What type of receptor is the insulin receptor?

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.

Regulation of gene expression is a major component of insulin action, which is classically thought to occur via phosphorylation, relocalization and/or processing of transcriptional regulators downstream of the insulin receptor (IR) signaling cascade.

Insulin’s actions are mediated by the insulin receptor (InsR), a plasma membrane-resident glycoprotein and member of the receptor tyrosine kinase (RTK) family. … As an RTK, InsR is ligand-activated through mechanisms that are both prototypical and atypical of RTKs.

Insulin Receptors are areas on the outer part of a cell that allow the cell to join or bind with insulin that is in the blood. When the cell and insulin bind together, the cell can take glucose (sugar) from the blood and use it for energy. Phe 25B is the active site of insulin.

The insulin receptor is a member of the ligand-activated receptor and tyrosine kinase family of transmembrane signaling proteins that collectively are fundamentally important regulators of cell differentiation, growth, and metabolism.

The receptor belongs to the receptor tyrosine kinase superfamily and has orthologues in all metazoans. The structure of the unbound extracellular domain (“apo-receptor”) has been solved. Insulin binds to two distinct sites on each a subunit of the receptor, crosslinking the two receptor halves to create high affinity.

However, the existence of insulin receptors has been demonstrated in almost all tissues studied. Furthermore, certain tissues such as skeletal muscle and adipose tissue revealed the existence of insulin receptors despite the difficulty of morphological demonstration of insulin receptors in these tissues.

Insulin receptor substrate-1 (IRS1) is a substrate of the insulin receptor tyrosine kinase and appears to have a central role in the insulin-stimulated signal transduction pathway. Therefore, the IRS1 gene has been studied extensively as a candidate gene for type 2 diabetes.

At the interface between these circulating factors and insulin/glucagon secretion are GPCRs, which in islets mediate the effects of many of the circulating factors, such as glucagon-like peptide-1, free fatty acids, and catecholamines.

The insulin receptor is a dimeric protein that has a crucial role in controlling glucose homeostasis, regulating lipid, protein and carbohydrate metabolism, and modulating brain neurotransmitter levels1,2.

Insulin travels through the blood to reach your body cells, particularly your muscles and liver. When insulin reaches its target cells, it can’t get directly into the cell because it is hydrophilic. The hydrophobic membrane keeps it out. So, insulin talks to receptors on the surface of the cell.

Insulin receptors are proteins found on the surfaces of most cells in the human body. Insulin binding activates it and triggers a signaling cascade inside the cell, resulting in glucose uptake and various other metabolic and growth-related functions.

The insulin receptor is composed of two alpha subunits and two beta subunits linked by disulfide bonds. The alpha chains are entirely extracellular and house insulin binding domains, while the linked beta chains penetrate through the plasma membrane.

Abstract. Insulin binding to insulin receptor (IR) at the cell surface results in the activation of IR kinase and initiates the translocation of insulin–IR complexes to clathrin-coated pits and to early endosomes containing internalized but still active receptors.

Insulin receptor substrate (IRS) is an important ligand in the insulin response of human cells. IRS-1, for example, is an IRS protein that contains a phosphotyrosine binding-domain (PTB-domain). In addition, the insulin receptor contains a NPXY motif. The PTB-domain binds the NPXY sequence.

Type 1 Diabetes occurs when the pancreatic beta cells are destroyed by an immune-mediated process. Because the pancreatic beta cells sense plasma glucose levels and respond by releasing insulin, individuals with type 1 diabetes have a complete lack of insulin. In this disease, daily injections of insulin are needed.

Insulin initiates its action by binding to a glycoprotein receptor on the surface of the cell. This receptor consists of an alpha-subunit, which binds the hormone, and a beta-subunit, which is an insulin-stimulated, tyrosine-specific protein kinase.

Insulin initiates its cellular responses by binding to its cellular receptor, a transmembrane, multisubunit glycoprotein that contains insulin-stimulated tyrosine kinase activity [1].

Strikingly, we can identify four insulins bound to four sites in the fully liganded IR dimer (Figure 1). Because of the 2-fold symmetry, there are two distinct types of insulin and insulin-binding sites in the complex, denoted as insulins 1, 1′, 2, and 2′; and sites 1, 1′, 2, and 2′.

Scatchard analysis of binding were biphasic and showed high affinity sites with a Kd of about 1.5 nM and capacity of about 10,000 receptors per cell; low affinity sites were much more numerous with a Kd of 88 nM for mouse and 998 nM for rat.

Surrounding its core, the monomer has two extensive nonpolar surfaces. One of them is a flat one that is aromatic and gets buried when there is a dimer formation. The other surface is more extensive and disappears when a hexamer is formed. This is called the quaternary structure of insulin.

The aggregation of insulin is in fact driven by hydrophobic interaction: the same hydrophobic interaction is also likely the driving force orienting insulin monomers at lipid surfaces.

Tertiary structure The three-dimensional structure of insulin is further stabilised by disulphide bridges. These form between thiol groups (-SH) on cysteine residues (CYS above).

Insulin is an anabolic hormone that promotes glucose uptake, glycogenesis, lipogenesis, and protein synthesis of skeletal muscle and fat tissue through the tyrosine kinase receptor pathway.