Inositol 1,4,5-trisphosphate (IP₃ (InsP₃))

Inositol 1,4,5-trisphosphate (IP₃) is an important small molecule second messenger produced by the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP₂) via phospholipase C following activation of G protein-coupled or tyrosine kinase receptors. IP₃ diffuses through the cytosol, binding to and activating inositol trisphosphate receptors, which are calcium channels embedded in the endoplasmic reticulum membrane. This interaction triggers the release of Ca²⁺ from ER stores, thereby facilitating numerous cellular responses including metabolism, secretion, cell proliferation, differentiation, apoptosis, and neuronal signaling. IP₃ is rapidly metabolized by specific kinases and phosphatases, tightly controlling calcium signaling. While not a therapeutic target itself, dysregulation of the IP₃ pathway is implicated in several disease states including neuropsychiatric and neurodegenerative conditions. Note: For structured entries regarding a therapeutic target, you should refer to "Inositol 1,4,5-trisphosphate receptor" (IP₃ receptor), which is the actual protein targeted by drugs and serves as the receptor for IP₃.

Other names

Inositol 1,4,5-trisphosphateIP₃InsP₃Ins3PIP3

Second messenger: Binds to the inositol trisphosphate receptor, causing Ca²⁺ release from the endoplasmic reticulum; Indirect drug modulation: Drugs target upstream or downstream enzymes/receptors, not the IP₃ molecule itself