Figure 1.

Schematic signaling pathway of nutrient sensing, G−protein coupled receptors. Ligands (grey triangle) bind to nutrient−sensing receptors and coupled G−proteins to activate PLCβ2. IP3 is activated by PLCβ2 and binds to IP3 receptors to cause intracellular Ca²⁺ release (red arrow), which drives the opening of the TRPM5 cation channel and Na⁺ influx (dark yellow arrow). These changes lead to increased incretin and cytokine secretion by enteroendocrine cells. These molecules could have an influence on the gene and protein expressions, various cytokine and hormone secretion, and modified cell proliferation of target cells.