Arrestin residues involved in the functional binding of arrestin to phosphorylated, photolyzed rhodopsin.
OBJECTIVE
The purpose of our study was to determine whether arrestin residues previously predicted by computational modeling to interact with an aspartic acid substituted rhodopsin tail are actually involved in interactions with phospho-residues on the rhodopsin cytoplasmic tail.


METHODS
We generated arrestin mutants with altered charges at predicted positions. These mutants were then tested for the ability to inhibit rhodopsin using both direct binding assays, as well as functional assays involving transducin inhibition assays.


RESULTS
Our results demonstrate that the computer-predicted residues are indeed involved in both the ability of the low-affinity state of arrestin to bind to rhodopsin as well as the ability of arrestin to be induced into a higher-affinity state in a phospho-residue-dependent manner.


CONCLUSIONS
Our results also suggest that positions K14, K15, R29, H301, and K300 on arrestin interact with the phosphorylated carboxyl tail of rhodopsin and that this translates to the efficient activation of arrestin.
Ascano
Maria T
MT
Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA. Mascano1@jhu.edu <Mascano1@jhu.edu>
Smith
W Clay
WC
Gregurick
Susan K
SK
Robinson
Phyllis R
PR
D000818:Animals; D019393:Arrestin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D001667:Binding, Competitive; D002417:Cattle; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010766:Phosphorylation; D010782:Photolysis; D012243:Rhodopsin / Q000737:chemistry / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000378:metabolism; D014357:Trypsin / Q000494:pharmacology
D019393:Arrestin; D012243:Rhodopsin; D014357:Trypsin