This domain can be found in coiled-coil domain-containing protein 66 (CCDC). It is approximately 160 amino acids in length. CCDC66 protein is detected mainly in the inner segments of photoreceptors in many vertebrates including mice and humans. It has been found in dogs, that a mutation in the CCDC66 gene causes generalized progressive retinal atrophy (gPRA). This shows that the protein encoded for by this gene is vital for healthy vision and guards against photoreceptor cell degeneration. The structure of CCDC66 proteins includes a heptad repeat pattern which contains at least one coiled-coil domain. There are at least two or more α-helices which form a cable-like structure [].
CCDC66 localizes to the centrosome and the centriolar satellites []. It interacts with CEP290 and functions in cilium formation and trafficking. It has also been shown to bind to microtubules in vitro and in vivo []. Mutations of the CCD66 gene in dogs cause progressive retinal atrophy []. Homologues are found only in metazoa.
