Taste receptor type 2 member 5 (TAS2R5)

Taste receptor type 2 member 5 (TAS2R5) is a **G protein-coupled receptor (GPCR)** primarily expressed in taste receptor cells of the human tongue and palate epithelia, where it functions as a bitter taste receptor mediating aversion to potentially toxic substances[1][3]. TAS2R5 is encoded by the TAS2R5 gene on chromosome 7q34 and is part of a larger family of bitter taste GPCRs referred to as TAS2Rs[1][3][4]. Each TAS2R5 protein consists of 299 amino acids arranged in seven transmembrane domains[1]. Beyond its oral sensory role, TAS2R5 is also expressed in airway smooth muscle and epithelial cells, where its activation induces bronchodilation, suggesting its potential as a therapeutic target for obstructive lung diseases such as asthma[1][2][5]. The canonical signaling involves activation of G proteins (notably Gi/α-gustducin), leading to intracellular calcium release via the PLCβ2/IP3 pathway, ultimately resulting in physiological responses such as smooth muscle relaxation or changes in ciliary beat frequency[1][5]. TAS2R5 has shown genetically linked variability in bitter taste perception, and pharmacological studies have demonstrated the potential to modulate receptor downregulation and desensitization through biased agonism, which may be relevant for drug design and chronic therapeutic applications[5]. No approved drugs target TAS2R5 clinically, but numerous synthetic and natural bitter compounds serve as agonists in research, including 1,10-phenanthroline and its analogues[2][5]. Current challenges include limited structural knowledge, low agonist affinity, and receptor desensitization with repeated stimulation[2][5]. TAS2R5 expression (along with other taste receptors) has been found to be decreased in the brains of Parkinson disease patients, but its significance in disease prognosis or therapy remains to be clarified[1].

Other names

Taste 2 receptor member 5T2R5taste receptor, type 2, member 5

Activation of G protein-coupled signaling (via Gi proteins and α-gustducin), increases intracellular calcium, induces airway smooth muscle relaxation