G proteins are important regulators of various cellular processes including motility, metabolism, and transcription. They are involved in mediating extracellular signals that trigger a cascade of intracellular responses via a series of membrane-bound receptors.
Key to the regulation of the G protein signaling cascade is the involvement of cyclic AMP (cAMP) and cyclic GMP (cGMP). One of the key functions of both molecules is to activate Guanine Exchange Factors (GEF), which in turn play a role in the activation of G proteins.
Small GTPases serve to regulate a variety of cell signaling pathways and are therefore involved in a wide range of cell functions, processes and morphology.