Each rhodopsin molecule binds its own arrestin

Each rhodopsin molecule binds its own arrestin.

Arrestins (Arrs) are ubiquitous regulators of the most numerous family of signaling proteins, G protein-coupled receptors. Two models of the Arr-receptor interaction have been proposed: the binding of one Arr to an individual receptor or to two receptors in a dimer. To determine the binding stoichiometry in vivo, we used rod photoreceptors where rhodopsin (Rh) and Arr are expressed at comparabl...

Motif) to Each (mhc Molecule) Its Own (binding

Dynamics of arrestin-rhodopsin interactions: acidic phospholipids enable binding of arrestin to purified rhodopsin in detergent.

We report that acidic phospholipids can restore the binding of visual arrestin to purified rhodopsin solubilized in n-dodecyl-beta-d-maltopyranoside. We used this finding to investigate the interplay between arrestin binding and the status of the retinal chromophore ligand in the receptor binding pocket. Our results showed that arrestin can interact with the late photoproduct Meta III and conve...

Regulation of rhodopsin dephosphorylation by arrestin.

We have characterized the opsin phosphatase activities in extracts of rod outer segments and determined their relationship to known protein phosphatases. The opsin phosphatase activity in the extracts was not due to protein phosphatases 1, 2B, or 2C because it was neither stimulated by Mg2+ or Ca2+/calmodulin nor inhibited by protein phosphatase inhibitors-1 or -2. Opsin phosphatase activity in...

Arrestin–GRK1 Competition Affects Rhodopsin Active Time

Phototransduction begins when a photon activates a rhodopsin molecule. Activated rhodopsin activates the G-protein transducin, which activates phosphodiesterase, leading to decreased cGMP concentration and closure of cyclic-nucleotide-gated channels. Termination of this process requires inactivation of rhodopsin and transducin. The former is mediated by arrestin, which separates the bleached ch...