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IP3 receptors C

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).


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The inositol 1,4,5-trisphosphate receptors (IP3R) are ligand-gated Ca2+-release channels on intracellular Ca2+ store sites (such as the endoplasmic reticulum). They are responsible for the mobilization of intracellular Ca2+ stores and play an important role in intracellular Ca2+ signalling in a wide variety of cell types. Three different gene products (types I-III) have been isolated, which assemble as large tetrameric structures. IP3Rs are closely associated with certain proteins: calmodulin (CALM2, CALM3, CALM1, P62158) and FKBP (and calcineurin via FKBP). They are phosphorylated by PKA, PKC, PKG and CaMKII.

Channels and Subunits

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Targets of relevance to immunopharmacology are highlighted in blue

IP3R1 C Show summary »

IP3R2 C Show summary »

Target Id 744
Nomenclature IP3R2
Previous and unofficial names INSP3R2 | IP3R2 | inositol 1,4,5-triphosphate receptor 2 | IP3 receptor | Itpr5 | inositol 1
Genes ITPR2 (Hs), Itpr2 (Mm), Itpr2 (Rn)
Ensembl ID ENSG00000123104 (Hs), ENSMUSG00000030287 (Mm), ENSRNOG00000001804 (Rn)
UniProtKB AC Q14571 (Hs), Q9Z329 (Mm), P29995 (Rn)
Endogenous activators
cytosolic Ca2+ (nM range)
IP3 (endogenous; nM - μM range)
adenophostin A (pharmacological; nM range)
inositol 2,4,5-trisphosphate (pharmacological; also activated by other InsP3 analogues)
decavanadate (μM range)
Functional characteristics Ca2+: single-channel conductance
~70 pS (50 mM Ca2+)
~390 pS (220 mM Cs+)

IP3R3 C Show summary »


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Further reading

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How to cite this family page

Database page citation:

IP3 receptors. Accessed on 20/02/2024. IUPHAR/BPS Guide to PHARMACOLOGY,

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Mathie AA, Peters JA, Veale EL, Striessnig J, Kelly E, Armstrong JF, Faccenda E, Harding SD, Davies JA et al. (2023) The Concise Guide to PHARMACOLOGY 2023/24: Ion channels. Br J Pharmacol. 180 Suppl 2:S145-S222.