USP26

USP26 is a peptidase enzyme. The USP26 gene is an X-linked gene exclusively expressed in the testis and it codes for the ubiquitin-specific protease 26.^[1] The USP26 gene is found at Xq26.2 on the X-chromosome as a single exon. The enzyme that this gene encodes comprises 913 amino acid residues and it is 104 kilodalton in size, which is transcribed from a sequence of 2794 nucleotide base-pairs on the X-chromosome.^[2] The USP26 enzyme is a deubiquitinating enzyme that places a very significant role in the regulation of protein turnover during spermatogenesis. It is a testis-specific enzyme that is solely express in spermatogonia and can prevent the degradation of ubiquitinated USP26 substrates.^[3]

Recent research has suggested that defects in USP26 may be involved in some cases of male infertility,^[1][4] specifically Sertoli cell-only syndrome, and an absence of sperm in the ejaculate (azoospermia).^[5]