GTP-BINDING PROTEINS that contain three non-identical subunits. They are found associated with members of the seven transmembrane domain superfamily of G-PROTEIN-COUPLED RECEPTORS. Upon activation the GTP-BINDING PROTEIN ALPHA SUBUNIT of the complex dissociates leaving a dimer of a GTP-BINDING PROTEIN BETA SUBUNIT bound to a GTP-BINDING PROTEIN GAMMA SUBUNIT.

Synonyms: Protein, Heterotrimeric G, GTP-Binding Proteins, Heterotrimeric, EC 3.6.5.1, Heterotrimeric G Proteins, Heterotrimeric GTP Binding Proteins, Heterotrimeric G Protein, G Protein, Heterotrimeric, G-Proteins, Heterotrimeric, Heterotrimeric GTP-Binding Proteins, Heterotrimeric G-Proteins