title: A variant of arrestin-1 binds rod outer segment membranes in a light-independent manner.
abstract: A 50-kDa-polypeptide band peripherally bound to retinal rod outer segment (ROS) membranes was purified by anion-exchange chromatography. When the 50-kDa protein was compared with purified arrestin-1, it was observed that: (1) both proteins comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and were recognized by either anti-50-kDa protein polyclonal antibodies or anti-arrestin-1 monoclonal antibodies; (2) protein fragments and peptide fingerprint maps obtained following limited and complete proteolysis with specific proteases were very similar for both molecules; and (3) several chromatographically-purified tryptic peptides from the 50-kDa protein possessed the same amino acid composition as tryptic peptides deduced from the reported arrestin-1 primary structure. Consequently, arrestin-1 and the purified 50-kDa protein must correspond to variants of the same molecule. However, in contrast to arrestin-1 that associated to the ROS membranes only in the presence of light and ATP, the 50-kDa protein interacted with the ROS membranes in a light-independent manner, either in the presence or absence of ATP. These results clearly established that phosphorylated and illuminated rhodopsin is not the membrane anchor for this variant of arrestin-1.
authors.affiliation: Departamento de Biología Celular, División de Ciencias Biológicas, Universidad Simón Bolívar, Apartado 89.000, Valle de Sartenejas, Baruta, Caracas 1081-A, Venezuela.
authors.forename: Graciela L
authors.initials: GL
authors.lastname: Uzcanga
authors.forename: Aniuska R
authors.initials: AR
authors.lastname: Becerra
authors.forename: Deisy
authors.initials: D
authors.lastname: Perdomo
authors.forename: José
authors.initials: J
authors.lastname: Bubis
mesh_terms: D000818:Animals; D019393:Arrestin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D008970:Molecular Weight; D010766:Phosphorylation / Q000528:radiation effects; D011485:Protein Binding / Q000528:radiation effects; D012374:Rod Cell Outer Segment / Q000378:metabolism* / Q000528:radiation effects; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D019393:Arrestin