POTENTIAL ROLES OF HETEROTRIMERIC G-PROTEINS OF THE ENDOMEMBRANE SYSTEM

Heterotrimeric G proteins are recognized as versatile switches linking cell surface receptors to cellular effecters. Beside their location a t the plasma membrane G proteins are found on intracellular membranes. Studies with modulators of G protein activity suggest that G proteins associated with organelle membranes are involved in various steps of secretion and vesicular function. In contrast to hormonal responses in volving G proteins little is currently known about possible receptors or activators and effecters interacting with intracellular G proteins. This short review focuses on recent developments elucidating the role of organelle-associated G proteins.