All in Your Head: Inner Ear Linked to Sour Taste

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Someone biting into a lemon

A recent study by the USC Dornsife College of Letters, Arts and Sciences has discovered new classes of ion channels, which are present in the inner ear and responsible for balance and our taste cells that respond to sour flavors.

Since sour tastes are responsible for the perception of acidic substances, Emily Liman, USC Dornsife professor of biological sciences, predicted that sour taste cells had an ion channel that responds to or transports protons. To test this hypothesis, Liman’s lab used a molecular genetics technique called RNAseq to identify genes that specifically express sour tastes and not any other types of taste cells. Graduate student Yu-Hsiang Tu then tested the genes one-by-one until he found one that produced a proton-conducting protein.

The gene family that were identified included Otop1, Otop2 and Otop3. Per other studies, Otop1 was found necessary to the formulation of otoconia, which are calcium carbonate crystals that sense gravity and acceleration and are important for our sense of balance. It was concluded that otopetrins may be involved in our perception of sour tastes, though its function in other tissues is unknown.

"We never in a million years expected that the molecule that we were looking for in taste cells would also be found in the vestibular system," said Liman. "This highlights the power of basic or fundamental research."

To read more about the study, visit Science Daily