Editing Insulin receptor (section)

== Signal transduction pathway ==
The insulin receptor is a type of [[tyrosine kinase receptor]], in which the binding of an agonistic ligand triggers [[autophosphorylation]] of the tyrosine residues, with each subunit phosphorylating its partner. The addition of the phosphate groups generates a binding site for the [[insulin receptor substrate]] (IRS-1), which is subsequently activated via phosphorylation. The activated IRS-1 initiates the signal transduction pathway and binds to [[phosphoinositide 3-kinase]] (PI3K), in turn causing its activation. This then catalyses the conversion of [[Phosphatidylinositol 4,5-bisphosphate]] into [[Phosphatidylinositol (3,4,5)-trisphosphate|Phosphatidylinositol 3,4,5-trisphosphate]] (PIP<sub>3</sub>). PIP<sub>3</sub> acts as a secondary messenger and induces the activation of phosphatidylinositol dependent protein kinase, which then activates several other kinases – most notably [[protein kinase B]], (PKB, also known as Akt). PKB triggers the translocation of glucose transporter ([[GLUT4]]) containing vesicles to the cell membrane, via the activation of [[SNARE (protein)|SNARE]] proteins, to facilitate the diffusion of glucose into the cell. PKB also phosphorylates and inhibits [[Glycogen synthase kinase 3|glycogen synthase kinase]], which is an enzyme that inhibits [[glycogen synthase]]. Therefore, PKB acts to start the process of glycogenesis, which ultimately reduces blood-glucose concentration.<ref>{{Cite book |last=Berg JM, Tymoczko JL, Gatto GJ, Stryer L |title=Biochemistry |publisher=W H Freeman/Macmillan International |year=2019 |isbn=978-1-319-11465-7 |edition=9th |page=897}}</ref>

{{Gallery
|title=Signal transduction of Insulin
|width=700 | height=230
|align=center
|File:insulin glucose metabolism.jpg
 |'''Effect of insulin on glucose uptake and metabolism.''' Insulin binds to its receptor (1), which, in turn, starts many protein activation cascades (2). These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5), and fatty acid synthesis (6).
|File:Signal Transduction Diagram- Insulin.svg
 |'''Signal transduction of Insulin:''' At the end of the transduction process, the activated protein binds to the [[c|'''PIP<sub>2</sub>''']] phospholipids embedded in the membrane.
}}