title: MLKL forms cation channels.
abstract: The mixed lineage kinase domain-like (MLKL) protein is a key factor in tumor necrosis factor-induced necroptosis. Recent studies on necroptosis execution revealed a commitment role of MLKL in membrane disruption. However, our knowledge of how MLKL functions on membrane remains very limited. Here we demonstrate that MLKL forms cation channels that are permeable preferentially to Mg(2+) rather than Ca(2+) in the presence of Na(+) and K(+). Moreover, the N-terminal domain containing six helices (H1-H6) is sufficient to form channels. Using the substituted cysteine accessibility method, we further determine that helix H1, H2, H3, H5 and H6 are transmembrane segments, while H4 is located in the cytoplasm. Finally, MLKL-induced membrane depolarization and cell death exhibit a positive correlation to its channel activity. The Mg(2+)-preferred permeability and five transmembrane segment topology distinguish MLKL from previously identified Mg(2+)-permeable channels and thus establish MLKL as a novel class of cation channels.
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: Bingqing
authors.initials: B
authors.lastname: Xia
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: Sui
authors.initials: S
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Life Science and Technology, Shanghai Tech University, Shanghai 200031, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Hu
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: Peiyuan
authors.initials: P
authors.lastname: Chen
authors.affiliation: School of Life Science and Technology, Shanghai Tech University, Shanghai 200031, China.
authors.forename: Huayi
authors.initials: H
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: Zhaobing
authors.initials: Z
authors.lastname: Gao
mesh_terms: D002412:Cations; D016923:Cell Death; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary
chemical_list: D002412:Cations; D007473:Ion Channels; D008051:Lipid Bilayers; C570693:MLKL protein, human; D011494:Protein Kinases; D008274:Magnesium