Absorption of a photon of light by rhodopsin triggers mechanisms responsible for excitation as well as regulation of the phototransduction cascade. Arrestins are a family of proteins that appear to be responsible for terminating the active state of G-protein-coupled receptors. One of the major substrates of light-dependent phosphorylation in the visual cascade of Drosophila was purified and partially sequenced. The complete primary structure of the protein was determined by isolating the corresponding gene, which revealed it to be a new isoform of arrestin, Arr2. Arr2 is 401 residues in length, and shares 47% sequence identity with the Drosophila Arr1 protein and 42% with human arrestin. We show that the two Drosophila arrestin genes are differentially regulated, and that Arr2 is a specific substrate for a calcium-dependent protein kinase. This is the first demonstration of in vivo regulation of arrestins in a transduction cascade, and provides a new level of modulation in the function of G-protein-coupled receptors.
|Number of pages||7|
|Journal||Mechanisms of Development|
|State||Published - Dec 1990|
Bibliographical noteFunding Information:
We thank Mike Socolich for his excellent help in chromosome squashes, and James Barbee for his help in the initial phase of this project. We also thank William Harris, Darwin Berg and members of the Zuker lab for their helpful comments. This work was supported by a grant from the NIH to C.S.Z. (P01 NS25916). D.P.S. is a NIH predoctoral trainee, D.M. is an MSTP trainee, and P.D. is supported by an NIH postdoctoral training grant in the visual sciences. C.S.Z. acknowledges support from the McKnight Endowment Fund for Neuroscience, the Pew Scholars Program in Biomedical Sciences, and The March of Dimes Basil O'Connor program. C.S.Z. is an investigator of the Howard Hughes Medical Institute.
- G-protein coupled receptor
ASJC Scopus subject areas
- Developmental Biology