Coordinate Regulation of G Protein Signaling via Dynamic Interactions of Receptor and GAP

From Q-bio

G protein signaling modules are ubiquitous throughout eukaryotes and convey information with diverse patterns of response speed, sensitivity and amplification. While they contain only four proteins –- receptor, heterotrimeric G protein, GTPase-activating protein (GAP) and effector –- they display complex signal output behaviors whose underlying mechanisms have resisted analysis. We developed a kinetic model of a prototypical G protein module and determined its parameter set (reaction rate constants) by fitting to data derived from extensive in vitro steady-state GTPase measurements. We used the model and parameters to investigate the signal output behaviors of this system and their biochemical mechanisms.

A long abstract is available (pdf).