TMC4, or transmembrane channel-like 4, is a novel chloride channel with significant importance in salt taste sensation. It has been found to be involved in the reception of high-concentration NaCl, mediating the response to chloride ions in the context of salt taste [1,3]. The voltage-dependent TMC4 allows permeation of organic anions like gluconate, but with lower current amplitudes at positive potentials compared to Cl-[1].

Tmc4-deficient mice showed a significantly weaker glossopharyngeal nerve response to high-concentration of NaCl compared to wild-type littermates, indicating its role in high-concentration salt taste sensation [1]. Also, Tmc4 knockout (KO) mice had a decreased sensitivity to chloride salts such as NaCl, KCl, and NH4Cl, suggesting its involvement in the detection of chloride taste [2].

In conclusion, TMC4 is a crucial chloride channel for high-concentration salt taste sensation and chloride taste detection. The study of Tmc4-deficient and KO mouse models has provided valuable insights into its role in salt taste-related biological processes, which could potentially contribute to the development of strategies to reduce salt intake without compromising taste [1,2,3].

References:

1. Kasahara, Yoichi, Narukawa, Masataka, Ishimaru, Yoshiro, Abe, Keiko, Asakura, Tomiko. 2021. TMC4 is a novel chloride channel involved in high-concentration salt taste sensation. In The journal of physiological sciences : JPS, 71, 23. doi:10.1186/s12576-021-00807-z. https://pubmed.ncbi.nlm.nih.gov/34429071/

2. Narukawa, Masataka, Masago, Aya, Murata, Momo, Abe, Keiko, Asakura, Tomiko. . Mouse TMC4 is involved in the detection of chloride taste of salts. In Bioscience, biotechnology, and biochemistry, 88, 203-205. doi:10.1093/bbb/zbad155. https://pubmed.ncbi.nlm.nih.gov/37947260/

3. Kasahara, Yoichi, Narukawa, Masataka, Saito, Yoshikazu, Abe, Keiko, Asakura, Tomiko. 2024. The complexities of salt taste reception: insights into the role of TMC4 in chloride taste detection. In Frontiers in molecular neuroscience, 17, 1468438. doi:10.3389/fnmol.2024.1468438. https://pubmed.ncbi.nlm.nih.gov/39386048/