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Differential interaction of spin-labeled arrestin with inactive and active phosphorhodopsin. Proc Natl Acad Sci U S A 2006 Mar 28;103(13):4900-5



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Scopus ID

2-s2.0-33645506641   139 Citations


Arrestins regulate signaling and trafficking of G protein-coupled receptors by virtue of their preferential binding to the phosphorylated active form of the receptor. To identify sites in arrestin involved in receptor interaction, a nitroxide-containing side chain was introduced at each of 28 different positions in visual arrestin, and the dynamics of the side chain was used to monitor arrestin interaction with phosphorylated forms of its cognate receptor, rhodopsin. At physiological concentrations, visual arrestin associates with both inactive dark phosphorylated rhodopsin (P-Rh) and light-activated phosphorylated rhodopsin (P-Rh*). Residues distributed over the concave surfaces of the two arrestin domains are involved in weak interactions with both states of phosphorhodopsin, and the flexible C-terminal sequence (C-tail) of arrestin becomes dynamically disordered in both complexes. A large-scale movement of the C-tail is demonstrated by direct distance measurements using a doubly labeled arrestin with one nitroxide in the C-tail and the other in the N-domain. Despite some overlap, the molecular "footprint" of arrestin bound to P-Rh and P-Rh* is different, showing the structure of the complexes to be unique. Strong immobilizing interactions with residues in a highly flexible loop between beta-strands V and VI are only observed in complex with the activated state. This result identifies this loop as a key recognition site in the arrestin-P-Rh* complex and supports the view that flexible sequences are key elements in protein-protein interactions.

Author List

Hanson SM, Francis DJ, Vishnivetskiy SA, Kolobova EA, Hubbell WL, Klug CS, Gurevich VV


Candice S. Klug PhD Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Electron Spin Resonance Spectroscopy
Models, Molecular
Protein Binding
Protein Structure, Quaternary
jenkins-FCD Prod-411 e00897e83867fcfa48419861683711f8d99adb75