Component of the nexin-dynein regulatory complex (N-DRC), a key regulator of ciliary/flagellar motility which maintains the alignment and integrity of the distal axoneme and regulates microtubule sliding in motile axonemes. Plays an important role in the assembly of the N-DRC linker (By similarity). Plays dual roles at both the primary (or non-motile) cilia to regulate hedgehog signaling and in motile cilia to coordinate cilia movement. Required for proper slow muscle development and positively regulates ciliary smoothened (SMO)-dependent Hedgehog (Hh) signaling pathway (PubMed:21659505). Required for tether cilia motility which is essential for normal otolith formation and localization in the developing inner ear (PubMed:19043402). Component of the nexin-dynein regulatory complex (N-DRC). Interacts with microtubules. Maternal transcripts are ubiquitous throughout the embryo during early development. By the 12-somite stage, expression becomes concentrated in the developing ears and this persists through the 18- to 20-somite stage. Transcripts are also present in the brain, neural tube and pronephric ducts. Morpholino knockdown results in attenuated Hedgehog (Hh) transcriptional responses and impaired early muscle development (PubMed:21659505). Morphants exhibit developmental abnormalities, abnormal ear development and defective cilia motility (PubMed:19043402). Belongs to the DRC4 family.