title: Inhibitor-κB kinase attenuates Hsp90-dependent endothelial nitric oxide synthase function in vascular endothelial cells.
abstract: Endothelial nitric oxide (NO) synthase (eNOS) is the predominant isoform that generates NO in the blood vessels. Many different regulators, including heat shock protein 90 (Hsp90), govern eNOS function. Hsp90-dependent phosphorylation of eNOS is a critical event that determines eNOS activity. In our earlier study we demonstrated an inhibitor-κB kinase-β (IKKβ)-Hsp90 interaction in a high-glucose environment. In the present study we further define the putative binding domain of IKKβ on Hsp90. Interestingly, IKKβ binds to the middle domain of Hsp90, which has been shown to interact with eNOS to stimulate its activity. This new finding suggests a tighter regulation of eNOS activity than was previously assumed. Furthermore, addition of purified recombinant IKKβ to the eNOS-Hsp90 complex reduces the eNOS-Hsp90 interaction and eNOS activity, indicating a competition for Hsp90 between eNOS and IKKβ. The pathophysiological relevance of the IKKβ-Hsp90 interaction has also been demonstrated using in vitro vascular endothelial growth factor-mediated signaling and an Ins2(Akita) in vivo model. Our study further defines the preferential involvement of α- vs. β-isoforms of Hsp90 in the IKKβ-eNOS-Hsp90 interaction, even though both Hsp90α and Hsp90β stimulate NO production. These studies not only reinforce the significance of maintaining a homeostatic balance of eNOS and IKKβ within the cell system that regulates NO production, but they also confirm that the IKKβ-Hsp90 interaction is favored in a high-glucose environment, leading to impairment of the eNOS-Hsp90 interaction, which contributes to endothelial dysfunction and vascular complications in diabetes.
authors: Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas; mohan@uthscsa.edu.
authors: Mohan
authors: M
authors: Natarajan
authors: Department of Molecular Biology, Cancer Center Institute, Warsaw, Poland;
authors: Ryszard
authors: R
authors: Konopinski
authors: Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas;
authors: Manickam
authors: M
authors: Krishnan
authors: Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas;
authors: Linda
authors: L
authors: Roman
authors: Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas; and.
authors: Alakesh
authors: A
authors: Bera
authors: Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas;
authors: Zheng
authors: Z
authors: Hongying
authors: South Texas Veterans Health System, San Antonio, Texas.
authors: Samy L
authors: SL
authors: Habib
authors: Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas;
authors: Sumathy
authors: S
authors: Mohan
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D001665:Binding Sites; D002417:Cattle; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000473:pathology; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D018841:HSP90 Heat-Shock Proteins; C533585:HSP90AA2P protein, human; C493165:HSP90AB1 protein, human; C561967:Ins2 protein, mouse; D007328:Insulin; D034741:RNA, Small Interfering; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D051550:I-kappa B Kinase; D005947:Glucose
keywords: endothelial cells; endothelial nitric oxide synthase function; high glucose; inhibitor-κB kinase-β; nitric oxide
references: Mol Cell. 2002 Feb;9(2):401-10
references: 11864612
references: Am J Physiol Regul Integr Comp Physiol. 2003 Jan;284(1):R1-12
references: 12482742
references: J Cell Sci. 2003 Sep 15;116(Pt 18):3721-8
references: 12890756
references: Oncogene. 2004 Jul 8;23(31):5378-86
references: 15077173
references: J Biol Chem. 1994 Jan 14;269(2):981-5
references: 7507114
references: Methods Enzymol. 1994;233:250-8
references: 7516999
references: Proc Natl Acad Sci U S A. 1995 Aug 29;92(18):8428-32
references: 7545302
references: Biochem Biophys Res Commun. 1996 Feb 15;219(2):359-65
references: 8604992
references: J Cell Biochem. 2005 Jan 1;94(1):194-201
references: 15526284
references: J Immunol. 2005 Jan 1;174(1):384-94
references: 15611262
references: J Mol Cell Cardiol. 2005 Aug;39(2):327-34
references: 15978611
references: Circ Res. 2005 Nov 11;97(10):975-82
references: 16224066
references: Genomics. 2005 Dec;86(6):627-37
references: 16269234
references: Exp Mol Med. 2006 Feb 28;38(1):63-71
references: 16520554
references: Circulation. 2006 Apr 4;113(13):1708-14
references: 16585403
references: Carcinogenesis. 2007 Jan;28(1):71-80
references: 16774932
references: Am J Physiol Cell Physiol. 2007 Jan;292(1):C362-71
references: 16914532
references: Biochemistry. 2007 Feb 6;46(5):1320-8
references: 17260961
references: J Biol Chem. 2007 Mar 30;282(13):9364-71
references: 17202141
references: FEBS J. 2007 Sep;274(17):4453-63
references: 17681020
references: Arterioscler Thromb Vasc Biol. 2008 Jan;28(1):105-11
references: 17975117
references: Biochem Cell Biol. 2008 Feb;86(1):37-45
references: 18364744
references: Am J Physiol Cell Physiol. 2009 Jan;296(1):C182-92
references: 18945937
references: Am J Physiol Heart Circ Physiol. 2009 Jun;296(6):H1850-8
references: 19363130
references: Cell Physiol Biochem. 2010;26(4-5):657-68
references: 21063103
references: Biomed J. 2013 May-Jun;36(3):106-17
references: 23806880
references: Circ Res. 2002 May 3;90(8):838-41
references: 11988482
references: Endocrine. 2014 Mar;45(2):263-70
references: 23640371
references: Circ Res. 2002 May 3;90(8):866-73
references: 11988487
references: Cell Biol Int. 2003;27(1):47-52
references: 12713799