True about G protein-coupled receptors is
Heteromeric g protein located inside the cell are activated by g protein coupled receptors that span the cell membrane. Signaling molecules bind to a domain of GPCR out side the cell and an intracellular GPCR domain then in turn activates a paicular G protein Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:540,541,542
G proteins bind to hormones on the cell surface
All the three subunits alpha, beta and gamma should bind to each other for G protein to act
G proteins act as inhibitory and excitatory because of difference in alpha subunit
G protein is bound to GTP in resting state
General physiology