Inositol triphosphate receptor

Inositol triphosphate receptor (IP3R) is a membrane glycoprotein complex acting as Ca2+ channel activated by inositol triphosphate (IP3).

Distribution
It has a broad tissue distribution but is especially abundant in the cerebellum. Most of the IP3R's are found in the cell integrated into the endoplasmic reticulum.

Structure
The IP3R complex is formed of four 313 kDa subunits. There are 3 isoforms and these can form homo- or hetero-oligomers.