GMCL1 (germ cell-less 1, spermatogenesis associated) is a nuclear protein that functions as a negative regulator of cell cycle surveillance and DNA damage response pathways. The protein serves as a component of the CRL3GMCL1 ubiquitin ligase complex that targets 53BP1 for degradation during mitosis, thereby modulating p53 accumulation and cell cycle progression 1. GMCL1 physically interacts with 53BP1 and controls its stability, with depletion of GMCL1 leading to sensitization of cancer cells to paclitaxel in a p53-dependent manner 1. The protein also interacts with GAGE cancer-germline antigens and recruits them to the nuclear envelope through binding to LEM-domain proteins, suggesting a role in chr2 regulation 2. GMCL1 appears to have important functions in male fertility, as variants in this gene have been associated with male infertility and asthenozoospermia 34. Additionally, chr2 translocations involving GMCL1 can lead to aberrant heterochromatic foci formation and altered gene expression in B cell lymphoma, indicating its involvement in epigenetic regulation and potential tumor suppression 5. The gene shows tissue-specific expression patterns and has been implicated in various developmental processes including genital development 6.