Otopetrin-2 (OTOP2)

Otopetrin-2 (OTOP2) is a member of the Otopetrin family of extracellular proton-activated proton channels and functions as an ion channel that facilitates proton (H⁺) transport across the plasma membrane[1][2][3][4]. OTOP2 forms a dimeric structure, with each subunit composed of twelve transmembrane helices organized into a unique double-barrel architecture, enabling a specialized proton-conducting pathway[1][2][3][4]. In mammals, OTOP2 is one of three related paralogs (OTOP1, OTOP2, OTOP3); while OTOP1 is known as the sour taste receptor, OTOP2's specific cellular functions and tissue expression profiles are still being elucidated[3][4]. Functional studies indicate that OTOP2 conducts protons at physiological and acidic pH, suggesting a broader role in cellular pH regulation and proton homeostasis[1][2]. However, there are currently no characterized drugs or clinical biomarkers associated with OTOP2, and its direct involvement in human disease remains under investigation[3][4].

Other names

OTOP2Otopetrin 2Proton channel OTOP2