ER membrane-bending proteins are necessary for de novo nuclear pore formation

J Cell Biol. 2009 Mar 9;184(5):659-75. doi: 10.1083/jcb.200806174.

Abstract

Nucleocytoplasmic transport occurs exclusively through nuclear pore complexes (NPCs) embedded in pores formed by inner and outer nuclear membrane fusion. The mechanism for de novo pore and NPC biogenesis remains unclear. Reticulons (RTNs) and Yop1/DP1 are conserved membrane protein families required to form and maintain the tubular endoplasmic reticulum (ER) and the postmitotic nuclear envelope. In this study, we report that members of the RTN and Yop1/DP1 families are required for nuclear pore formation. Analysis of Saccharomyces cerevisiae prp20-G282S and nup133 Delta NPC assembly mutants revealed perturbations in Rtn1-green fluorescent protein (GFP) and Yop1-GFP ER distribution and colocalization to NPC clusters. Combined deletion of RTN1 and YOP1 resulted in NPC clustering, nuclear import defects, and synthetic lethality with the additional absence of Pom34, Pom152, and Nup84 subcomplex members. We tested for a direct role in NPC biogenesis using Xenopus laevis in vitro assays and found that anti-Rtn4a antibodies specifically inhibited de novo nuclear pore formation. We hypothesize that these ER membrane-bending proteins mediate early NPC assembly steps.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Active Transport, Cell Nucleus / physiology
  • Animals
  • Endoplasmic Reticulum / metabolism*
  • Endoplasmic Reticulum / ultrastructure
  • Female
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Intracellular Membranes / metabolism*
  • Intracellular Membranes / ultrastructure
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism*
  • Mutation / genetics
  • Myelin Proteins / genetics
  • Myelin Proteins / metabolism
  • Nogo Proteins
  • Nuclear Envelope / genetics
  • Nuclear Envelope / metabolism
  • Nuclear Envelope / ultrastructure
  • Nuclear Pore / genetics
  • Nuclear Pore / metabolism*
  • Nuclear Pore / ultrastructure
  • Oocytes
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Xenopus laevis

Substances

  • Membrane Transport Proteins
  • Myelin Proteins
  • Nogo Proteins
  • Recombinant Fusion Proteins
  • Rtn1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • YOP1 protein, S cerevisiae
  • Green Fluorescent Proteins