Ion channel regulation by Ras, Rho, and Rab small GTPases.

Regulation of ion channels by heterotrimeric guanosine triphosphatases (GTPases), activated by heptathelical membrane receptors, has been the focus of several recent reviews. In comparison, regulation of ion channels by small monomeric G proteins, activated by cytoplasmic guanine nucleotide exchange factors, has been less well reviewed. Small G proteins, molecular switches that control the activity of cellular and membrane proteins, regulate a wide variety of cell functions. Many upstream regulators and downstream effectors of small G proteins now have been isolated. Their modes of activation and action are understood. Recently, ion channels were recognized as physiologically important effectors of small GTPases. Recent advances in understanding how small G proteins regulate the intracellular trafficking and activity of ion channels are discussed here. We aim to provide critical insight into physiological control of ion channel function and the biological consequences of regulation of these important proteins by small, monomeric G proteins.