Commentary on: Direct binding of calmodulin to the cytosolic C-terminal regions of sweet/umami taste receptors.

The T1r family of receptors is essential for the detection of sweet and umami tastants, which are categorized as class C G protein-coupled receptors (GPCRs). Although these receptors share structural characteristics with other class C GPCRs, such as metabotropic glutamate receptors, they are uniquely characterized by a significantly shorter C-terminal intracellular domain, consisting of approximately 30-40 amino acid residues. Yoshida et al. recently demonstrated that the C-terminal region of mouse T1rs directly binds to calmodulin (CaM) in a Ca2+-dependent manner. This interaction highlights a previously unrecognized aspect of the intracellular signaling mechanism of T1rs, and indicates that the C-terminal region contributes to taste signal regulation, particularly through Ca2+ dependent feedback mechanisms.