Inositol triphosphate

Inositol triphosphate
Identifiers
CAS number	85166-31-0
PubChem	55310
Properties
Molecular formula	C6H15O15P3
Molar mass	420.096
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Overview

Inositol trisphosphate or inositol 1,4,5-trisphosphate (also commonly known as triphosphoinositol; abbreviated InsP₃ or IP₃), together with diacylglycerol, is a second messenger molecule used in signal transduction in biological cells. It is made by hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP₂), a phospholipid that is located in the plasma membrane, by phospholipase C.

Mechanism

IP₃ binds to and activates the InsP₃ receptor on the membrane of the sarcoplasmic reticulum (SR) opens a calcium channel, resulting in the release of Ca²⁺ into the sarcoplasm. This increase in Ca²⁺ activates the ryanodine receptor-operated channel on the SR, leading to a further increase in the Ca²⁺.

Function

Human

Its main functions are to mobilize Ca²⁺ from storage organelles and to regulate cell proliferation and other cellular reactions.

In smooth muscle cells, for example, the increase in calcium concentration cell results in contraction of the muscle cell.. For further reading of Ca²⁺-mediated functions, see functions of calcium in humans.

Fruit fly

For example, in the fruit fly Drosophila, InsP₃ is used for intracellular transduction of light recognition in eye cells.

See also

• inositol
• inositol phosphate
• myo-inositol
• inositol pentakisphosphate
• inositol hexaphosphate
• inositol triphosphate receptor

External links

• MeSH Inositol+1,4,5-Trisphosphate

References

de:Inositoltrisphosphat