Heterotrimeric G-protein complexes couple extracellular signals via cell surface receptors to downstream enzymes called effectors. Heterotrimeric G-protein complexes, together with their cognate receptors and effectors, operate at the apex of signal transduction. In plants, the number of G-protein complex components is dramatically less than in other multicellular eukaryotes. An understanding of how multiple signals propagate transduction through the G-protein node can be found in the unique structural and kinetic properties of the plant heterotrimeric G-protein complex. This review addresses these unique features and speculates on why the repertoire of G-protein signaling elements is dramatically simpler than that in all other multicellular eukaryotes.