title: ATP potentiates competitive inhibition of guanylyl cyclase A and B by the staurosporine analog, Gö6976: reciprocal regulation of ATP and GTP binding.
abstract: Natriuretic peptides and ATP activate and Gö6976 inhibits guanylyl cyclase (GC)-A and GC-B. Here, the mechanism of inhibition was determined. Gö6976 progressively increased the Michaelis-Menten constant and decreased the Hill coefficient without reducing the maximal velocity of GC-A and GC-B. In the presence of 1 mm ATP, the K(i) was 1 μm for both enzymes. Inhibition of GC-B was minimal in the absence of ATP, and 1 mm ATP increased the inhibition 4-fold. In a reciprocal manner, 10 μm Gö6976 increased the potency of ATP for GC-B 4-fold. In contrast to a recent study (Duda, T., Yadav, P., and Sharma, R. K. (2010) FEBS J. 277, 2550-2553), neither staurosporine nor Gö6976 activated GC-A or GC-B. This is the first study to show that Gö6976 reduces GTP binding and the first demonstration of a competitive inhibitor of a receptor guanylyl cyclase. We conclude that Gö6976 reduces GTP binding to the catalytic site of GC-A and GC-B and that ATP increases the magnitude of the inhibition.
authors.affiliation: Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Jerid W
authors.initials: JW
authors.lastname: Robinson
authors.forename: Lincoln R
authors.initials: LR
authors.lastname: Potter
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D001665:Binding Sites; D002227:Carbazoles / Q000494:pharmacology*; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding / Q000187:drug effects; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019311:Staurosporine / Q000031:analogs & derivatives; D000099242:Atrial Natriuretic Factor Receptor B
chemical_list: D000255:Adenosine Triphosphate; D002227:Carbazoles; D004791:Enzyme Inhibitors; D006160:Guanosine Triphosphate; D017461:Receptors, Atrial Natriuretic Factor; D019311:Staurosporine; D000099242:Atrial Natriuretic Factor Receptor B; C081021:Go 6976; C091715:atrial natriuretic factor receptor A