TAS2R43 is a gustducin-coupled bitter taste receptor with roles extending beyond oral taste perception to gastrointestinal and immune functions. Primary function: TAS2R43 detects bitter compounds including saccharin, acesulfame K, aloin, denatonium, and coffee constituents like mozambioside and cafestol 1, signaling through PLCB2 and TRPM5 calcium channels [UniProt]. Mechanism: In intestinal epithelial cells, TAS2R43 activation triggers antimicrobial peptide release (α-defensin 5, REG3A) and induces NRF2-mediated nutrient stress responses affecting metabolic regulators like GDF15 2. In gastric parietal cells, TAS2R43 stimulates proton secretion and serotonin release, contributing to satiety signaling 3. Disease relevance: TAS2R43 polymorphisms significantly influence susceptibility to Balkan Endemic Nephropathy, a kidney disease from aristolochic acid exposure, with functional variants paradoxically increasing vulnerability 4. Genetic variations in TAS2R43 affect intestinal immune responses in obesity 2 and sensitivity to bitter compound perception 5. Clinical significance: TAS2R43 represents a therapeutic target for immune-related diseases and metabolic disorders, with polymorphisms serving as genetic markers for predicting treatment responses 2. Copy number variations in TAS2R43 correlate with gut microbiota composition 6, indicating broader metabolic implications.