Inositol 1,4,5-Trisphosphate Receptor
From Proteopedia
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<scene name='Sandbox_170/1n4k/8'>Inositol 1,4,5-trisphosphate receptor protein</scene> | <scene name='Sandbox_170/1n4k/8'>Inositol 1,4,5-trisphosphate receptor protein</scene> | ||
| - | <applet load='1n4k' size='300' frame='true' align='right' caption='Inositol 1,4,5-trisphosphate receptor' /> | + | <applet load='1n4k' size='300' frame='true' align='right' caption='Inositol 1,4,5-trisphosphate receptor. The red and orange molecule represent the ligand of the protein, inositol 1,4,5-trisphosphate' /> |
Inositol 1,4,5-trisphosphate receptor binding protein is a ubiquitous protein involved in the Ca<sup>2+</sup> signalling processes in a variety of organisms <sup>[1]</sup> | Inositol 1,4,5-trisphosphate receptor binding protein is a ubiquitous protein involved in the Ca<sup>2+</sup> signalling processes in a variety of organisms <sup>[1]</sup> | ||
| - | == Structure == | + | == Overall Structure == |
The specific type of inositol 1,4,5-trisphosphate receptor (InsP<sub>3</sub>R) protein discussed here is the mouse type one InsP<sub>3</sub>R, also called InsP<sub>3</sub>R1. This polypeptide contains three major regions: the amino terminal inositol 1,4,5-trisphosphate (InsP<sub>3</sub>) binding region, the central modulatory region, and the carboxy-terminus channel region.<sup>1</sup> The protein forms an L-shaped structure composed of two asymmetric domains perpendicular to each other.<sup>[1]</sup> The N-terminal domain is made up of 12 β-strands and 2 single-turn helices, which come together to form a barrel.<sup>[1]</sup> The C-terminal end is quite different, consisting of a bundle made of eight α-helices.<sup>[1]</sup> The interface of the two domains is lined with basic residues and forms the receptor site for InsP<sub>3</sub>.<sup>[1]</sup> The overall structure with the ligand bound can be seen here: | The specific type of inositol 1,4,5-trisphosphate receptor (InsP<sub>3</sub>R) protein discussed here is the mouse type one InsP<sub>3</sub>R, also called InsP<sub>3</sub>R1. This polypeptide contains three major regions: the amino terminal inositol 1,4,5-trisphosphate (InsP<sub>3</sub>) binding region, the central modulatory region, and the carboxy-terminus channel region.<sup>1</sup> The protein forms an L-shaped structure composed of two asymmetric domains perpendicular to each other.<sup>[1]</sup> The N-terminal domain is made up of 12 β-strands and 2 single-turn helices, which come together to form a barrel.<sup>[1]</sup> The C-terminal end is quite different, consisting of a bundle made of eight α-helices.<sup>[1]</sup> The interface of the two domains is lined with basic residues and forms the receptor site for InsP<sub>3</sub>.<sup>[1]</sup> The overall structure with the ligand bound can be seen here: | ||
[[Image:1n4k1.PNG]] | [[Image:1n4k1.PNG]] | ||
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| + | === Domain Structure === | ||
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The α-domain of InsP<sub>3</sub>R shows a high degree of homology with an element called an armidillo repeat fold found in proteins such as β-catenin and importins.<sup>[1]</sup> In β-catenin and importins, the armadillo repeat functions as a motif for protein-protein interactions.<sup>[1]</sup> Within the α-domain of mouse InsP<sub>3</sub>R1, there are two large, highly conserved surfaces.<sup>[1]</sup> Both regions are rich in aromatic residues, indicating that they may function as interaction sites for parts of the receptor or other cellular proteins.<sup>[1]</sup> A possible option for this kind of binding domain would be the InsP<sub>3</sub> binding suppressor domain present at the N-terminus which reduces the binding affinity for the InsP<sub>3</sub> ligand.<sup>[1]</sup> | The α-domain of InsP<sub>3</sub>R shows a high degree of homology with an element called an armidillo repeat fold found in proteins such as β-catenin and importins.<sup>[1]</sup> In β-catenin and importins, the armadillo repeat functions as a motif for protein-protein interactions.<sup>[1]</sup> Within the α-domain of mouse InsP<sub>3</sub>R1, there are two large, highly conserved surfaces.<sup>[1]</sup> Both regions are rich in aromatic residues, indicating that they may function as interaction sites for parts of the receptor or other cellular proteins.<sup>[1]</sup> A possible option for this kind of binding domain would be the InsP<sub>3</sub> binding suppressor domain present at the N-terminus which reduces the binding affinity for the InsP<sub>3</sub> ligand.<sup>[1]</sup> | ||
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| + | The structures of the two domains can be seen in the image below. | ||
| + | [[Image:fold regions.PNG]] | ||
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Revision as of 20:05, 17 March 2010
| Please do NOT make changes to this Sandbox until after April 23, 2010. Sandboxes 151-200 are reserved until then for use by the Chemistry 307 class at UNBC taught by Prof. Andrea Gorrell. |
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Inositol 1,4,5-trisphosphate receptor binding protein is a ubiquitous protein involved in the Ca2+ signalling processes in a variety of organisms [1]
Overall Structure
The specific type of inositol 1,4,5-trisphosphate receptor (InsP3R) protein discussed here is the mouse type one InsP3R, also called InsP3R1. This polypeptide contains three major regions: the amino terminal inositol 1,4,5-trisphosphate (InsP3) binding region, the central modulatory region, and the carboxy-terminus channel region.1 The protein forms an L-shaped structure composed of two asymmetric domains perpendicular to each other.[1] The N-terminal domain is made up of 12 β-strands and 2 single-turn helices, which come together to form a barrel.[1] The C-terminal end is quite different, consisting of a bundle made of eight α-helices.[1] The interface of the two domains is lined with basic residues and forms the receptor site for InsP3.[1] The overall structure with the ligand bound can be seen here:
Domain Structure
The protein fold of the β-domain can also be called the β-trefoil. This element is present in other proteins as well, including fibroblast growth factors and mannose receptors.[1] In the case of the InsP3R β-trefoil, the structure was found to be very similar to the β-trefoil of the mannose receptor. In the β-domain of InsP3R1, three of six two-stranded hairpins come together to form a barrel and the other three form a triangular cap for the barrel.[1]
The α-domain of InsP3R shows a high degree of homology with an element called an armidillo repeat fold found in proteins such as β-catenin and importins.[1] In β-catenin and importins, the armadillo repeat functions as a motif for protein-protein interactions.[1] Within the α-domain of mouse InsP3R1, there are two large, highly conserved surfaces.[1] Both regions are rich in aromatic residues, indicating that they may function as interaction sites for parts of the receptor or other cellular proteins.[1] A possible option for this kind of binding domain would be the InsP3 binding suppressor domain present at the N-terminus which reduces the binding affinity for the InsP3 ligand.[1]
The structures of the two domains can be seen in the image below. Image:Fold regions.PNG
Proteopedia Page Contributors and Editors (what is this?)
Shannon King, Alexander Berchansky, Michal Harel, Ann Taylor, David Canner, Andrea Gorrell, Jaclyn Gordon
