Dissecting receptor-G protein specificity using G alpha chimeras.

In conclusion, by taking advantage of the overall sequence homology and structural similarity of G alpha subunits, functional chimeric G alpha subunits can be generated and used as tools for the identification of sequence-specific factors that mediate receptor: G protein specificity. The [35S]GTP gamma S binding assay and the affinity shift activity assay are two sensitive biochemical approaches that can be used to assess receptor: G protein coupling in vitro. These in vitro assays limit confounding influences from cellular proteins and allow for the strict control of receptor: G protein ratios.