| Structural highlights
Function
[TBK1_HUMAN] Serine/threonine kinase that plays an essential role in regulating inflammatory responses to foreign agents. Following activation of toll-like receptors by viral or bacterial components, associates with TRAF3 and TANK and phosphorylates interferon regulatory factors (IRFs) IRF3 and IRF7 as well as DDX3X. This activity allows subsequent homodimerization and nuclear translocation of the IRFs leading to transcriptional activation of pro-inflammatory and antiviral genes including IFN-alpha and IFN-beta. In order to establish such an antiviral state, TBK1 form several different complexes whose composition depends on the type of cell and cellular stimuli. Thus, several scaffolding molecules including FADD, TRADD, MAVS or SINTBAD can be recruited to the TBK1-containing-complexes. Under particular conditions, functions as a NF-kappa-B effector by phosphorylating NF-kappa-B inhibitor alpha/NFKBIA, IKBKB or RELA to translocate NF-Kappa-B to the nucleus. Restricts bacterial proliferation by phosphorylating the autophagy receptor OPTN/Optineurin on 'Ser-177', thus enhancing LC3 binding affinity and antibacterial autophagy. Attenuates retroviral budding by phosphorylating the endosomal sorting complex required for transport-I (ESCRT-I) subunit VPS37C. Phosphorylates and activates AKT1. Phosphorylates Borna disease virus (BDV) P protein.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Publication Abstract from PubMed
Chronic low-grade inflammation is a hallmark of obesity, which is a risk factor for the development of type 2 diabetes. The drug amlexanox inhibits IkappaB kinase epsilon (IKKepsilon) and TANK binding kinase 1 (TBK1) to promote energy expenditure and improve insulin sensitivity. Clinical studies have demonstrated efficacy in a subset of diabetic patients with underlying adipose tissue inflammation, albeit with moderate potency, necessitating the need for improved analogs. Herein we report crystal structures of TBK1 in complex with amlexanox and a series of analogs that modify its carboxylic acid moiety. Removal of the carboxylic acid or mutation of the adjacent Thr156 residue significantly reduces potency toward TBK1, whereas conversion to a short amide or ester nearly abolishes the inhibitory effects. IKKepsilon is less affected by these modifications, possibly due to variation in its hinge that allows for increased conformational plasticity. Installation of a tetrazole carboxylic acid bioisostere improved potency to 200 and 400 nM toward IKKepsilon and TBK1, respectively. Despite improvements in the in vitro potency, no analog produced a greater response in adipocytes than amlexanox, perhaps because of altered absorption and distribution. The structure-activity relationships and cocrystal structures described herein will aid in future structure-guided inhibitor development using the amlexanox pharmacophore for the treatment of obesity and type 2 diabetes.
Carboxylic Acid Derivatives of Amlexanox Display Enhanced Potency toward TBK1 and IKKepsilon and Reveal Mechanisms for Selective Inhibition.,Beyett TS, Gan X, Reilly SM, Chang L, Gomez AV, Saltiel AR, Showalter HD, Tesmer JJG Mol Pharmacol. 2018 Oct;94(4):1210-1219. doi: 10.1124/mol.118.112185. Epub 2018, Aug 6. PMID:30082428[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Tojima Y, Fujimoto A, Delhase M, Chen Y, Hatakeyama S, Nakayama K, Kaneko Y, Nimura Y, Motoyama N, Ikeda K, Karin M, Nakanishi M. NAK is an IkappaB kinase-activating kinase. Nature. 2000 Apr 13;404(6779):778-82. PMID:10783893 doi:10.1038/35008109
- ↑ Kishore N, Huynh QK, Mathialagan S, Hall T, Rouw S, Creely D, Lange G, Caroll J, Reitz B, Donnelly A, Boddupalli H, Combs RG, Kretzmer K, Tripp CS. IKK-i and TBK-1 are enzymatically distinct from the homologous enzyme IKK-2: comparative analysis of recombinant human IKK-i, TBK-1, and IKK-2. J Biol Chem. 2002 Apr 19;277(16):13840-7. Epub 2002 Feb 11. PMID:11839743 doi:10.1074/jbc.M110474200
- ↑ Fitzgerald KA, McWhirter SM, Faia KL, Rowe DC, Latz E, Golenbock DT, Coyle AJ, Liao SM, Maniatis T. IKKepsilon and TBK1 are essential components of the IRF3 signaling pathway. Nat Immunol. 2003 May;4(5):491-6. PMID:12692549 doi:10.1038/ni921
- ↑ Sharma S, tenOever BR, Grandvaux N, Zhou GP, Lin R, Hiscott J. Triggering the interferon antiviral response through an IKK-related pathway. Science. 2003 May 16;300(5622):1148-51. Epub 2003 Apr 17. PMID:12702806 doi:10.1126/science.1081315
- ↑ Mori M, Yoneyama M, Ito T, Takahashi K, Inagaki F, Fujita T. Identification of Ser-386 of interferon regulatory factor 3 as critical target for inducible phosphorylation that determines activation. J Biol Chem. 2004 Mar 12;279(11):9698-702. Epub 2003 Dec 31. PMID:14703513 doi:10.1074/jbc.M310616200
- ↑ Kuai J, Wooters J, Hall JP, Rao VR, Nickbarg E, Li B, Chatterjee-Kishore M, Qiu Y, Lin LL. NAK is recruited to the TNFR1 complex in a TNFalpha-dependent manner and mediates the production of RANTES: identification of endogenous TNFR-interacting proteins by a proteomic approach. J Biol Chem. 2004 Dec 17;279(51):53266-71. Epub 2004 Oct 13. PMID:15485837 doi:M411037200
- ↑ Buss H, Dorrie A, Schmitz ML, Hoffmann E, Resch K, Kracht M. Constitutive and interleukin-1-inducible phosphorylation of p65 NF-{kappa}B at serine 536 is mediated by multiple protein kinases including I{kappa}B kinase (IKK)-{alpha}, IKK{beta}, IKK{epsilon}, TRAF family member-associated (TANK)-binding kinase 1 (TBK1), and an unknown kinase and couples p65 to TATA-binding protein-associated factor II31-mediated interleukin-8 transcription. J Biol Chem. 2004 Dec 31;279(53):55633-43. Epub 2004 Oct 15. PMID:15489227 doi:10.1074/jbc.M409825200
- ↑ tenOever BR, Sharma S, Zou W, Sun Q, Grandvaux N, Julkunen I, Hemmi H, Yamamoto M, Akira S, Yeh WC, Lin R, Hiscott J. Activation of TBK1 and IKKvarepsilon kinases by vesicular stomatitis virus infection and the role of viral ribonucleoprotein in the development of interferon antiviral immunity. J Virol. 2004 Oct;78(19):10636-49. PMID:15367631 doi:10.1128/JVI.78.19.10636-10649.2004
- ↑ Soulat D, Burckstummer T, Westermayer S, Goncalves A, Bauch A, Stefanovic A, Hantschel O, Bennett KL, Decker T, Superti-Furga G. The DEAD-box helicase DDX3X is a critical component of the TANK-binding kinase 1-dependent innate immune response. EMBO J. 2008 Aug 6;27(15):2135-46. doi: 10.1038/emboj.2008.126. Epub 2008 Jun 26. PMID:18583960 doi:10.1038/emboj.2008.126
- ↑ Da Q, Yang X, Xu Y, Gao G, Cheng G, Tang H. TANK-binding kinase 1 attenuates PTAP-dependent retroviral budding through targeting endosomal sorting complex required for transport-I. J Immunol. 2011 Mar 1;186(5):3023-30. doi: 10.4049/jimmunol.1000262. Epub 2011, Jan 26. PMID:21270402 doi:10.4049/jimmunol.1000262
- ↑ Xie X, Zhang D, Zhao B, Lu MK, You M, Condorelli G, Wang CY, Guan KL. IkappaB kinase epsilon and TANK-binding kinase 1 activate AKT by direct phosphorylation. Proc Natl Acad Sci U S A. 2011 Apr 19;108(16):6474-9. doi:, 10.1073/pnas.1016132108. Epub 2011 Apr 4. PMID:21464307 doi:10.1073/pnas.1016132108
- ↑ Wild P, Farhan H, McEwan DG, Wagner S, Rogov VV, Brady NR, Richter B, Korac J, Waidmann O, Choudhary C, Dotsch V, Bumann D, Dikic I. Phosphorylation of the autophagy receptor optineurin restricts Salmonella growth. Science. 2011 Jul 8;333(6039):228-33. doi: 10.1126/science.1205405. Epub 2011 May, 26. PMID:21617041 doi:10.1126/science.1205405
- ↑ Clark K, Peggie M, Plater L, Sorcek RJ, Young ER, Madwed JB, Hough J, McIver EG, Cohen P. Novel cross-talk within the IKK family controls innate immunity. Biochem J. 2011 Feb 15;434(1):93-104. doi: 10.1042/BJ20101701. PMID:21138416 doi:10.1042/BJ20101701
- ↑ Beyett TS, Gan X, Reilly SM, Chang L, Gomez AV, Saltiel AR, Showalter HD, Tesmer JJG. Carboxylic Acid Derivatives of Amlexanox Display Enhanced Potency toward TBK1 and IKKepsilon and Reveal Mechanisms for Selective Inhibition. Mol Pharmacol. 2018 Oct;94(4):1210-1219. doi: 10.1124/mol.118.112185. Epub 2018, Aug 6. PMID:30082428 doi:http://dx.doi.org/10.1124/mol.118.112185
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