title: The pseudokinase MLKL mediates necroptosis via a molecular switch mechanism.
abstract: Mixed lineage kinase domain-like (MLKL) is a component of the "necrosome," the multiprotein complex that triggers tumor necrosis factor (TNF)-induced cell death by necroptosis. To define the specific role and molecular mechanism of MLKL action, we generated MLKL-deficient mice and solved the crystal structure of MLKL. Although MLKL-deficient mice were viable and displayed no hematopoietic anomalies or other obvious pathology, cells derived from these animals were resistant to TNF-induced necroptosis unless MLKL expression was restored. Structurally, MLKL comprises a four-helical bundle tethered to the pseudokinase domain, which contains an unusual pseudoactive site. Although the pseudokinase domain binds ATP, it is catalytically inactive and its essential nonenzymatic role in necroptotic signaling is induced by receptor-interacting serine-threonine kinase 3 (RIPK3)-mediated phosphorylation. Structure-guided mutation of the MLKL pseudoactive site resulted in constitutive, RIPK3-independent necroptosis, demonstrating that modification of MLKL is essential for propagation of the necroptosis pathway downstream of RIPK3.
authors.affiliation: The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3050, Australia. Electronic address: jamesm@wehi.edu.au.
authors.forename: James M
authors.initials: JM
authors.lastname: Murphy
authors.forename: Peter E
authors.initials: PE
authors.lastname: Czabotar
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Hildebrand
authors.forename: Isabelle S
authors.initials: IS
authors.lastname: Lucet
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Zhang
authors.forename: Silvia
authors.initials: S
authors.lastname: Alvarez-Diaz
authors.forename: Rowena
authors.initials: R
authors.lastname: Lewis
authors.forename: Najoua
authors.initials: N
authors.lastname: Lalaoui
authors.forename: Donald
authors.initials: D
authors.lastname: Metcalf
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Webb
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Young
authors.forename: Leila N
authors.initials: LN
authors.lastname: Varghese
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Tannahill
authors.forename: Esme C
authors.initials: EC
authors.lastname: Hatchell
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Majewski
authors.forename: Toru
authors.initials: T
authors.lastname: Okamoto
authors.forename: Renwick C J
authors.initials: RC
authors.lastname: Dobson
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Hilton
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Babon
authors.forename: Nicos A
authors.initials: NA
authors.lastname: Nicola
authors.forename: Andreas
authors.initials: A
authors.lastname: Strasser
authors.forename: John
authors.initials: J
authors.lastname: Silke
authors.forename: Warren S
authors.initials: WS
authors.lastname: Alexander
mesh_terms: D000818:Animals; D017209:Apoptosis; D020134:Catalytic Domain; D002460:Cell Line; D018360:Crystallography, X-Ray; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009336:Necrosis; D010749:Phosphoprotein Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D048069:Tumor Necrosis Factors / Q000378:metabolism*
chemical_list: D048069:Tumor Necrosis Factors; C570694:MLKL protein, mouse; D011494:Protein Kinases; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C485615:Ripk3 protein, mouse; C570696:PGAM5 protein, mouse; D010749:Phosphoprotein Phosphatases; D010744:Phosphoric Monoester Hydrolases