Required for normal structure and function of sensory cilia on amphid neurons, especially for the formation of distal ciliary structures, but is less important for normal assembly of middle and basal ciliary structures. Plays a role in the organization of axoneme microtubule bundles in sensory cilia. Required for normal structure and function of the ASER neuron that mediates attraction to NaCl. Required for normal chemotaxis to NaCl (PubMed:18245347, PubMed:26378256). Required for normal avoidance response to high osmolarity. In contrast, is not required for normal chemotaxis to isoamyl alcohol. Does not play a role in intraflagella transport (IFT) (PubMed:18245347). Promotes dauer formation in response to pheromones such as the ascarosides ascr#2, ascr#3, ascr#5, ascr#8 and icas#9 (PubMed:26976437). Detected in neuronal cell bodies, and to a lesser extent in dendrites. Detected in ASER cilia (PubMed:18245347, PubMed:26378256). Requires the intraflagella transport (IFT) machinery for normal location in cilia, but does not play a role in IFT itself (PubMed:18245347). Detected in a subset of amphid neurons that lack wing- or finger-like ciliary extensions. Likewise, detected in phasmid neurons. The TOG regions are composed of HEAT-type repeats that assemble into a solenoid structure. They mediate interaction with microtubules. Impaired structure and function of sensory cilia on amphid neurons. Strongly reduced length of the sensory cilium on the ASER neuron. Contrary to wild-type cilia that display the canonical ring of nine doublet microtubule bundles surrounding central singlet microtubules in the proximal and middle part, cilia from mutant nematodes have poorly defined microtubule organization at the cilium proximal end, and no visible microtubules at their distal ends. Belongs to the Crescerin family.