Cilium-specific protein required for cilia structures in Johnston's sensory organ. Plays a role in motility of cilia and flagella. Detected in the inner and outer dendritic segment and basal body. Expressed in chordotonal sense organs, Johnston's organ and sperm (at protein level). Expressed in ciliated cells. Expressed in the head and testis. Expressed in ciliated cells of the chordotonal organs, neurons of Johnston's organ and femoral chordotonal organs, olfactory sensilla on the antenna in late stage embryos and larvae. Larvae mutants are insensitive to touch and have defects in larval locomotion. Adult mutants show defects in motility and coordination and are deaf; lack antenna oscillations and mechanical amplification of stimulus-induced antennal vibrations. Mutant males can mate but are sterile because of amotile sperm; tail axonemes lacked the inner dynein arms. Belongs to the tilB family.