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Brl1p -- a novel nuclear envelope protein required for nuclear transport

Yoh-Hei Saitoh1, Kaoru Ogawa, Takeharu Nishimoto

  • 1Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.

Traffic (Copenhagen, Denmark)
|May 11, 2005
PubMed

Insights

Researchers identified a new protein, Brl1p, involved in nuclear export. Brl1p interacts with Brr6p, suggesting a collaborative role in transporting molecules out of the nucleus in yeast.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Nuclear export is crucial for cellular function, involving proteins like Xpo1p.
  • The Saccharomyces cerevisiae RCC1 homolog, srm1-1, interacts with Xpo1p.
  • Understanding novel proteins involved in nuclear transport is key to cellular regulation.

Purpose of the Study:

  • To identify novel proteins involved in nuclear export.
  • To characterize the function and interactions of a newly identified protein, Brl1p.
  • To investigate the relationship between Brl1p and Brr6p in nuclear transport.

Main Methods:

  • Isolation and characterization of a cold-sensitive Xpo1p mutant (xpo1-ok).
  • Isolation and characterization of suppressors of xpo1-ok, leading to the identification of Brl1p.
  • Generation and analysis of temperature-sensitive Brl1p mutants.
  • Two-hybrid assays to investigate protein-protein interactions.

Main Results:

  • A novel nuclear envelope integral membrane protein, Brl1p, was identified as a suppressor of xpo1-ok.
  • Brl1p is homologous to Brr6p, with conserved C-terminal domains essential for function.
  • Mutations in Brl1p caused defects in nuclear export and nuclear pore clustering, similar to brr6-1.
  • Genetic analysis and two-hybrid data confirmed a functional interaction between Brl1p and Brr6p.

Conclusions:

  • Brl1p is a novel protein essential for nuclear export in yeast.
  • Brl1p and Brr6p likely function together as a complex in nuclear export.
  • The conserved C-terminal domain is critical for the function of Brr6/Brl1 family proteins.

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