Inositol 1,4,5-Trisphosphate Receptor: Difference between revisions
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The presence of inositol 1,4,5-trisphosphate functions to increase the cytosolic concentration of Ca<sup>2+</sup>.<ref name="functionref">PMID:10378086</ref> The InsP<sub>3</sub> is formed at the plasma membrane, diffuses into the cytosol, and binds to the InsP<sub>3</sub> receptor which is found in the membrane of intracellular Ca<sup>2+</sup> stores.<ref name="functionref"/> The release of Ca<sup>2+</sup> can propagate to other cells and can help to coordinate the functionality of organ systems.<ref name="functionref"/> Areas of the body rich in the InsP<sub>3</sub> receptor are the cerebellum and, more specifically, the endoplasmic reticulum, and even the plasma membrane and nuclei of some tissues.<ref name="functionref"/> Recent results also suggest that InsP<sub>3</sub> receptors work in intrinsic Ca<sup>2+</sup> channel activity.<ref name="functionref"/> | The presence of inositol 1,4,5-trisphosphate functions to increase the cytosolic concentration of Ca<sup>2+</sup>.<ref name="functionref">PMID:10378086</ref> The InsP<sub>3</sub> is formed at the plasma membrane, diffuses into the cytosol, and binds to the InsP<sub>3</sub> receptor which is found in the membrane of intracellular Ca<sup>2+</sup> stores.<ref name="functionref"/> The release of Ca<sup>2+</sup> can propagate to other cells and can help to coordinate the functionality of organ systems.<ref name="functionref"/> Areas of the body rich in the InsP<sub>3</sub> receptor are the cerebellum and, more specifically, the endoplasmic reticulum, and even the plasma membrane and nuclei of some tissues.<ref name="functionref"/> Recent results also suggest that InsP<sub>3</sub> receptors work in intrinsic Ca<sup>2+</sup> channel activity.<ref name="functionref"/> | ||
=== Regulation === | === Regulation of the receptor === | ||
Sequences within the receptor protein have been found to interact with accessory proteins. Additionally, there are sites for ATP binding and for phosphorylation.<ref name="functionref"/> All of these interactions would play a role in the regulation of the InsP<sub>3</sub> receptor protein. | Sequences within the receptor protein have been found to interact with accessory proteins. Additionally, there are sites for ATP binding and for phosphorylation.<ref name="functionref"/> All of these interactions would play a role in the regulation of the InsP<sub>3</sub> receptor protein. | ||
A very important property of the receptor is that it is regulated by Ca<sup>2+</sup> concentrations. Lower concentrations make the receptor more sensitive to InsP<sub>3</sub> while high concentrations can inhibit the receptor activity.<ref name="functionref"/> Also, the receptor itself can bind Ca<sup>3</sup> itself at more than one site. A Ca<sup>2+</sup> binding site within the ligand binding domain may even suggest that these Ca<sup>2+</sup> binding sites are involved in the effects Ca<sup>2+<sup> has on InsP<sub>3</sub> binding to its ligand. | A very important property of the receptor is that it is regulated by Ca<sup>2+</sup> concentrations. Lower concentrations make the receptor more sensitive to InsP<sub>3</sub> while high concentrations can inhibit the receptor activity.<ref name="functionref"/> Also, the receptor itself can bind Ca<sup>3</sup> itself at more than one site. A Ca<sup>2+</sup> binding site within the ligand binding domain may even suggest that these Ca<sup>2+</sup> binding sites are involved in the effects Ca<sup>2+</sup> has on InsP<sub>3</sub> binding to its ligand. | ||
The method of regulation by ATP on the receptor is very similar to that of Ca<sup><2+</sup> | |||