Johnson's Monday Lab Sandbox for Insulin Receptor
From Proteopedia
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==Structure== | ==Structure== | ||
| - | The insulin receptor is a | + | The insulin receptor is a '''heterotetramer''' which resides in the plasma membrane of '''insulin target cells'''. The ectodomain is made up of two alpha subunits and two beta subunits. Each alpha subunit contains two leucine rich domains and a cysteine rich domain. Each beta subunit is made up of three fibronectin type III domains. The insulin receptor extends intracellularly from the beta subunits of the ectodomain by way of a '''transmembrane''' alpha helix. The intracellular domain contains two tyrosine kinase domains. |
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===How Insulin Binds=== | ===How Insulin Binds=== | ||
The insulin receptor unit has four separate sites for the insulin molecule to bind to. There are two pairs of two identical binding sites referred to as 1 and 1' and then 2 and 2'. The insulin molecules bind to these sites mostly through [http://en.wikipedia.org/wiki/Hydrophobic_effect hydrophobic interactions]. Despite a majority of the interactions being similar, sites 1 and 1' have a higher binding affinity than sites 2 and 2' due to site one having a larger surface area (706 square angstroms) exposed for insulin to bind to compared to site 2 (394 square angstroms)<ref name="Uchikawa" />. | The insulin receptor unit has four separate sites for the insulin molecule to bind to. There are two pairs of two identical binding sites referred to as 1 and 1' and then 2 and 2'. The insulin molecules bind to these sites mostly through [http://en.wikipedia.org/wiki/Hydrophobic_effect hydrophobic interactions]. Despite a majority of the interactions being similar, sites 1 and 1' have a higher binding affinity than sites 2 and 2' due to site one having a larger surface area (706 square angstroms) exposed for insulin to bind to compared to site 2 (394 square angstroms)<ref name="Uchikawa" />. | ||
| - | It was found that at least three insulin molecules would have to | + | It was found that at least three insulin molecules would have to bind to the receptor for the receptor to take on its active “T-state” conformation <ref name="Uchikawa" />. The difference between the fully bound state with four insulins and the three insulin bound state is minimal compared to the difference between two and three insulins bound <ref name="Uchikawa" />. |
| + | ===Conformational Changes=== | ||
==Type II Diabetes== | ==Type II Diabetes== | ||
Revision as of 03:01, 23 March 2020
Insulin Receptor
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