It turns out that cholesterol is vital to sensing bitter tastes.

Humans have the ability to sense 5 different tastes – sweet, salty, sour, umami, and bitter – through specialised taste receptors located in the taste bud cells of the tongue.

When it comes to foods that leave a bitter taste in the mouth, humans have 26 different taste receptors capable of detecting more than 1,000 bitter tastants. Now, researchers have revealed exactly how we perceive those bitter tastes, in a new paper published in Nature.

Scientists solved the protein structure of one of the bitter taste receptors, TAS2R14, determining where bitter-tasting substances bind and how they activate it. They also reveal that cholesterol gives TAS2R14 a helping hand in activation, raising questions about its role with TAS2R14 in other parts of the body.

“Scientists know very little about the structural make up of sweet, bitter, and umami taste receptors,” says Dr Yoojoong Kim, a postdoctoral researcher in the University of North Carolina School of Medicine in the US, and first author of the paper.

“Using a combination of biochemical and computational methods, we now know the structure of the bitter taste receptor TAS2R14 and the mechanisms that initialises the sensation of bitter taste in our tongues.”

TAS2R14 is a G protein-coupled receptor (GPCR). When a bitter compound comes into contact with TAS2R14 it wedges itself into a specific spot on the receptor called an allosteric site. This causes the protein to change its shape and activates the attached G protein.