Biased signaling has been reported with a series of G protein-coupled receptors (GPCRs), including β2-adrenergic receptor and μ-opioid receptor (OPRM1). The concept of biased signaling suggests that the agonists of one particular receptor may activate the downstream signaling pathways with different efficacies. Thus in an extreme case, agonists might activate different sets of signaling pathways, which provide a new route to develop drugs with increased efficacies and decreased side effects. Among the many factors, posttranslation modifications of receptor proteins have major roles in influencing the biased signaling. Take OPRM1, for example, the phosphorylation and palmitoylation of receptor can regulate the biased signaling induced by agonists. Thus, by modulating these posttranslation modifications, the biased signaling of GPCRs can be regulated. In addition, although it is not considered as posttranslation modification normally, the distribution of GPCRs on cell membrane, especially the distribution between lipid-raft and non-raft microdomains, also contributes to the biased signaling. Thus in this chapter, we described the methods used in our laboratory to study receptor phosphorylation, receptor palmitoylation, and membrane distribution of receptor by using OPRM1 as a model. A functional model was also provided on these posttranslational modifications at the last section of this chapter.
|Original language||English (US)|
|Title of host publication||G Protein Coupled ReceptorsModeling, Activation, Interactions and Virtual Screening|
|Publisher||Academic Press Inc.|
|Number of pages||18|
|State||Published - 2013|
|Name||Methods in Enzymology|
Bibliographical noteFunding Information:
This research was supported by the “Guangzhou International Science and Technology Cooperation Projects from Bureau of Science and Information Technology of Guangzhou Municipal Government (2012J5100007)”, the “Guangdong Natural Science Foundation (S2012010010087)”, the “National Natural Science Foundation of China (31100773)”, and the “Major New Drugs Innovation” of Major National Scientific and Technological Project (2011ZX09102-010-01). The research was also supported by NIH Grants DA023905 and DA011806.
- Biased signaling