This ability to bind L-amino acids, specifically L-glutamine, enables the body to sense the umami, or savory, taste.

[5][8] Another interesting quality of the TAS1R1 and TAS1R2 proteins is their spontaneous activity in the absence of the extracellular domains and binding ligands.

[9] This may mean that the extracellular domain regulates function of the receptor by preventing spontaneous action as well as binding to activating ligands such as L-glutamine.

[12] Research done by creating knock-outs of common channels activated by sensory G-protein second messenger systems has also shown a connection between umami taste perception and the phosphatidylinositol (PIP2) pathway.

The nonselective cation Transient Receptor Potential channel TRPM5 has been shown to correlate with both umami and sweet taste.