Arrestin

From WikiMD.com - Food, Medicine & Wellness Encyclopedia

Arrestin[edit | edit source]

Arrestin

Arrestin is a family of proteins that play a crucial role in the regulation of G protein-coupled receptors (GPCRs). These proteins are involved in the desensitization of GPCRs, which are a large family of receptors that respond to a variety of external signals. Arrestins are responsible for terminating the signaling of GPCRs and facilitating their internalization.

Structure[edit | edit source]

Arrestins are composed of two main domains, the N-domain and the C-domain, which are connected by a flexible hinge region. This structure allows arrestins to undergo conformational changes necessary for their function. The crystal structures of arrestins, such as those from the Protein Data Bank entries 1CF1 and 1G4M, have provided insights into their molecular architecture.

Arrestin structure from PDB 1CF1

Function[edit | edit source]

Arrestins are primarily known for their role in the desensitization of GPCRs. When a GPCR is activated by a ligand, it undergoes phosphorylation by G protein-coupled receptor kinases (GRKs). This phosphorylation creates a binding site for arrestins, which then bind to the receptor, preventing further G protein activation. This process effectively "arrests" the receptor, hence the name.

In addition to desensitization, arrestins also facilitate the internalization of GPCRs through clathrin-mediated endocytosis. Once internalized, receptors can be either recycled back to the cell surface or targeted for degradation.

Types of Arrestins[edit | edit source]

There are four known types of arrestins in mammals:

  • Visual arrestins: These include arrestin-1 and arrestin-4, which are primarily found in the retina and are involved in the desensitization of rhodopsin.
  • Non-visual arrestins: Arrestin-2 and arrestin-3, also known as β-arrestin-1 and β-arrestin-2, are ubiquitously expressed and regulate a wide range of GPCRs throughout the body.

Role in Signaling Pathways[edit | edit source]

Beyond their role in desensitization, arrestins are also involved in signaling pathways independent of G proteins. They can act as scaffolds for various signaling molecules, thereby influencing pathways such as the MAPK/ERK pathway, which is important for cell growth and differentiation.

Arrestin structure from PDB 1G4M

Clinical Significance[edit | edit source]

Dysregulation of arrestin function has been implicated in various diseases. For example, mutations in visual arrestins can lead to retinal degenerative diseases. Additionally, the modulation of arrestin pathways is being explored as a therapeutic strategy for conditions such as heart failure and cancer.

Related Pages[edit | edit source]


Stub icon
   This article is a protein-related stub. You can help WikiMD by expanding it!
WikiMD
Navigation: Wellness - Encyclopedia - Health topics - Disease Index‏‎ - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes

Search WikiMD

Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD

WikiMD's Wellness Encyclopedia

Let Food Be Thy Medicine
Medicine Thy Food - Hippocrates

Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates, categories Wikipedia, licensed under CC BY SA or similar.

Contributors: Prab R. Tumpati, MD