Crystal structure of cone arrestin at 2.3A: evolution of receptor specificity.

Sutton RB, Vishnivetskiy SA, Robert J, Hanson SM, Raman D, Knox BE, Kono M, Navarro J, Gurevich VV
J Mol Biol. 2005 354 (5): 1069-80

PMID: 16289201 · DOI:10.1016/j.jmb.2005.10.023

Arrestins play a fundamental role in the regulation and signal transduction of G protein-coupled receptors. Here we describe the crystal structure of cone arrestin at 2.3A resolution. The overall structure of cone visual arrestin is similar to the crystal structures of rod visual and the non-visual arrestin-2, consisting of two domains, each containing ten beta-sheets. However, at the tertiary structure level, there are two major differences, in particular on the concave surfaces of the two domains implicated in receptor binding and in the loop between beta-strands I and II. Functional analysis shows that cone arrestin, in sharp contrast to its rod counterpart, bound cone pigments and non-visual receptors. Conversely, non-visual arrestin-2 bound cone pigments, suggesting that it may also regulate phototransduction and/or photopigment trafficking in cone photoreceptors. These findings indicate that cone arrestin displays structural and functional features intermediate between the specialized rod arrestin and the non-visual arrestins, which have broad receptor specificity. A unique functional feature of cone arrestin was the low affinity for its cognate receptor, resulting in an unusually rapid dissociation of the complex. Transient arrestin binding to the photopigment in cones may be responsible for the extremely rapid regeneration and reuse of the photopigment that is essential for cone function at high levels of illumination.

MeSH Terms (36)

Alanine Amino Acid Sequence Amino Acid Substitution Animals Anura Arginine Arrestin Arrestins Asparagine Biological Evolution Cattle Conserved Sequence Crystallography, X-Ray Electrophoretic Mobility Shift Assay Escherichia coli GTP-Binding Proteins Humans Hydrogen Bonding Hydrophobic and Hydrophilic Interactions Models, Molecular Molecular Sequence Data Mutagenesis Mutation Phosphates Proline Protein Folding Protein Structure, Secondary Protein Structure, Tertiary Retinal Cone Photoreceptor Cells Retinal Rod Photoreceptor Cells Sensitivity and Specificity Sequence Homology, Amino Acid Signal Transduction Spectrum Analysis, Raman Urodela Valine

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