Anti-Retinal S antigen/SAG Antibody Picoband® Fluoro488 Conjugated

S-arrestin is a protein that in humans is encoded by the SAG gene. Members of arrestin/beta-arrestin protein family are thought to participate in agonist-mediated desensitization of G-protein-coupled receptors and cause specific dampening of cellular responses to stimuli such as hormones, neurotransmitters, or sensory signals. S-arrestin, also known as S-antigen, is a major soluble photoreceptor protein that is involved in desensitization of the photoactivated transduction cascade. It is expressed in the retina and the pineal gland and inhibits coupling of rhodopsin to transducin in vitro. Additionally, S-arrestin is highly antigenic, and is capable of inducing experimental autoimmune uveoretinitis. Mutations in this gene have been associated with Oguchi disease, a rare autosomal recessive form of night blindness.

Arrestin is one of the major proteins of the ros (retinal rod outer segments) ; it binds to photoactivated- phosphorylated rhodopsin, thereby apparently preventing the transducin-mediated activation of phosphodiesterase.

1. Calabrese, G., Sallese, M., Stornaiuolo, A., Stuppia, L., Palka, G., De Blasi, A. Chromosome mapping of the human arrestin (SAG), beta-arrestin 2 (ARRB2), and beta-adrenergic receptor kinase 2 (ADRBK2) genes. Genomics 23: 286-288, 1994. 2. Yamaki, K., Tsuda, M., Kikuchi, T., Chen, K.-H., Huang, K.-P., Shinohara, T. Structural organization of the human S-antigen gene: cDNA, amino acid, intron, exon, promoter, in vitro transcription, retina, and pineal gland. J. Biol. Chem. 265: 20757-20762, 1990.

Nucleus, nucleoplasm . Cytoplasm . Localized in cytoplasmic mRNP granules containing untranslated mRNAs. These granules are not identical with P bodies or stress granules. .