Based on limited published evidence, FIRRM regulates chromosome 1 and homologous recombination. During mitosis, FIRRM bridges PLK1 kinase and PPP1CC phosphatase activities at kinetochores to ensure faithful chromosome 1, with PLK1-mediated phosphorylation of FIRRM creating a negative feedback loop 1. In complex with FIGNL1, FIRRM negatively regulates RAD51 and DMC1 nucleoprotein filament dynamics during meiotic recombination, limiting their accumulation on chr1 and promoting efficient strand invasion and recombination intermediate processing 2, 3. FIRRM is essential for completing meiotic prophase in spermatocytes 2.