May interact with TEKT2. In caput spermatozoa, localized in the middle piece, but predominantly concentrated at the mitochondrial sheath of the flagella and to a lesser extent with outer dense fibers (ODF). Colocalized with TEKT2 at the perinuclear region (By similarity). Detected in spermatozoa (at protein level). Predominantly expressed in testis and in spermatozoa from the caput and corpus epididymis. Increased after 3 weeks of postnatal development. Belongs to the CCDC172 family.