In situ binding of a photo-affinity GTP analog to synaptic membrane G-proteins. Distribution of bound GTP analog reflects the status of adenylate cyclase.

Abstract

Regulation of synaptic membrane adenylate cyclase is likely to involve interaction between neurotransmitter receptors, G-proteins and the adenylate cyclase catalytic unit as well as several other membrane proteins and lipids. Despite intensive study of this system, regulation of guanine nucleotide binding by the G-proteins which stimulate [Gs] or inhibit [Gi] adenylate cyclase has been examined only when those proteins have been purified and removed from the influence of the membrane environment. The hydrolysis-resistant photoaffinity GTP-analog, P3-(4-azidoanilido)-P1 5'-GTP (AAGTP) is able to bind specifically to the G-proteins in rat cerebral cortex synaptic membranes and, in this study, we have used this probe to examine the specificity and selectivity of guanine nucleotide binding to each G-protein without removing those proteins from the synaptic membrane. Marked differences were noted between guanine nucleotide binding data obtained with detergent-soluble G-proteins and data from this in situ approach. In these studies it was found that the affinity of the G-proteins binding AAGTP correlated well with the expression of adenylate cyclase activity, the affinity of both forms of Gs increasing under conditions favoring the stimulation of that enzyme.

Cite this paper

@article{Gordon1988InSB, title={In situ binding of a photo-affinity GTP analog to synaptic membrane G-proteins. Distribution of bound GTP analog reflects the status of adenylate cyclase.}, author={James H. Gordon and Mark M. Rasenick}, journal={FEBS letters}, year={1988}, volume={235 1-2}, pages={201-6} }