Yeast Rad55-Rad57-SHU paralog complex dynamically promotes Rad51 filament formation.

Yeast Rad55-Rad57-SHU complex promotes Rad51 filament formation through a dual-nucleotide regulatory mechanism.

• Why it matters: Understanding how Rad51 paralogs facilitate homologous recombination is crucial because they act as tumor suppressors in humans, and defects in this process can compromise genome stability.
• What they did: The study used cryo-electron microscopy to capture six distinct states of the Saccharomyces cerevisiae Rad55-Rad57-SHU complex, revealing how it recruits Rad51 to single-stranded DNA and the role of nucleotide binding in regulation.
• The result: Findings show that a structural ADP stabilizes the complex while ATPase activity at the Rad57-Rad51 interface promotes complex release, providing a structural blueprint for Rad51 paralog function across eukaryotes.