title: NEK7 is an essential mediator of NLRP3 activation downstream of potassium efflux.
abstract: Inflammasomes are intracellular protein complexes that drive the activation of inflammatory caspases. So far, four inflammasomes involving NLRP1, NLRP3, NLRC4 and AIM2 have been described that recruit the common adaptor protein ASC to activate caspase-1, leading to the secretion of mature IL-1β and IL-18 proteins. The NLRP3 inflammasome has been implicated in the pathogenesis of several acquired inflammatory diseases as well as cryopyrin-associated periodic fever syndromes (CAPS) caused by inherited NLRP3 mutations. Potassium efflux is a common step that is essential for NLRP3 inflammasome activation induced by many stimuli. Despite extensive investigation, the molecular mechanism leading to NLRP3 activation in response to potassium efflux remains unknown. Here we report the identification of NEK7, a member of the family of mammalian NIMA-related kinases (NEK proteins), as an NLRP3-binding protein that acts downstream of potassium efflux to regulate NLRP3 oligomerization and activation. In the absence of NEK7, caspase-1 activation and IL-1β release were abrogated in response to signals that activate NLRP3, but not NLRC4 or AIM2 inflammasomes. NLRP3-activating stimuli promoted the NLRP3-NEK7 interaction in a process that was dependent on potassium efflux. NLRP3 associated with the catalytic domain of NEK7, but the catalytic activity of NEK7 was shown to be dispensable for activation of the NLRP3 inflammasome. Activated macrophages formed a high-molecular-mass NLRP3-NEK7 complex, which, along with ASC oligomerization and ASC speck formation, was abrogated in the absence of NEK7. NEK7 was required for macrophages containing the CAPS-associated NLRP3(R258W) activating mutation to activate caspase-1. Mouse chimaeras reconstituted with wild-type, Nek7(-/-) or Nlrp3(-/-) haematopoietic cells showed that NEK7 was required for NLRP3 inflammasome activation in vivo. These studies demonstrate that NEK7 is an essential protein that acts downstream of potassium efflux to mediate NLRP3 inflammasome assembly and activation.
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors.forename: Melody Y
authors.initials: MY
authors.lastname: Zeng
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.|The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Dahai
authors.initials: D
authors.lastname: Yang
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Benny
authors.initials: B
authors.lastname: Motro
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Núñez
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D053468:CARD Signaling Adaptor Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020170:Caspase 1 / Q000378:metabolism; D020134:Catalytic Domain; D002478:Cells, Cultured; D056587:Cryopyrin-Associated Periodic Syndromes / Q000235:genetics; D004789:Enzyme Activation; D057809:HEK293 Cells; D006801:Humans; D058847:Inflammasomes / Q000737:chemistry* / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D000072379:NIMA-Related Kinases; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D011188:Potassium / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D053468:CARD Signaling Adaptor Proteins; D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; C498534:Pycard protein, mouse; C512685:NEK7 protein, human; D000072379:NIMA-Related Kinases; C512686:Nek7 protein, mouse; D017346:Protein Serine-Threonine Kinases; D020170:Caspase 1; D011188:Potassium
references.citation: Nat Genet. 2001 Nov;29(3):301-5
references.pmid: 11687797
references.citation: Am J Hum Genet. 2002 Jul;71(1):198-203
references.pmid: 12032915
references.citation: Mol Cell. 2002 Aug;10(2):417-26
references.pmid: 12191486
references.citation: J Biol Chem. 2003 Sep 12;278(37):34897-909
references.pmid: 12840024
references.citation: Blood. 2004 Apr 1;103(7):2809-15
references.pmid: 14630794
references.citation: Nature. 1985 Dec 19-1986 Jan 1;318(6047):667-70
references.pmid: 4079980
references.citation: Cell. 1998 Feb 20;92(4):501-9
references.pmid: 9491891
references.citation: Nature. 2006 Mar 9;440(7081):233-6
references.pmid: 16407888
references.citation: Nature. 2006 Mar 9;440(7081):228-32
references.pmid: 16407890
references.citation: Immunity. 2006 Mar;24(3):317-27
references.pmid: 16546100
references.citation: Sci STKE. 2006 Jul 24;2006(345):pl4
references.pmid: 16868305
references.citation: FEBS Lett. 2006 Nov 27;580(27):6489-95
references.pmid: 17101132
references.citation: Biochem Biophys Res Commun. 2007 Aug 17;360(1):56-62
references.pmid: 17586473
references.citation: Cell Death Differ. 2007 Sep;14(9):1583-9
references.pmid: 17599094
references.citation: Annu Rev Immunol. 2009;27:229-65
references.pmid: 19302040
references.citation: Nat Immunol. 2016 Mar;17(3):250-8
references.pmid: 26642356
references.citation: Mol Cell Biol. 2009 Jul;29(14):3975-90
references.pmid: 19414596
references.citation: Immunity. 2009 Jun 19;30(6):860-74
references.pmid: 19501001
references.citation: J Biol Chem. 2016 Jan 1;291(1):103-9
references.pmid: 26553871
references.citation: Mol Cell. 2009 Nov 25;36(4):560-70
references.pmid: 19941817
references.citation: Nat Immunol. 2010 Feb;11(2):136-40
references.pmid: 20023662
references.citation: Immunity. 2010 Mar 26;32(3):379-91
references.pmid: 20303296
references.citation: Oncogene. 2010 Jul 15;29(28):4046-57
references.pmid: 20473324
references.citation: Annu Rev Immunol. 2011;29:707-35
references.pmid: 21219188
references.citation: Nature. 2011 Sep 29;477(7366):592-5
references.pmid: 21874021
references.citation: Nature. 2011 Nov 3;479(7371):117-21
references.pmid: 22002608
references.citation: Nat Immunol. 2012 Apr;13(4):333-42
references.pmid: 22430786
references.citation: J Cell Sci. 2012 Oct 1;125(Pt 19):4423-33
references.pmid: 23132929
references.citation: J Immunol. 2013 Jan 1;190(1):334-9
references.pmid: 23225887
references.citation: Biochim Biophys Acta. 2013 May;1833(5):1104-13
references.pmid: 23313050
references.citation: Immunity. 2013 Jun 27;38(6):1142-53
references.pmid: 23809161
references.citation: Science. 2013 Sep 13;341(6151):1246-9
references.pmid: 23887873
references.citation: Science. 2013 Sep 13;341(6151):1250-3
references.pmid: 24031018
references.citation: Nat Commun. 2015;6:7360
references.pmid: 26059659
references.citation: Nat Med. 2015 Jul;21(7):677-87
references.pmid: 26121197