Abstract: The present invention describes a heteromultimeric proton-gated ion channel (herein called ASIC-2S.2) with distinctive properties. Compositions and methods are provided for producing and expressing functional ASIC-2S.2 channels, composed of ASIC2A and ASIC3 subunits. The invention also provides genetically engineered expression vectors comprising the nucleic acid sequences encoding both ASIC2A and ASIC3 and host cells coexpressing both ASIC2A and ASIC3 subunits. Also provided herein are genetically engineered nucleic acids encoding chimeric proton-gated ion channels comprised of at least two different subunits, as well as expression vectors and host cells comprising said engineered nucleic acids. The invention also provides for the use of ASIC-2S.2, as well as agonists, antagonists or antibodies specifically binding ASIC-2S.2. in the diagnosis, prevention and treatment of diseases associated with expression of ASIC-2S.2.