Exportin-mediated nucleocytoplasmic transport maintains Pch2 homeostasis during meiosis

PLoS Genet. 2023 Nov 10;19(11):e1011026. doi: 10.1371/journal.pgen.1011026. eCollection 2023 Nov.

Abstract

The meiotic recombination checkpoint reinforces the order of events during meiotic prophase I, ensuring the accurate distribution of chromosomes to the gametes. The AAA+ ATPase Pch2 remodels the Hop1 axial protein enabling adequate levels of Hop1-T318 phosphorylation to support the ensuing checkpoint response. While these events are localized at chromosome axes, the checkpoint activating function of Pch2 relies on its cytoplasmic population. In contrast, forced nuclear accumulation of Pch2 leads to checkpoint inactivation. Here, we reveal the mechanism by which Pch2 travels from the cell nucleus to the cytoplasm to maintain Pch2 cellular homeostasis. Leptomycin B treatment provokes the nuclear accumulation of Pch2, indicating that its nucleocytoplasmic transport is mediated by the Crm1 exportin recognizing proteins containing Nuclear Export Signals (NESs). Consistently, leptomycin B leads to checkpoint inactivation and impaired Hop1 axial localization. Pch2 nucleocytoplasmic traffic is independent of its association with Zip1 and Orc1. We also identify a functional NES in the non-catalytic N-terminal domain of Pch2 that is required for its nucleocytoplasmic trafficking and proper checkpoint activity. In sum, we unveil another layer of control of Pch2 function during meiosis involving nuclear export via the exportin pathway that is crucial to maintain the critical balance of Pch2 distribution among different cellular compartments.

MeSH terms

  • Active Transport, Cell Nucleus / genetics
  • DNA-Binding Proteins / genetics
  • Homeostasis
  • Karyopherins / genetics
  • Karyopherins / metabolism
  • Meiosis / genetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins* / genetics

Substances

  • Saccharomyces cerevisiae Proteins
  • Nuclear Proteins
  • DNA-Binding Proteins
  • Karyopherins
  • Pch2 protein, S cerevisiae
  • Zip1 protein, S cerevisiae

Grants and funding

This work was supported by grant PID2021-125830NB-I00 from Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033/) and “FEDER Una manera de hacer Europa” to PASS and JAC. EH was partially supported by the grant CSI259P20 from the “Junta de Castilla y León” (co-funded by FEDER). ESD is supported by a predoctoral contract from the “Junta de Castilla y León” (co-funded by the Education Department and the European Social Fund FSE+). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.