Involved in multiple aspects of sperm assembly including acrosome attachment, shaping of the sperm head and in the early aspects of axoneme development. Not essential for primary cilium biogenesis. Interacts (via guanylate kinase-like domain) with RIMBP3 (via coiled-coil region). Interacts (via guanylate kinase-like domain) with HOOK2. Interacts (via LRRCT domain) with KLC3. Interacts with HOOK1 and HOOK3. Localizes to the acrosome and acroplaxome in round spermatids. Localizes to the manchette during spermiogenesis. Also found in the basal body of elongating spermatids, and in primary cilia of somatic cells.