Inositol 1,4,5-trisphosphate receptor type 3 (ITPR3)

Inositol 1,4,5-trisphosphate receptor type 3 (ITPR3) is an intracellular calcium channel and receptor predominantly located on the endoplasmic reticulum membrane, functioning as a ligand-gated channel for the second messenger inositol 1,4,5-trisphosphate (IP3), thus mediating calcium release into the cytosol. ITPR3 is widely expressed in mammalian cells, with unique tissue distribution and biophysical properties distinct from other isoforms (ITPR1 and ITPR2). It plays key roles in regulating cytosolic calcium levels and downstream processes such as proliferation, apoptosis, secretion, mitochondrial function, and immune responses. ITPR3 is particularly important for taste perception (sweet, bitter, and umami), and its dysregulation has been implicated in various diseases, including autoimmunity, cancer, neurodegeneration, and immunodeficiencies. Modulators of ITPR3 are of pharmacological interest as both experimental tools and potential therapeutic agents, though clinical targeting is still largely investigational.

Other names

Inositol 1,4,5-trisphosphate-gated calcium channel ITPR3IP3R-3InsP3R3Type 3 InsP3 receptorIP3 receptor isoform 3Type 3 inositol 1,4,5-trisphosphate receptorIP3 receptorCMT1JIMD132IMD133insP3R3

Channel blockade: Inhibitors such as xestospongin B block the calcium-release function by antagonizing the IP3 binding site. Downregulation or genetic modulation (therapeutic implications under investigation). No drugs are currently approved specifically for ITPR3 as a primary therapeutic target; inhibitors are mainly research tools.