Monomeric rhodopsin is sufficient for normal rhodopsin kinase (GRK1) phosphorylation and arrestin-1 binding |
| |
Authors: | Bayburt Timothy H Vishnivetskiy Sergey A McLean Mark A Morizumi Takefumi Huang Chih-Chin Tesmer John J G Ernst Oliver P Sligar Stephen G Gurevich Vsevolod V |
| |
Affiliation: | Department of Biochemistry, University of Illinois, Urbana, Illinois 61801, USA. |
| |
Abstract: | G-protein-coupled receptor (GPCR) oligomerization has been observed in a wide variety of experimental contexts, but the functional significance of this phenomenon at different stages of the life cycle of class A GPCRs remains to be elucidated. Rhodopsin (Rh), a prototypical class A GPCR of visual transduction, is also capable of forming dimers and higher order oligomers. The recent demonstration that Rh monomer is sufficient to activate its cognate G protein, transducin, prompted us to test whether the same monomeric state is sufficient for rhodopsin phosphorylation and arrestin-1 binding. Here we show that monomeric active rhodopsin is phosphorylated by rhodopsin kinase (GRK1) as efficiently as rhodopsin in the native disc membrane. Monomeric phosphorylated light-activated Rh (P-Rh*) in nanodiscs binds arrestin-1 essentially as well as P-Rh* in native disc membranes. We also measured the affinity of arrestin-1 for P-Rh* in nanodiscs using a fluorescence-based assay and found that arrestin-1 interacts with monomeric P-Rh* with low nanomolar affinity and 1:1 stoichiometry, as previously determined in native disc membranes. Thus, similar to transducin activation, rhodopsin phosphorylation by GRK1 and high affinity arrestin-1 binding only requires a rhodopsin monomer. |
| |
Keywords: | G Protein-coupled Receptors (GPCR) Phototransduction Protein Kinases Protein Phosphorylation Receptor Desensitization Rhodopsin Signal Transduction Arrestin |
本文献已被 PubMed 等数据库收录! |
|