E3 ubiquitin-protein ligase which mediates ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:19232519). Involved in chromosome segregation and cell cycle regulation (PubMed:19232519). May play a role in the acrosome reaction and fertilization (PubMed:12917430). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Interacts with CENPH. Found in the acrosomal region of elongated spermatids and mature sperm (PubMed:12917430). Colocalizes with alpha-tubulin (PubMed:19232519). Expressed in testis (PubMed:12917430). Strongly expressed in the neural tube region in 14.5 dpc embryos (PubMed:28087737). Expressed only in testicular germ cells after meiotic division. Expression was first detected at the age of 4 weeks. Belongs to the TRIM/RBCC family.