Involved in dynein arm assembly, is important for expression and transporting outer dynein arm (ODA) proteins from the cytoplasm to the cilia (PubMed:27353389). Acts as a crucial component in the formation and motility of spermatozoal flagella (By similarity). Interacts (via CS domain) with ZMYND10 (via C-terminus). Mainly expressed in cells with motile cilia (PubMed:27353389). Expressed in epithelial cells of the trachea, testis and ependymal cells of the cerebral ventricles (PubMed:27353389). In testis, abundant expression in late prophase of meiosis I with a dramatic decrease after the first meiotic division (at protein level) (PubMed:10775177). At the embryonic day 8.0 dpc, expressed at the node, especially in pit cells, which are located at the central region of the node and possess motile cilia. At later stages, expression is detected in the notochord at 9.0 dpc, in the hindbrain, the branchial arches and neural tube at 11.0 dpc, in the hindbrain at 12.0 dpc and in the forebrain at 13.0 dpc. Mutant mice show primary ciliary dyskinesia defects such as hydrocephalus and laterality defects and die within 5 weeks of birth. The morphology of mutant motile cilia is normal, but their motility is completely lost. The 9 + 2 arrangement of microtubules remain normal in mutants, but the outer dynein arms (ODAs) is absent from the cilia. Belongs to the tilB family.