Arrestin

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arrestin, beta 1
Identifiers
Symbol	ARRB1 ARR1
HUGO	711
Entrez	408
OMIM	107940
RefSeq	NM_004041
UniProt	P49407
Other data
Locus	Chr. 11 q13

arrestin, beta 2
Identifiers
Symbol	ARRB2 ARR2
HUGO	712
Entrez	409
OMIM	107941
RefSeq	NM_004313
UniProt	P32121
Other data
Locus	Chr. 17 p13

The arrestins are a family of proteins that are important for regulating signal transduction within cells. Arrestins were originally described as proteins that bind specifically to active (phosphorylated) G-protein coupled receptors (GPCRs), and arrest or reduce signaling by these receptors. However, recent research continues to expand the known actions of arrestins, which can bind to other classes of receptors and can directly activate signaling pathways on their own.

Different arrestins can reduce the activity of their target GPCRs in several different ways. The simplest mechanism for an arrestin to inhibit the activation of its target is for it to bind to the intracellular domain of the GPCR in such a way that the binding site for the heterotrimeric G-protein is blocked, preventing extra cellular signals from activating the pathway. Another regulatory mechanism employed by certain arrestin family members is to link their target proteins to elements of the membrane internalization machinery which leads to the degradation of the receptor proteins within lysosomes.

The most well known family member is β-Arrestin which binds to sites on the β-Adrenergic receptor which are phosphorylated by the β-adrenergic receptor kinase.

It should be noted that arrestins are produced endogenously within cells and do not diffuse across cellular membranes.