Robert J. Lefkowitz

TL;DR: This review focuses on the regulation of GRK activity by a variety of allosteric and other factors: agonist-stimulated GPCRs, beta gamma subunits of heterotrimeric GTP- binding proteins, phospholipid cofactors, the calcium-binding proteins calmodulin and recoverin, posttranslational isoprenylation and palmitoylation, autophosphorylation, and protein kinase C-mediated GRK phosphorylation.

TL;DR: The molecular mechanisms underlying rapid βAR desensitization do not appear to require internalization of the receptors, but rather an alteration in the functioning of βAR themselves that uncouples the receptors from the stimulatory G protein Gs.

TL;DR: A mechanism previously shown to mediate uncoupling of the β2-adrenergic receptor from Gs and thus heterologous desensitization (PKA-mediated receptor phosphorylation), also serves to ‘switch’ coupling of this receptor fromGs to Gi and initiate a new set of signalling events.

TL;DR: The signaling capacities of these versatile adapter molecules are reviewed and the possible implications for cellular processes such as chemotaxis and apoptosis are discussed.

TL;DR: The experimental findings with the mutant receptor cannot be adequately rationalized within the theoretical framework of the Ternary Complex Model, and an extended version of this model that includes an explicit isomerization of the receptor to an active state closely models all the findings for both the mutant and the wild-type receptors.