Mtr10p functions as a nuclear import receptor for the mRNA-binding protein Npl3p

EMBO J. 1998 Apr 15;17(8):2196-207. doi: 10.1093/emboj/17.8.2196.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Biological Transport
  • Cell Nucleus / metabolism
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • GTP-Binding Proteins / metabolism
  • Green Fluorescent Proteins
  • Guanosine Triphosphate / metabolism
  • Humans
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Molecular Sequence Data
  • Monomeric GTP-Binding Proteins*
  • Mutagenesis
  • Nuclear Envelope
  • Nuclear Pore Complex Proteins*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Nucleocytoplasmic Transport Proteins*
  • Porins / genetics
  • Porins / metabolism
  • RNA, Messenger
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Ribonucleoproteins / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Temperature
  • ran GTP-Binding Protein

Substances

  • Fungal Proteins
  • GSP1 protein, S cerevisiae
  • Luminescent Proteins
  • MTR10 protein, S cerevisiae
  • NPL3 protein, S cerevisiae
  • NUP85 protein, S cerevisiae
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • Nucleocytoplasmic Transport Proteins
  • Porins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • Saccharomyces cerevisiae Proteins
  • Green Fluorescent Proteins
  • Guanosine Triphosphate
  • GTP-Binding Proteins
  • Monomeric GTP-Binding Proteins
  • ran GTP-Binding Protein