title: Novel complexes of guanylate cyclase with heat shock protein 90 and nitric oxide synthase.
abstract: Soluble guanylate cyclase (sGC) is an important downstream intracellular target of nitric oxide (NO) that is produced by endothelial NO synthase (eNOS) and inducible NO synthase (iNOS). In this study, we demonstrate that sGC exists in a complex with eNOS and heat shock protein 90 (HSP90) in aortic endothelial cells. In addition, we show that in aortic smooth muscle cells, sGC forms a complex with HSP90. Formation of the sGC/eNOS/HSP90 complex is increased in response to eNOS-activating agonists in a manner that depends on HSP90 activity. In vitro binding assays with glutathione S-transferase fusion proteins that contain the alpha- or beta-subunit of sGC show that the sGC beta-subunit interacts directly with HSP90 and indirectly with eNOS. Confocal immunofluorescent studies confirm the subcellular colocalization of sGC and HSP90 in both endothelial and smooth muscle cells. Complex formation of sGC with HSP90 facilitates responses to NO donors in cultured cells (cGMP accumulation) as well as in anesthetized rats (hypotension). These complexes likely function to stabilize sGC as well as to provide directed intracellular transfer of NO from NOS to sGC, thus preventing inactivation of NO by superoxide anion and formation of peroxynitrite, which is a toxic molecule that has been implicated in the pathology of several vascular diseases.
authors.affiliation: Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912-2500, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Venema
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Venema
authors.forename: Hong
authors.initials: H
authors.lastname: Ju
authors.forename: M Brennan
authors.initials: MB
authors.lastname: Harris
authors.forename: Connie
authors.initials: C
authors.lastname: Snead
authors.forename: Tamas
authors.initials: T
authors.lastname: Jilling
authors.forename: Christiana
authors.initials: C
authors.lastname: Dimitropoulou
authors.forename: Michael E
authors.initials: ME
authors.lastname: Maragoudakis
authors.forename: John D
authors.initials: JD
authors.lastname: Catravas
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D016227:Benzoquinones; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D047029:Lactams, Macrocyclic; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009599:Nitroprusside / Q000494:pharmacology; D011809:Quinones / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D020030:Nitric Oxide Donors; D011809:Quinones; D009599:Nitroprusside; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D006162:Guanylate Cyclase; C001277:geldanamycin