-dependent YB-1 nuclear import.
abstract: The DNA/RNA-binding protein YB-1 (Y-box binding protein 1) performs multiple functions both in the cytoplasm and the nucleus of the cell. Generally localized to the cytoplasm, under certain conditions YB-1 is translocated to the nucleus. Here we report for the first time a transport factor that mediates YB-1 nuclear import - transportin-1. The YB-1/transportin-1 complex can be isolated from HeLa cell extract. Nuclear import of YB-1 and its truncated form YB-1 (1-219) in in vitro transport assay was diminished in the presence of a competitor substrate and ceased in the presence of transportin-1 inhibitor M9M. Inhibitors of importin β1 had no effect on YB-1 transport. Furthermore, transport of YB-1 (P201A/Y202A) and YB-1 (1-219) (P201A/Y202A) bearing inactivating mutations in the transportin-1-dependent nuclear localization signal was practically abolished. Together, these results indicate that transportin-1 mediates YB-1 nuclear translocation.
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Daria A
authors: DA
authors: Mordovkina
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Ekaterina R
authors: ER
authors: Kim
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Ilya A
authors: IA
authors: Buldakov
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Alexey V
authors: AV
authors: Sorokin
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Irina A
authors: IA
authors: Eliseeva
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia.
authors: Dmitry N
authors: DN
authors: Lyabin
authors: Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya St., 142290, Pushchino, Moscow Region, Russia. Electronic address: ovchinn@vega.protres.ru.
authors: Lev P
authors: LP
authors: Ovchinnikov
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D051840:Y-Box-Binding Protein 1 / Q000737:chemistry / Q000378:metabolism*; D028961:beta Karyopherins / Q000737:chemistry / Q000378:metabolism*
chemical_list: C108121:TNPO1 protein, human; D051840:Y-Box-Binding Protein 1; D028961:beta Karyopherins
keywords: Nuclear import; Transportin-1; YB-1