Required for correct axoneme development in spermatozoa. Important for normal development of the manchette and sperm head morphology. Essential for male fertility. Plays a role in localization of the intraflagellar transport protein IFT20 to the manchette, suggesting function as an adapter for dynein-mediated protein transport during spermatogenesis (PubMed:31278745, PubMed:31151990, PubMed:31048344). Also plays a role in bone growth where it seems to be required for normal osteoblast differentiation (By similarity). Interacts (via C-terminus) with IFT20 (PubMed:19889948). Interacts with DYNC1I2 (By similarity). Shows dynamic localization in developing spermatozoa. Localizes to the manchette in step 10-12 elongating spermatids. Detected in the basal body and neck area of step 13-14 spermatids. Localizes to the midpiece of the sperm tail in step 15-16 spermatids. During the epididymal transport of spermatozoa, expression in the sperm tail reduces and becomes concentrated at the distal part of the midpiece. Detected in the Golgi apparatus of late spermatocytes and round spermatids. Detected in the cytoplasm of Sertoli cells. The disease is caused by variants affecting the gene represented in this entry. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Truncated N-terminus.