arrestin, PRI, phosrestin I, Β-Arrestin, ArrB
a protein that interacts stoichiometrically with activated rhodopsin, inhibiting its ability to interact with the G protein, transducin, thus terminating the visual response
Please see the JBrowse view of Dmel\Arr2 for information on other features
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AlphaFold produces a per-residue confidence score (pLDDT) between 0 and 100. Some regions with low pLDDT may be unstructured in isolation.
Gene model reviewed during 5.46
There is only one protein coding transcript and one polypeptide associated with this gene
39 (kD)
Phosphorylated upon light exposure.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Arr2 using the Feature Mapper tool.
The testis specificity index was calculated from modENCODE tissue expression data by Vedelek et al., 2018 to indicate the degree of testis enrichment compared to other tissues. Scores range from -2.52 (underrepresented) to 5.2 (very high testis bias).
Eye-enriched transcripts determined by ratio of expression level in wild-type heads. versus expression level in so heads.
In flies reared in the dark, ~20-30% of Arr2 is immunolocalized to the rhabdomere, whilst the remaining ~70-80% localizes in the cell body cytoplasm.
Arr2 protein is detected in all rhabdomeres of the adult visual system.
JBrowse - Visual display of RNA-Seq signals
View Dmel\Arr2 in JBrowse3-26
3-20.5
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see JBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
Light-dependent trafficking of Arr2 protein is regulated by direct interaction with phosphoinositides and is required for light adaptation in the photoreceptor cells.
Area matching Drosophila EST AI297861. This EST forms a contig with ESTs AA697916 and AI063366 which overlap 5' end of Drosophila 49KDa phosphoprotein gene, Acc. No. M32141.
Phosphorylation of Arr2 protein is necessary for its release from rhodopsin.
Phosrestin 1 is phosphorylated by the CaMKII kinase. The earliest light induced phosphorylation in the photoreceptor is the phosphorylation of a single site of Arr2 by a kinase dependent on both Ca2+ and calmodulin. The kinase that is responsible for the phosphorylation of Arr2 is CaMKII. Results suggest CaMKII may play a role in regulating light adaptation in photoreceptors.
In disrupted photoreceptor cells metarhodopsin is not stabilised until arrestin is present. In intact photoreceptor cels significant metarhodopsin stabilisation occurs even in the absence of bound arrestin.
A model for metarhodopsin inactivation has been formalised in which the stochiometric binding of arrestin determines the receptor inactivation rate. This model is supported by electrophysiological measurements of metarhodopsin inactivation in dissociated photoreceptors where cytosolic arrestin levels are genetically and physiologically manipulated.
Arr2 undergoes light-induced phosphorylation on a subsecond time scale, which is faster than that of any other protein in vivo. Phosphorylation is dependent upon the activation of phosphoinositide-specific phospholipase (PI-PLC), norpA. inaC is dispensible for phosphorylation. Phosphorylation is catalysed by a class of calmodulin-dependent kinase (CaMK) in vitro and Arr2 has a unique phosphorylation site at S366.
Arr1 and Arr2 proteins have a similar function in regulating photoreceptor cell deactivation. The deactivation of the visual response in Arr2 mutants is primarily determined by Arr1 protein. Although the termination of the phototransduction cascade in wild type photoreceptors is determined by the concerted action of several feedback regulatory steps, in the absence of arrestins the termination of the phototransduction process becomes rate-limited by the slow decay of metarhodopsin.
Encodes a Drosophila homologue of mammalian arrestin, a protein that is phosphorylated by exposure to light in wild-type but not in ninaE flies which lack rhodopsin in photoreceptor cells 1-6, nor norpA flies which are deficient in phospholipase C activity. Phosphorylation dependent on the presence of Ca++, whose intracellular levels are regulated by phospholipase C.
Phosphorylation of retina-specific polypeptides 80 and 49 may be involved in some early stages of photoreceptor excitation or its modulation.
