Application of surface plasmon resonance for analysis of protein-protein interactions in the G protein-mediated...

Hundreds of extracellular stimuli are received by cells via the pathways consisting of three basic components: cell-surface receptors, heterotrimeric G proteins, and intracellular effector enzymes or ion channels. A number of additional molecules, including G protein-coupled receptor kinases (GRKs), phosducin and Ca(2+)-binding proteins modulate signal transduction through these cascades. Understanding how these universal pathways work requires a detailed analysis of the interactions between these proteins. The recently emerged technology of surface plasmon resonance (SPR) can study protein-protein interactions by measuring not only the equilibrium binding constants, but also the association and dissociation rates. This article reviews experimental design used by researchers to analyze different components of the G protein pathway by SPR and focuses on the insights this technique provides regarding the kinetics, structure-function aspects and regulation of specific molecular events in the cascade.