Pch2 orchestrates the meiotic recombination checkpoint from the cytoplasm

PLoS Genet. 2021 Jul 14;17(7):e1009560. doi: 10.1371/journal.pgen.1009560. eCollection 2021 Jul.

Abstract

During meiosis, defects in critical events trigger checkpoint activation and restrict cell cycle progression. The budding yeast Pch2 AAA+ ATPase orchestrates the checkpoint response launched by synapsis deficiency; deletion of PCH2 or mutation of the ATPase catalytic sites suppress the meiotic block of the zip1Δ mutant lacking the central region of the synaptonemal complex. Pch2 action enables adequate levels of phosphorylation of the Hop1 axial component at threonine 318, which in turn promotes activation of the Mek1 effector kinase and the ensuing checkpoint response. In zip1Δ chromosomes, Pch2 is exclusively associated to the rDNA region, but this nucleolar fraction is not required for checkpoint activation, implying that another yet uncharacterized Pch2 population must be responsible for this function. Here, we have artificially redirected Pch2 to different subcellular compartments by adding ectopic Nuclear Export (NES) or Nuclear Localization (NLS) sequences, or by trapping Pch2 in an immobile extranuclear domain, and we have evaluated the effect on Hop1 chromosomal distribution and checkpoint activity. We have also deciphered the spatial and functional impact of Pch2 regulators including Orc1, Dot1 and Nup2. We conclude that the cytoplasmic pool of Pch2 is sufficient to support the meiotic recombination checkpoint involving the subsequent Hop1-Mek1 activation on chromosomes, whereas the nuclear accumulation of Pch2 has pathological consequences. We propose that cytoplasmic Pch2 provokes a conformational change in Hop1 that poises it for its chromosomal incorporation and phosphorylation. Our discoveries shed light into the intricate regulatory network controlling the accurate balance of Pch2 distribution among different cellular compartments, which is essential for proper meiotic outcomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints
  • Cell Membrane / metabolism
  • Chromosome Pairing
  • Chromosomes, Fungal
  • Cytoplasm / genetics*
  • Cytoplasm / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Histone-Lysine N-Methyltransferase / genetics
  • Histone-Lysine N-Methyltransferase / metabolism
  • Meiosis
  • Microorganisms, Genetically-Modified
  • Nuclear Pore Complex Proteins / genetics
  • Nuclear Pore Complex Proteins / metabolism
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Origin Recognition Complex / genetics
  • Recombination, Genetic*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism

Substances

  • DNA-Binding Proteins
  • HOP1 protein, S cerevisiae
  • NUP2 protein, S cerevisiae
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • ORC1 protein, S cerevisiae
  • Origin Recognition Complex
  • Pch2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Zip1 protein, S cerevisiae
  • Dot1 protein, S cerevisiae
  • Histone-Lysine N-Methyltransferase

Grants and funding

This work was supported by the grant RTI2018-099055-B-I00 from Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, EU) of Spain to PSS and JAC. EH was partially supported by the grant CSI259P20 from the “Junta de Castilla y León”. The IBFG is supported in part by an institutional grant from the “Junta de Castilla y León, Ref. CLU-2017-03 co-funded by the P.O. FEDER de Castilla y León 14-20”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.