View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1411 (1999) 334^350 Review Guanylate cyclase and the cNO/cGMP signaling pathway John W. Denninger a, Michael A. Marletta a;b;c;* a 5315A Medical Sciences I, Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive Ann Arbor, MI 48109-0606, USA b Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109-0606, USA c Interdepartmental Program in Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA Received 13 August 1998; received in revised form 30 November 1998; accepted 16 December 1998 Abstract Signal transduction with the diatomic radical nitric oxide (NO) is involved in a number of important physiological processes, including smooth muscle relaxation and neurotransmission. Soluble guanylate cyclase (sGC), a heterodimeric enzyme that converts guanosine triphosphate to cyclic guanosine monophosphate, is a critical component of this signaling pathway. sGC is a hemoprotein; it is through the specific interaction of NO with the sGC heme that sGC is activated. Over the last decade, much has been learned about the unique heme environment of sGC and its interaction with ligands like NO and carbon monoxide. This review will focus on the role of sGC in signaling, its relationship to the other nucleotide cyclases, and on what is known about sGC genetics, heme environment and catalysis. The latest understanding in regard to sGC will be incorporated to build a model of sGC structure, activation, catalytic mechanism and deactivation. ß 1999 Elsevier Science B.V. All rights reserved. Keywords: Guanylate cyclase; Cyclic guanosine monophosphate; Nitric oxide; Carbon monoxide; Heme Contents 1. Introduction .......................................................... 335 2. Historical perspective . ................................................. 335 3. Signaling with the cNO/cGMP pathway ...................................... 336 4. The nucleotide cyclase family: sGC, pGC and AC . ............................ 337 Abbreviations: AC, adenylate cyclase; ATP, adenosine 5P-triphosphate; L11385,NH2-terminal heme binding domain of the L1 subunit of soluble guanylate cyclase; cAMP, cyclic adenosine 3P,5P-monophosphate; cGMP, cyclic guanosine 3P,5P-monophosphate; CO, carbon monoxide; CO-sGC, soluble guanylate cyclase with nitric oxide bound in the distal heme coordination site; EDRF, endothelium derived relaxing factor; EPR, electron paramagnetic resonance spectroscopy; FTIR, Fourier transform infrared spectroscopy; GTP, guanosine c 3 3 5P-triphosphate; NO, nitric oxide; NO2 , nitrite; NO3 , nitrate; NOS, nitric oxide synthase; NO-sGC, soluble guanylate cyclase with nitric oxide bound in the distal heme coordination site; PDE, phosphodiesterase; pGC, particulate guanylate cyclase; sGC, soluble guanylate cyclase; RR, resonance Raman spectroscopy * Corresponding author, at address a. Fax: +1 (734) 6475687; E-mail: [email protected] 0005-2728 / 99 / $ ^ see front matter ß 1999 Elsevier Science B.V. All rights reserved. PII: S0005-2728(99)00024-9 BBABIO 44737 23-4-99 Cyaan Magenta Geel Zwart J.W. Denninger, M.A. Marletta / Biochimica et Biophysica Acta 1411 (1999) 334^350 335 5. Soluble guanylate cyclase genetics and isoforms ................................ 339 6. Puri¢cation from mammalian tissue and expression systems ....................... 341 7. Heme environment ..................................................... 342 8. Catalysis . ........................................................... 343 9. Model of sGC structure and function ....................................... 344 10. Conclusion ........................................................... 346 Acknowledgements . ...................................................... 346 References ............................................................... 346 1. Introduction protein kinase, cGMP-gated cation channels and cGMP-regulated phosphodiesterase. As will be de- Soluble guanylate1 cyclase (sGC) is the only con- scribed below, nearly 30 years of study of sGC clusively proven receptor for nitric oxide (cNO), a have given us an outline of sGC structure and func- signaling agent produced by the enzyme nitric oxide tion; however, many facets of sGC structure and synthase (NOS) from the amino acid L-arginine. As function, especially at the molecular level, remain shown in Fig. 1, sGC catalyzes the conversion of to be discovered. guanosine 5P-triphosphate (GTP) to cyclic guanosine 3P,5P-monophosphate (cGMP). Because it is one of two enzymes (the other is the membrane-bound pep- 2. Historical perspective tide-receptor guanylate cyclase) that produce cGMP, and because it is the only de¢nitive receptor for cNO, Although both sGC and its product, cGMP, were sGC is intimately involved in many signal transduc- identi¢ed in the 1960s, it has been only within the tion pathways, most notably in the cardiovascular last 10 years that the complete outline of the cNO/ system (e.g., in the regulation of vascular tone and cGMP signaling pathway has been understood. After platelet function) and in the nervous system (e.g. in the discovery of cAMP in 1958 [1] and the initial neurotransmission and, possibly, long-term potentia- elucidation of its role in physiology (for early reviews tion and depression). Soluble guanylate cyclase is a see [2,3]), the search for other physiologically rele- heterodimeric protein composed of K and L subunits; vant cyclic nucleotides began. In 1963, cGMP was in addition, it is a hemoprotein (see Fig. 2). cNO detected in the urine of rats [4]; several years later, binds to the sGC heme; this binding event activates guanylate cyclase was found in mammalian tissues the enzyme. The activation of sGC and the subse- [5^9]. In 1977, cNO 9 both as cNO gas and as cNO quent rise in cGMP concentration are what allow released from vasodilators like nitroglycerin and sGC to transmit an cNO signal to the downstream nitroprusside 9 was shown to activate guanylate elements of the signaling cascade-cGMP-dependent cyclase [10^13]. At that point, though, cNO was unknown in biological systems, except when exoge- nously supplied by drugs like nitroglycerin, so it was 1 Although we prefer `guanylate' cyclase (as does the Index assumed that cNO activation of sGC was a non- Medicus and the Oxford Dictionary of Biochemistry and Molec- physiological, if useful, phenomenon. ular Biology), `guanylyl' cyclase is also used. Neither of the com- The story soon became clear, however. In 1980, mon names for this enzyme is technically correct: `guanylate' refers to the anion of guanylic acid (guanosine monophosphate) Furchgott et al. were able to demonstrate the exis- and `guanylyl' refers to the acyl group derived from guanylic tence of a substance produced by the endothelium acid. that was required to mediate relaxation of blood BBABIO 44737 23-4-99 Cyaan Magenta Geel Zwart 336 J.W. Denninger, M.A. Marletta / Biochimica et Biophysica Acta 1411 (1999) 334^350 vessels [14]. They designated this substance endothe- di¡uses freely across cell membranes, obviating the lium-derived relaxing factor (EDRF). In 1986, Ignar- need for a transport system. cNO is relatively unreac- ro and Furchgott independently suggested that tive for a radical species, so that it can di¡use from a EDRF was cNO (reviewed in [15]); the next year, it cell in which it is produced to neighboring cells with- was demonstrated that this was the case [16,17]. At out being destroyed before it reaches its target. Be- c 3 3 the same time, our laboratory and others were un- cause NO is oxidized to NO2 and NO3 under phys- 3 3 raveling the story of nitrite (NO2 ) and nitrate (NO3 ) iological conditions, no separate mechanism for its production in mammals. After initial observations by destruction is required [29^31]; however, at low con- Tannenbaum and coworkers that mammals produce centrations of cNO and in the absence of proteins 3 3 NO3 and that NO3 synthesis is increased following and metals which contribute to its destruction, the 3 c immune stimulation [18^20], it was shown that NO2 decomposition of NO will be slow [29]. Most impor- 3 c and NO3 were produced by immunostimulated mac- tantly, the electronic structure of NO makes it an rophages from the amino acid arginine (reviewed in excellent ligand for heme, allowing it to bind to the [21,22]). Shortly thereafter, our laboratory and sGC heme at a low, non-toxic concentration. others demonstrated that a soluble enzyme in murine The one well-de¢ned target for cNO, of course, is macrophages, later puri¢ed and named nitric oxide sGC; however, several paths for cNO signal trans- synthase, was producing cNO from the amino acid duction which do not rely on the production of arginine [23^25]. At this point, the major compo- cGMP by sGC have been proposed, though they nents of the cNO/cGMP signaling pathway had are less clearly de¢ned than the cNO/cGMP pathway. been identi¢ed: nitric oxide synthase produces cNO, First, cNO was shown to inhibit mitochondrial cyto- which activates soluble guanylate cyclase, leading to chrome oxidase at concentrations of cNO found a subsequent increase in the concentration of cGMP. physiologically [32,33]. Second, cNO was reported to activate calcium-dependent potassium channels in vascular smooth muscle directly, though it is pos- 3. Signaling with the cNO/cGMP pathway sible that this only happens with levels of cNO