The G beta-gamma complex (G
βγ) is a tightly bound dimeric protein complex, composed of one G
β and one G
γ subunit, and is a component of
heterotrimeric G proteins. Heterotrimeric G proteins, also called guanosine nucleotide-binding proteins, consist of three subunits, called
alpha, beta, and gamma subunits, or G
α, G
β, and G
γ. When a
G protein-coupled receptor (GPCR) is activated, G
α dissociates from G
βγ, allowing both subunits to perform their respective downstream
signaling effects. One of the major functions of G
βγ is the inhibition of the G
α subunit.