Conserved phosphorylation motif in yeast Pch2 protein identified as critical regulator of meiotic chromosome dynamics

The Pch2 protein is a conserved AAA+ ATPase required for correct chromosome dynamics during meiosis. It acts by remodelling the HORMA-domain protein Hop1, promoting conformational changes essential for chromosome axis organisation, checkpoint signalling, and the control of meiotic recombination. Despite its importance, the molecular mechanisms that regulate Pch2 activity and localisation remain incompletely understood.

A preprint posted to bioRxiv in June 2026 reports that threonine 428 (T428), located within a conserved threonine-glutamine (TQ) putative phosphorylation motif, is a critical regulatory residue of Pch2 in Saccharomyces cerevisiae. Experiments in zip1-deletion backgrounds — where Pch2 localisation is altered — demonstrated that T428 mutations affect both the protein's chromosomal distribution and its meiotic function. The TQ motif is a recognition sequence for checkpoint kinases, suggesting a link between DNA damage or recombination checkpoint signalling and Pch2 regulation.

The findings contribute to the molecular understanding of meiotic recombination control, which is relevant to research on meiotic drive, de novo mutation, and reproductive genetics more broadly. The work is most relevant to researchers in meiotic biology, yeast genetics, and molecular genetics. This is a preprint and has not yet been peer-reviewed.