The video illustrates how the proton channel OTOP1 lets sour taste receptor cells in the mouth respond to acids. [Credit: Nancy R. Gough, BioSerendipity, LLC]
Read about this research:
N. R. Gough, Genetically Engineered Mice Reveal Mechanism of Sour Taste. BioSerendipity (15 November 2019) https://www.bioserendipity.com/genetically-engineered-mice-reveal-mechanism-of-sour-taste/
