Article
- The EMBO Journal (1998) 17, 2196 - 2207
- doi:10.1093/emboj/17.8.2196
Mtr10p functions as a nuclear import receptor for the mRNA-binding protein Npl3p
Bruno Senger1, George Simos1, F.Ralf Bischoff2, Alexandre Podtelejnikov3, Matthias Mann3 and Ed Hurt1
- Biochemie-Zentrum Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
- Abteilung Molekulare Biologie der Mitose, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
-
EMBL, Proteins and Peptides, Meyerhofstra
e 1, D-6911 Heidelberg, Germany
Correspondence to:
Ed Hurt, E-mail: cg5@ix.urz.uni-heidelberg.de
Received 22 December 1997; Accepted 12 February 1998; Revised 12 February 1998
Abstract
MTR10, previously shown to be involved in mRNA export, was found in a synthetic lethal relationship with nucleoporin NUP85. Green fluorescent protein (GFP)-tagged Mtr10p localizes preferentially inside the nucleus, but a nuclear pore and cytoplasmic distribution is also evident. Purified Mtr10p forms a complex with Npl3p, an RNA-binding protein that shuttles in and out of the nucleus. In mtr10 mutants, nuclear uptake of Npl3p is strongly impaired at the restrictive temperature, while import of a classic nuclear localization signal (NLS)-containing protein is not. Accordingly, the NLS within Npl3p is extended and consists of the RGG box plus a short and non-repetitive C-terminal tail. Mtr10p interacts in vitro with Gsp1p-GTP, but with low affinity. Interestingly, Npl3p dissociates from Mtr10p only by incubation with Ran-GTP plus RNA. This suggests that Npl3p follows a distinct nuclear import pathway and that intranuclear release from its specific import receptor Mtr10p requires the cooperative action of both Ran-GTP and newly synthesized mRNA.
Keywords:
- importin
-homologue, - Mtr10p,
- nuclear import,
- nuclear pore complex,
- Ran mRNA export
- importin
