The RING-type zinc finger motif is present in a number of viral and eukaryotic proteins and is made of a conserved cysteine-rich domain that is able to bind two zinc atoms. Proteins that contain this conserved domain are generally involved in the ubiquitination pathway of protein degradation. RNF32 (RING finger protein 32), also known as HSD15 or FKSG33, is a 362 amino acid cytoplasmic protein that contains one IQ domain and two RING-type zinc fingers. Highly expressed in testis with lower expression levels in ovary tissue, RNF32 is thought to play a role in spermatogenesis, specifically contributing to the growth and maturation of round spermatids. Six isoforms of RNF32 exist due to alternative splicing events.