Membrane-delimited cell signaling complexes: direct ion channel regulation by G proteins.
Ion channels are signaling molecules and by themselves perform no work. In this regard they are unlike the usual membrane enzyme effectors for G proteins. The pathways of G protein receptor, G protein and ion channels are, therefore, purely informational in function. Because a single G protein may have several ion channels as effectors, the effects should be coordinated and this seems to be the case. Inhibition of Ca2+ current and stimulation of K+ currents would have a greater impact than either alone. Additional flexibility is provided by spontaneous noise in the complexes of G protein receptor, G protein, and ion channel. By having a non-zero setpoint, the range of control is extended and the responses become bi-directional.
Brown
A M
AM
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002490:Central Nervous System / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D015290:Second Messenger Systems; D015398:Signal Transduction
D007473:Ion Channels; D019204:GTP-Binding Proteins