Involved in radial spoke assembly. Acts upstream of or within maintenance of ciliary planar beating movement pattern. Located in cilium. Part of radial spoke head. Is expressed in lateral ventricle choroid plexus; lung epithelium; metencephalon part of 4th ventricle choroid plexus; and nasal cavity respiratory epithelium. Human ortholog(s) of this gene implicated in primary ciliary dyskinesia 11. Orthologous to human RSPH4A (radial spoke head component 4A). [provided by Alliance of Genome Resources, Apr 2022]