Monomeric rhodopsin is the minimal functional unit required for arrestin binding.
We have tested whether arrestin binding requires the G-protein-coupled receptor be a dimer or a multimer. To do this, we encapsulated single-rhodopsin molecules into nanoscale phospholipid particles (so-called nanodiscs) and measured their ability to bind arrestin. Our data clearly show that both visual arrestin and beta-arrestin 1 can bind to monomeric rhodopsin and stabilize the active metarhodopsin II form. Interestingly, we find that the monomeric rhodopsin in nanodiscs has a higher affinity for wild-type arrestin binding than does oligomeric rhodopsin in liposomes or nanodiscs, as assessed by stabilization of metarhodopsin II. Together, these results establish that rhodopsin self-association is not required to enable arrestin binding.
Tsukamoto
Hisao
H
Department of Biochemistry and Molecular Biology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA.
Sinha
Abhinav
A
DeWitt
Mark
M
Farrens
David L
DL
D019393:Arrestin / Q000737:chemistry*; D019390:Arrestins / Q000737:chemistry*; D008081:Liposomes; D053758:Nanoparticles; D010743:Phospholipids; D010766:Phosphorylation; D011485:Protein Binding; D055503:Protein Multimerization; D012243:Rhodopsin / Q000737:chemistry*; D000071557:beta-Arrestins
D019393:Arrestin; D019390:Arrestins; D008081:Liposomes; D010743:Phospholipids; D000071557:beta-Arrestins; C013110:metarhodopsins; D012243:Rhodopsin