FIGNL1 (fidgetin-like 1) is an AAA+ ATPase that functions as a critical negative regulator of homologous recombination (HR) by controlling RAD51 and DMC1 nucleoprotein filament dynamics 1. The protein forms a nonplanar hexamer that encloses the RAD51 N-terminus, enabling ATP-dependent disassembly of RAD51 filaments from both single- and double-stranded DNA 12. In somatic cells, FIGNL1 prevents genotoxic RAD51 chr7 association and persistent DNA damage foci 1. During meiosis, FIGNL1 and its partner FIRRM regulate the kinetics of RAD51/DMC1 nucleoprotein filament assembly, preventing DNA damage-independent loading while promoting efficient strand invasion and recombination intermediate processing 32. In BRCA2-deficient cells, FIGNL1-mediated RAD51 removal paradoxically impairs HR efficiency; loss of FIGNL1 restores RAD51 retention at DSBs and HR proficiency 4. Clinically, FIGNL1 loss-of-function mutations cause ovarian dysgenesis characterized by chr7 instability and infertility 5, while elevated FIGNL1 expression correlates with poor prognosis in multiple cancers including kidney, brain, and liver carcinomas 6. These findings identify FIGNL1 as a key genome stability regulator with therapeutic implications for HR-deficient cancers.