KLHL10 (kelch like family member 10) is a testis-specific protein that functions as a substrate-specific adapter in CUL3-based E3 ubiquitin ligase complexes, mediating protein ubiquitination and proteasomal degradation during spermatogenesis 1. The protein contains a BTB/POZ domain and six kelch repeats, showing 98.7% amino acid identity between mouse and human orthologs 1. KLHL10 is exclusively expressed in the cytoplasm of elongating and elongated spermatids (steps 9-16) and is essential for proper spermiogenesis 1. Mechanistically, KLHL10 functions through the ubiquitin-proteasome pathway to regulate spermatid maturation, with both alleles required for male fertility 1. Haploinsufficiency causes complete infertility in male mice due to disrupted spermiogenesis, characterized by asynchronous spermatid maturation, degeneration of late spermatids, and sloughing of postmeiotic germ cells 1. The protein can form homodimers and heterodimers through its POZ domain 2. Clinically, KLHL10 is associated with spermatogenic failure, though some reported mutations may not be pathogenic 3. KLHL10 is regulated by BNC1/TAF7L transcriptional complexes and is frequently mutated in patients with idiopathic spermatogenic failure 45.