Proton channel OTOP3 (OTOP3)

Proton channel OTOP3 (OTOP3) is a transmembrane ion channel belonging to the otopetrin family, responsible for highly selective transport of protons (hydrogen ions) across the cell membrane. It consists of a homodimeric structure, where each subunit has 12 transmembrane helices that form N-terminal and C-terminal domains, both likely contributing to proton conduction. OTOP3 is mainly expressed in the duodenum and small intestine, with critical roles in the formation and function of otoliths/otoconia in the inner ear—structures that are essential for sensing gravity and linear acceleration. Mutations or dysfunction in OTOP3 may contribute to vestibular system disorders such as vertigo due to disruption of these structures. The precise cellular and molecular functions, as well as potential for therapeutic targeting, remain under investigation, and no specific drugs are currently approved for or known to target OTOP3 directly.

Other names

Otopetrin-3OTOP3otopetrin 3proton channel OTOP3

If drugs were developed, likely mechanisms would be modulation or inhibition/activation of proton transport activity in the channel. For related channels, zinc can inhibit activity by blocking proton currents.