Does subunit dissociation necessarily accompany the activation of all heterotrimeric G proteins?
Heterotrimeric (alpha beta gamma) G proteins mediate a variety of signal transduction events in virtually every cell of every eukaryotic organism. The predominant hypothesis is that dissociation of the alpha-subunit from the G beta gamma-subunit complex necessarily accompanies the activation of these proteins, and that the alpha-subunit is primarily responsible for regulating the response of effector molecules. However, there is increasing evidence that both the alpha-subunit and the beta gamma-subunit complex function in regulating effector activity. Furthermore, data for some G proteins suggest that they function as activated heterotrimers rather than as dissociated subunits.
Rebois
R V
RV
Membrane Biochemistry Section, NINDS, NIH, Bethesda, MD 20892, USA.
Warner
D R
DR
Basi
N S
NS
D000818:Animals; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000737:chemistry*; D011487:Protein Conformation; D015398:Signal Transduction / Q000502:physiology*
D019204:GTP-Binding Proteins