Arrestin

Arrestin is a protein that plays a significant role in regulating signal transduction at G protein-coupled receptors. There are four known arrestin subtypes in mammals. Two are ubiquitously expressed and are known as beta-arrestin 1 and beta-arrestin 2, which are also called arrestin 2 and arrestin 3, respectively. The other two are expressed mainly in the neurons of the visual system and are known as arrestin 1 (or visual arrestin, S-antigen) and arrestin 4 (or cone arrestin, X-arrestin).

Function

Arrestins bind to the G protein-coupled receptor (GPCR) and desensitize it, preventing the receptor from activating additional G proteins, thus terminating the signal. Arrestins also serve to internalize the GPCR, acting as an adapter protein to aid in the receptor's endocytosis.

Structure

Arrestins are elongated molecules. The N- and C-domains, which are similar in structure, are each composed of a seven-strand beta-sandwich flanked by two alpha-helices. The two domains are connected by a 12-residue polar core, which is thought to be crucial for the activation of arrestin.

Clinical significance

Mutations in the arrestin genes have been associated with a number of diseases, including night blindness and Oguchi disease. In addition, arrestins have been implicated in the development of heart failure and cancer.

See also

• G protein-coupled receptor
• Signal transduction
• Beta-arrestin

References

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External links

• Arrestin at the US National Library of Medicine Medical Subject Headings (MeSH)

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