title: The MLKL Channel in Necroptosis Is an Octamer Formed by Tetramers in a Dyadic Process.
abstract: Oligomerization of the mixed-lineage kinase domain-like protein (MLKL) is essential for its cation channel function in necroptosis. Here we show that the MLKL channel is an octamer comprising two previously identified tetramers most likely in their side-by-side position. Intermolecule disulfide bonds are present in the tetramer but are not required for octamer assembly and necroptosis. MLKL forms oligomers in the necrosome and is then released from the necrosome before or during its membrane translocation. We identified two MLKL mutants that could not oligomerize into octamers, although they formed a tetramer, and also, one MLKL mutant could spontaneously form a disulfide bond-linked octamer. Subsequent analysis revealed that the tetramers fail to translocate to the plasma membrane and that the MLKL octamer formation depends on α-helices 4 and 5. While MLKL could be detected from outside the cells, its N- and C-terminal ends could not be detected, indicating that the MLKL octamer spans across the plasma membrane, leaving its N and C termini inside the cell. These data allowed us to propose a 180° symmetry model of the MLKL octamer and conclude that the fully assembled MLKL octamers, but not the previously described tetramers, act as effectors of necroptosis.
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Deli
authors.initials: D
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Xinru
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Zi-An
authors.initials: ZA
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: He
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Jin-Gen
authors.initials: JG
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Wenke
authors.initials: W
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Yongqun
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, China jhan@xmu.edu.cn.
authors.forename: Jiahuai
authors.initials: J
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008954:Models, Biological; D009336:Necrosis; D011485:Protein Binding / Q000187:drug effects; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism*; D055503:Protein Multimerization / Q000187:drug effects; D017433:Protein Structure, Secondary; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D004220:Disulfides; D014409:Tumor Necrosis Factor-alpha; C570693:MLKL protein, human; C570694:MLKL protein, mouse; D011494:Protein Kinases
keywords: MLKL; channel; necroptosis; octamer