Mtr10p functions as a nuclear import receptor for the mRNA-binding protein Npl3p.
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.
Senger
B
B
Biochemie-Zentrum Heidelberg (BZH), Im Neuenheimer Feld 328, Germany.
Simos
G
G
Bischoff
F R
FR
Podtelejnikov
A
A
Mann
M
M
Hurt
E
E
D000595:Amino Acid Sequence; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D016296:Mutagenesis; D009685:Nuclear Envelope; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D018272:Porins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D020931:ran GTP-Binding Protein
D005656:Fungal Proteins; C080324:GSP1 protein, S cerevisiae; D008164:Luminescent Proteins; C110033:MTR10 protein, S cerevisiae; C077734:NPL3 protein, S cerevisiae; C106899:NUP85 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D018272:Porins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins; D020931:ran GTP-Binding Protein