CCDC39 is an axonemal protein with coiled-coil domains required for assembly of inner dynein arms and the dynein regulatory complex, a key regulator of motor activity in cilia []. Mutations in CCDC39 are a cause of primary ciliary dyskinesia, a disorder caused by cilia and sperm dysmotility [].
Coiled-coil domain containing protein 40 (CCDC40) plays an evolutionary conserved role in the assembly of motile cilia and establishment of the left-right axis [, ]. CCDC40 may serve as a part of the axoneme structural scaffold. It has been shown to be required for axonemal recruitment of CCDC39 []. CCDC40 mutation is a cause of primary ciliary dyskinesia [].
