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

FEBS Letters

Gordon, John H.¹  Rasenick, Mark M.¹ 

[1] Department Physiology and Biophysics and The Committee on Neuroscience, University of Illinois, College of Medicine, Chicago, IL 60680 USA

关键词: Signal transduction;    Receptor-effector coupling;    Cytoskeleton;    Cyclic nucleotide;    Adenylyl cyclase;    GTP-binding protein;    AAGTP;    P3-(4-azidoanilido)-P1 ′5-GTP;    G;    GTP-binding protein α subunits;    GDPβS;    guanosine ′5-O-(2-thiodiphosphate);    GTPγS;    guanosine 5′-O-(3-thiotriphosphate);    GppNHp;    guanylylimidodiphosphate;   

DOI  :  10.1016/0014-5793(88)81262-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 [G_s] or inhibit [G_i] 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 G_s, increasing under conditions favoring the stimulation of that enzyme.

【 授权许可】

Unknown