Mechanotransduction channels have been proposed as force sensors in various physiological processes such as hearing and balance. In particular, TMC1 has been shown to constitute the pore of hair cell mechanotransduction channels, but little is known about how force is sensed by TMC channels. We have recently used the genetic tractability of C. elegans to reveal a novel molecular mechanism by which TMC channels respond to force. Our study indicates that ankyrin, which provides enough extensibility and elasticity to serve as a gating spring, acts as a long-sought intracellular tether that transmits force to TMC mechanotransduction channels via the evolutionarily conserved calcium and integrin-binding protein (CIB) in the sensory cilia of C. elegans mechanoreceptor, and possibly at the dense bodies of body wall muscles. In addition, we also establish CIB2 and CIB3 as essential components of the mechanotransduction machinery in mouse auditory and vestibular hair cells. Our research has led to important discoveries that have advanced our understanding of the molecular basis of hearing and balance.