MLKL Compromises Plasma Membrane Integrity by Binding to Phosphatidylinositol Phosphates

• Published in: Cell reports (Cambridge) 2014-05, Vol.7 (4), p.971-981
• Main Authors: Dondelinger, Yves, Declercq, Wim, Montessuit, Sylvie, Roelandt, Ria, Goncalves, Amanda, Bruggeman, Inge, Hulpiau, Paco, Weber, Kathrin, Sehon, Clark A., Marquis, Robert W., Bertin, John, Gough, Peter J., Savvides, Savvas, Martinou, Jean-Claude, Bertrand, Mathieu J.M., Vandenabeele, Peter
• Format: Article
• Language: English
• Subjects: Cell Death - drug effects; Cell Death - physiology; Cell Line; Cell Membrane - enzymology; Cell Membrane - metabolism; HEK293 Cells; Humans; Liposomes - metabolism; Necrosis; Phosphatidylinositol Phosphates - metabolism; Phosphorylation; Protein Kinases - metabolism; Protein Kinases - pharmacology; Recombinant Proteins - pharmacology; Signal Transduction; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2014.04.026

Although mixed lineage kinase domain-like (MLKL) protein has emerged as a specific and crucial protein for necroptosis induction, how MLKL transduces the death signal remains poorly understood. Here, we demonstrate that the full four-helical bundle domain (4HBD) in the N-terminal region of MLKL is required and sufficient to induce its oligomerization and trigger cell death. Moreover, we found that a patch of positively charged amino acids on the surface of the 4HBD binds to phosphatidylinositol phosphates (PIPs) and allows recruitment of MLKL to the plasma membrane. Importantly, we found that recombinant MLKL, but not a mutant lacking these positive charges, induces leakage of PIP-containing liposomes as potently as BAX, supporting a model in which MLKL induces necroptosis by directly permeabilizing the plasma membrane. Accordingly, we found that inhibiting the formation of PI(5)P and PI(4,5)P2 specifically inhibits tumor necrosis factor (TNF)-mediated necroptosis but not apoptosis. [Display omitted] •The four-helical bundle domain of MLKL is sufficient for necroptosis induction•MLKL binds phosphatidylinositol phosphates via positive charges in the 4HBD•Recombinant MLKL induces leakage of PIP-containing liposomes•Inhibiting the formation of PI(5)P and PI(4,5)P2 inhibits TNF-mediated necroptosis Necroptosis is a caspase-independent form of cell death that contributes to the pathogenesis of several human diseases, including ischemia-reperfusion injury, sepsis, and viral infection. Although MLKL emerged as a specific and crucial protein for necroptosis induction, it remains poorly understood how MLKL transduces the death signal. Here, Dondelinger et al., demonstrate that MLKL is recruited to phosphatidylinositol phosphates in the plasma membrane by a positive patch in its four-helical bundle domain. Interestingly, their data suggest that MLKL is able to directly permeabilize membranes.