
26  structures 291  species 2  interactions 1981  sequences 29  architectures

Family: Arrestin_C (PF02752)

Summary: Arrestin (or S-antigen), C-terminal domain


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Arrestin Edit Wikipedia article

S-antigen; retina and pineal gland (arrestin)
Crystallographic structure of the bovine arrestin-S.[1]
Symbol SAG
Alt. symbols arrestin-1
Entrez 6295
HUGO 10521
OMIM 181031
RefSeq NM_000541
UniProt P10523
Other data
Locus Chr. 2 q37.1
arrestin beta 1
Symbol ARRB1
Alt. symbols ARR1, arrestin-2
Entrez 408
HUGO 711
OMIM 107940
RefSeq NM_004041
UniProt P49407
Other data
Locus Chr. 11 q13
arrestin beta 2
Symbol ARRB2
Alt. symbols ARR2, arrestin-3
Entrez 409
HUGO 712
OMIM 107941
RefSeq NM_004313
UniProt P32121
Other data
Locus Chr. 17 p13
arrestin 3, retinal (X-arrestin)
Symbol ARR3
Alt. symbols ARRX, arrestin-4
Entrez 407
HUGO 710
OMIM 301770
RefSeq NM_004312
UniProt P36575
Other data
Locus Chr. X q

Arrestins are a small family of proteins important for regulating signal transduction.[2][3]


Arrestins were first discovered as a part of a conserved two-step mechanism for regulating the activity of G protein-coupled receptors (GPCRs) in the visual rhodopsin system by Hermann Kühn and co-workers[4] and in the β-adrenergic system by Martin J. Lohse and co-workers.[5][6] In response to a stimulus, GPCRs activate heterotrimeric G proteins. In order to turn off this response, or adapt to a persistent stimulus, active receptors need to be desensitized. The first step is phosphorylation by a class of serine/threonine kinases called G protein coupled receptor kinases (GRKs). GRK phosphorylation specifically prepares the activated receptor for arrestin binding. Arrestin binding to the receptor blocks further G protein-mediated signaling and targets receptors for internalization, and redirects signaling to alternative G protein-independent pathways, such as β-arrestin signaling. In addition to GPCRs, arrestins bind to other classes of cell surface receptors and a variety of other signaling proteins.[7]


Mammals express four arrestin subtypes and each arrestin subtype is known by multiple aliases. The systematic arrestin name (1-4) plus the most widely used aliases for each arrestin subtype are listed in bold below:

  • Arrestin-1 was originally identified as the S-antigen (SAG) causing uveitis (autoimmune eye disease), then independently described as a 48 kDa protein that binds light-activated phosphorylated rhodopsin before it became clear that both are one and the same. It was later renamed visual arrestin, but when another cone-specific visual subtype was cloned the term rod arrestin was coined. This also turned out to be a misnomer: arrestin-1 expresses at comparable very high levels in both rod and cone photoreceptor cells.
  • Arrestin-3. The second non-visual arrestin cloned was first termed β-arrestin-2 (retroactively changing the name of β-arrestin into β-arrestin-1), even though by that time it was clear that non-visual arrestins interact with hundreds of different GPCRs, not just with β2-adrenergic receptor. Systematic names, arrestin-2 and arrestin-3, respectively, were proposed soon after that.
  • Arrestin-4 was cloned by two groups and termed cone arrestin, after photoreceptor type that expresses it, and X-arrestin, after the chromosome where its gene resides. In the HUGO database its gene is called arrestin-3.

Fish and other vertebrates appear to have only three arrestins: no equivalent of arrestin-2, which is the most abundant non-visual subtype in mammals, was cloned so far. The proto-chordate C. intestinalis (sea squirt) has only one arrestin, which serves as visual in its mobile larva with highly developed eyes, and becomes generic non-visual in the blind sessile adult. Conserved positions of multiple introns in its gene and those of our arrestin subtypes suggest that they all evolved from this ancestral arrestin.[8] Lower invertebrates, such as roundworm C. elegans, also have only one arrestin. Insects have arr1 and arr2, originally termed “visual arrestins” because they are expressed in photoreceptors, and one non-visual subtype (kurtz in Drosophila). Later arr1 and arr2 were found to play an important role in olfactory neurons and renamed “sensory”. Fungi have distant arrestin relatives involved in pH sensing.

Tissue distribution[edit]

One or more arrestin is expressed in virtually every eukaryotic cell. In mammals, arrestin-1 and arrestin-4 are largely confined to photoreceptors, whereas arrestin-2 and arrestin-3 are ubiquitous. Neurons have the highest expression level of both non-visual subtypes. In neuronal precursors both are expressed at comparable levels, whereas in mature neurons arrestin-2 is present at 10-20 fold higher levels than arrestin-3.


Arrestins block GPCR coupling to G proteins via two mechanisms. First, arrestin binding to the cytoplasmic tip of the receptor occludes the binding site for the heterotrimeric G-protein, preventing its activation (desensitization). Second, arrestins link the receptor to elements of the internalization machinery, clathrin and clathrin adaptor AP2, which promotes receptor internalization via coated pits and subsequent transport to internal compartments, called endosomes. Subsequently, the receptor could be either directed to degradation compartments (lysosomes) or recycled back to the plasma membrane where it can once more act as a signal. The strength of arrestin-receptor interaction plays a role in this choice: tighter complexes tend to increase the probability of receptor degradation, whereas more transient complexes favor recycling, although this “rule” is far from absolute.


Arrestins are elongated molecules, in which several intra-molecular interactions hold the relative orientation of the two domains. In unstimulated cell arrestins are localized in the cytoplasm in this basal “inactive” conformation. Active phosphorylated GPCRs recruit arrestin to the plasma membrane. Receptor binding induces a global conformational change that involves the movement of the two arrestin domains and the release of its C-terminal tail that contains clathrin and AP2 binding sites. Increased accessibility of these sites in receptor-bound arrestin targets the arrestin-receptor complex to the coated pit. Arrestins also bind microtubules (part of the cellular “skeleton”), where they assume yet another conformation, different from both free and receptor-bound form. Microtubule-bound arrestins recruit certain proteins to the cytoskeleton, which affects their activity and/or redirects it to microtubule-associated proteins.

Arrestins shuttle between cell nucleus and cytoplasm. Their nuclear functions are not fully understood, but it was shown that all four mammalian arrestin subtypes remove some of their partners, such as protein kinase JNK3 or the ubiquitin ligase Mdm2, from the nucleus. Arrestins also modify gene expression by enhancing transcription of certain genes.

Arrestin (or S-antigen), N-terminal domain
PDB 1cf1 EBI.jpg
Structure of arrestin from bovine rod outer segments.[1]
Symbol Arrestin_N
Pfam PF00339
Pfam clan CL0135
InterPro IPR011021
SCOP 1cf1
Arrestin (or S-antigen), C-terminal domain
PDB 1g4m EBI.jpg
Structure of bovine beta-arrestin.[9]
Symbol Arrestin_C
Pfam PF02752
Pfam clan CL0135
InterPro IPR011022
SCOP 1cf1


  1. ^ a b PDB 1CF1; Hirsch JA, Schubert C, Gurevich VV, Sigler PB (April 1999). "The 2.8 A crystal structure of visual arrestin: a model for arrestin's regulation". Cell 97 (2): 257–69. doi:10.1016/S0092-8674(00)80735-7. PMID 10219246. 
  2. ^ Moore CA, Milano SK, Benovic JL (2007). "Regulation of receptor trafficking by GRKs and arrestins". Annu. Rev. Physiol. 69: 451–82. doi:10.1146/annurev.physiol.69.022405.154712. PMID 17037978. 
  3. ^ Lefkowitz RJ, Shenoy SK (April 2005). "Transduction of receptor signals by beta-arrestins". Science 308 (5721): 512–7. doi:10.1126/science.1109237. PMID 15845844. 
  4. ^ Wilden U, Hall SW, Kühn H (May 1986). "Phosphodiesterase activation by photoexcited rhodopsin is quenched when rhodopsin is phosphorylated and binds the intrinsic 48-kDa protein of rod outer segments". Proc Natl Acad Sci USA 83 (5): 1174–1178. doi:10.1073/pnas.83.5.1174. PMC 323037. PMID 3006038. 
  5. ^ Lohse MJ, Benovic JL, Codina J, Caron MG, Lefkowitz RJ (June 1990). "β-Arrestin: a protein that regulates β-adrenergic receptor function". Science 248 (4962): 1547–1550. doi:10.1126/science.2163110. PMID 2163110. 
  6. ^ Gurevich VV, Gurevich EV (June 2006). "The structural basis of arrestin-mediated regulation of G-protein-coupled receptors". Pharmacol. Ther. 110 (3): 465–502. doi:10.1016/j.pharmthera.2005.09.008. PMC 2562282. PMID 16460808. 
  7. ^ Gurevich VV, Gurevich EV (February 2004). "The molecular acrobatics of arrestin activation". Trends Pharmacol. Sci. 25 (2): 105–11. doi:10.1016/ PMID 15102497. 
  8. ^ Gurevich EV, Gurevich VV (2006). "Arrestins: ubiquitous regulators of cellular signaling pathways". Genome Biol. 7 (9): 236. doi:10.1186/gb-2006-7-9-236. PMC 1794542. PMID 17020596. 
  9. ^ Han M, Gurevich VV, Vishnivetskiy SA, Sigler PB, Schubert C (September 2001). "Crystal structure of beta-arrestin at 1.9 A: possible mechanism of receptor binding and membrane Translocation". Structure 9 (9): 869–80. doi:10.1016/S0969-2126(01)00644-X. PMID 11566136. 

External links[edit]



Arrestin (or S-antigen), C-terminal domain Provide feedback

Ig-like beta-sandwich fold. Scop reports duplication with N-terminal domain.

Literature references

  1. Palczewski K; , Protein Sci 1994;3:1355-1361.: Structure and functions of arrestins. PUBMED:7833798 EPMC:7833798

  2. Granzin J, Wilden U, Choe HW, Labahn J, Krafft B, Buldt G; , Nature 1998;391:918-921.: X-ray crystal structure of arrestin from bovine rod outer segments. PUBMED:9495348 EPMC:9495348

  3. Hirsch JA, Schubert C, Gurevich VV, Sigler PB; , Cell 1999;97:257-269.: The 2.8 A crystal structure of visual arrestin: a model for arrestin's regulation. PUBMED:10219246 EPMC:10219246

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR011022

Arrestins comprise a family of closely-related proteins. In addition to the inactivation of G protein-coupled receptors, arrestins have been implicated in the endocytosis of receptors and cross talk with other signalling pathways. S-Arrestin (retinal S-antigen) is a major protein of the retinal rod outer segments. It interacts with photo-activated phosphorylated rhodopsin, inhibiting or 'arresting' its ability to interact with transducin [PUBMED:15335861]. Beta-arrestin-1 and -2, which regulate the function of beta-adrenergic receptors by binding to their phosphorylated forms, impairing their capacity to activate G(S) proteins; Cone photoreceptors C-arrestin (arrestin-X) [PUBMED:7720881], which could bind to phosphorylated red/green opsins; and Drosophila phosrestins I and II, which undergo light-induced phosphorylation, and probably play a role in photoreceptor transduction [PUBMED:8452755, PUBMED:1517224, PUBMED:2158671].

The crystal structure of bovine retinal arrestin comprises two domains of antiparallel beta-sheets connected through a hinge region and one short alpha-helix on the back of the amino-terminal fold [PUBMED:9495348].

This C-terminal domain consists of an immunoglobulin-like beta-sandwich structure. This domain is found in arrestins and in other proteins including arrestin domain-containing proteins, protein ROD1 [PUBMED:8621680] and ROG3 [PUBMED:12163175] and thioredoxin-interacting protein [PUBMED:17603038].

Domain organisation


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Pfam Clan

This family is a member of clan Arrestin_N-like (CL0135), which has the following description:

The families in this clan are involved in vacuolar protein trafficking, G protein signal termination and sporulation. The Arrestin N terminal domain has an Ig-like beta sandwich fold which binds to receptors and impairs their capacity to active G proteins [1]. Arrestins have also been implicated in the endocytosis of receptors and cross talk with other signalling pathways [2].

The clan contains the following 6 members:

Arrestin_C Arrestin_N Bul1_N LDB19 Spo0M Vps26



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Curation and family details


Curation View help on the curation process

Seed source: Prosite
Previous IDs: arrestin_C;
Type: Domain
Author: Finn RD, Griffiths-Jones SR
Number in seed: 173
Number in full: 1981
Average length of the domain: 151.20 aa
Average identity of full alignment: 19 %
Average coverage of the sequence by the domain: 30.82 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
Model details:
Parameter Sequence Domain
Gathering cut-off 24.9 24.9
Trusted cut-off 24.9 24.9
Noise cut-off 24.8 24.8
Model length: 136
Family (HMM) version: 17
Download: download the raw HMM for this family

Species distribution

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There are 2 interactions for this family. More...

Arrestin_N Arrestin_C


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Arrestin_C domain has been found. There are 26 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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