Insulin receptor

Insulin receptor is a transmembrane receptor that is activated by insulin, IGF-I, IGF-II and belongs to the large class of tyrosine kinase receptors. Metabolically, the insulin receptor plays a key role in the regulation of glucose homeostasis, a functional process that under degenerate conditions may result in a range of clinical manifestations including diabetes and cancer.

Structure

The insulin receptor is a heterotetrameric protein consisting of two α and two β subunits. The α and β subunits are coded by a single gene, INSR, and are joined by disulfide bonds, a mechanism parallel to that of its ligand, insulin.

Function

The insulin receptor is expressed in various tissues including liver, muscle, and adipose tissue. The primary function of the insulin receptor is its ability to regulate glucose uptake. A secondary function of the insulin receptor is to regulate cell growth and differentiation, which it does through activation of mitogenic signaling pathways.

Clinical significance

Mutations in this gene have been associated with insulin resistance, obesity, hyperinsulinemia, polycystic ovary syndrome, and type 2 diabetes. Insulin resistance and type 2 diabetes are both conditions characterized by a decrease in the effectiveness of insulin in inducing the uptake of glucose from the blood, leading to hyperglycemia and a variety of other metabolic disturbances.

See also

• Insulin
• Insulin-like growth factor
• Diabetes mellitus
• Obesity
• Polycystic ovary syndrome

References

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  Colour coded schematic of the insulin receptor
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  Insulin receptor conformation change upon binding
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  Ligand-saturated cryoEM IR structure
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  Insulin glucose metabolism
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  Signal transduction diagram: Insulin