Sandbox Reserved 1627: Difference between revisions

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The beta subunit spans from the extracellular domain across the transmembrane region and into the intracellular portion of the insulin receptor. The beta subunit is composed of part of [http://en.wikipedia.org/wiki/Fibronectin fibronectin] domain III-2 and all of Fibronectin domain III-3. The beta subunit's FnIII-3 domain has links through the transmembrane region into the intracellular part of the membrane.[http://en.wikipedia.org/wiki/Transmission_electron_cryomicroscopy Cryo-EM] results have displayed clear representations of FnIII-2 and FnIII-3 domains, but lack in their ability to model the receptor structure throughout the transmembrane region and intracellular region. Due to FnIII-3 domain’s connection to these regions, it is proposed that the T-shape conformation extends all the way to the tyrosine kinase domain region.  
The beta subunit spans from the extracellular domain across the transmembrane region and into the intracellular portion of the insulin receptor. The beta subunit is composed of part of [http://en.wikipedia.org/wiki/Fibronectin fibronectin] domain III-2 and all of Fibronectin domain III-3. The beta subunit's FnIII-3 domain has links through the transmembrane region into the intracellular part of the membrane.[http://en.wikipedia.org/wiki/Transmission_electron_cryomicroscopy Cryo-EM] results have displayed clear representations of FnIII-2 and FnIII-3 domains, but lack in their ability to model the receptor structure throughout the transmembrane region and intracellular region. Due to FnIII-3 domain’s connection to these regions, it is proposed that the T-shape conformation extends all the way to the tyrosine kinase domain region.  


===Insulin===
== Function==
[[Image:Purple insulin.png|thumb|right|150px|Figure 2: Insulin molecule. [http://www.rcsb.org/structure/3I40 PDB 3I40]]]Insulin is a [http://en.wikipedia.org/wiki/Peptide_hormone peptide hormone] produced and secreted from the [http://en.wikipedia.org/wiki/Pancreatic_islets islets of Langerhans] of the pancreas in response to high blood glucose levels. Insulin is commonly considered the anabolic hormone of the body, and is the an important [http://en.wikipedia.org/wiki/Ligand ligand] in glucose homeostasis. The structure of insulin is fairly simple, it is a monomer composed of two peptide chains linked by an intermolecular disulfide bridge. Insulin initiates the transport of extracellular glucose into the cell where it can be converted into [http://en.wikipedia.org/wiki/Glycogen glycogen] for storage and later usage.
The insulin receptor's structure is critical to it's function. The receptor begins the signaling pathway that will eventually move glucose transporters to the cell surface which will allow glucose to passively defuse into the cell.  


== Function==
===Activation by Insulin===
The insulin receptor's structure is critical to it's function. The receptor begins the signaling pathway that will eventually move glucose transporters to the cell surface which will allow glucose to passively defuse into the cell. The glucose receptor is inactive in the absence of insulin. When there is a surplus of glucose circulating in the blood stream, the production of insulin is upregulated and will bind to many insulin receptors. Upon activation, it undergoes a structural [http://en.wikipedia.org/wiki/Conformational_change conformation change] from the inactive <scene name='83/832953/Simple_inactivated_receptor/3'>inverted V</scene> state to the active <scene name='83/832953/Ir_dimer_t_state/3'>T shape</scene> state. Once activated, the Beta subunits move together to autophosphorylate and initate downstream signaling by the phosphorylation of the [http://en.wikipedia.org/wiki/Insulin_receptor_substrate Insulin Receptor Substrate] (IRS), eventually resulting in glucose intake.
[[Image:Purple insulin.png|thumb|right|150px|Figure 2: Insulin molecule. [http://www.rcsb.org/structure/3I40 PDB 3I40]]]Insulin is a [http://en.wikipedia.org/wiki/Peptide_hormone peptide hormone] produced and secreted from the [http://en.wikipedia.org/wiki/Pancreatic_islets islets of Langerhans] of the pancreas in response to high blood glucose levels. Insulin is commonly considered the anabolic hormone of the body, and is the an important [http://en.wikipedia.org/wiki/Ligand ligand] in glucose homeostasis. The structure of insulin is a simple monomer composed of two peptide chains linked by an intermolecular disulfide bridge. The glucose receptor is inactive in the absence of insulin. When there is a surplus of glucose circulating in the blood stream, the production of insulin is upregulated and will bind to many insulin receptors. Upon activation, the receptor undergoes a structural [http://en.wikipedia.org/wiki/Conformational_change conformation change] from the inactive <scene name='83/832953/Simple_inactivated_receptor/3'>inverted V</scene> state to the active <scene name='83/832953/Ir_dimer_t_state/3'>T shape</scene> state. The activation and conformation change lead to downstream signaling by the phosphorylation of the [http://en.wikipedia.org/wiki/Insulin_receptor_substrate Insulin Receptor Substrate] (IRS), resulting in glucose intake. The transport of extracellular glucose into the cell allows it to be converted to [http://en.wikipedia.org/wiki/Glycogen glycogen] for storage and later usage.


===Conformation Change===
===Conformation Change===
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