MLKL forms disulfide bond-dependent amyloid-like polymers to induce necroptosis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 114; no. 36; pp. E7450 - E7459
• Main Authors: Liu, Shuzhen, Liu, Hua, Johnston, Andrea, Hanna-Addams, Sarah, Reynoso, Eduardo, Xiang, Yougui, Wang, Zhigao
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05.09.2017
• Series: PNAS Plus
• Subjects: Amyloid - metabolism; Amyloidogenic Proteins - metabolism; Animals; Apoptosis - drug effects; Biological Sciences; Cell death; Cell Death - drug effects; Cell Line, Tumor; Disulfides - metabolism; Electron microscopes; Electron microscopy; Endopeptidase K; Fibers; HeLa Cells; HT29 Cells; Humans; Kinases; MAP kinase; Mice; Mutants; Necroptosis; Necrosis - chemically induced; Necrosis - metabolism; PNAS Plus; Polymers; Polymers - pharmacology; Protein kinase; Protein Kinases - metabolism; Proteinase; Receptor-Interacting Protein Serine-Threonine Kinases - metabolism; Studies; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α; β-Amyloid; polymer; disulfide bond; MLKL; amyloid-like; necroptosis
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1707531114

Mixed-lineage kinase domain-like protein (MLKL) is essential for TNF-α–induced necroptosis. How MLKL promotes cell death is still under debate. Here we report that MLKL forms SDS-resistant, disulfide bond-dependent polymers during necroptosis in both human and mouse cells. MLKL polymers are independent of receptor-interacting protein kinase 1 and 3 (RIPK1/RIPK3) fibers. Large MLKL polymers are more than 2 million Da and are resistant to proteinase K digestion. MLKL polymers are fibers 5 nm in diameter under electron microscopy. Furthermore, the recombinant N-terminal domain of MLKL forms amyloid-like fibers and binds Congo red dye. MLKL mutants that cannot form polymers also fail to induce necroptosis efficiently. Finally, the compound necrosulfonamide conjugates cysteine 86 of human MLKL and blocks MLKL polymer formation and subsequent cell death. These results demonstrate that disulfide bond-dependent, amyloid-like MLKL polymers are necessary and sufficient to induce necroptosis.