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,...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 preferential y to Mg2+rather than Ca2+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 Mg2+-preferred permeability and five transmembrane segment topology distinguish MLKL from previously identified Mg2+-permeable channels and thus establish MLKL as a novel class of cation channels.展开更多
Intense inflammatory pain caused by urate crystals in joints and other tissues is a major symptom of gout.Among therapy drugs that lower urate,benzbromarone(BBR),an inhibitor of urate transporters,is widely used becau...Intense inflammatory pain caused by urate crystals in joints and other tissues is a major symptom of gout.Among therapy drugs that lower urate,benzbromarone(BBR),an inhibitor of urate transporters,is widely used because it is well tolerated and highly effective.We demonstrate that BBR is also an activator of voltage-gated KCNQ potassium channels.In cultured recombinant cells,BBR exhibited significant potentiation effects on KCNQ channels comparable to previously reported classical activators.In native dorsal root ganglion neurons,BBR effectively overcame the suppression of KCNQ currents,and the resultant neuronal hyperexcitability caused by inflammatory mediators,such as bradykinin(BK).Benzbromarone consistently attenuates BK-,formalin-,or monosodium urate-induced inflammatory pain in rat and mouse models.Notably,the analgesic effects of BBR are largely mediated through peripheral and not through central KCNQ channels,an observation supported both by pharmacokinetic studies and in vivo experiments.Moreover,multiple residues in the superficial part of the voltage sensing domain of KCNQ channels were identified critical for the potentiation activity of BBR by a molecular determinant investigation.Our data indicate that activation of peripheral KCNQ channels mediates the pain relief effects of BBR,potentially providing a new strategy for the development of more effective therapies for gout.展开更多
文摘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 preferential y to Mg2+rather than Ca2+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 Mg2+-preferred permeability and five transmembrane segment topology distinguish MLKL from previously identified Mg2+-permeable channels and thus establish MLKL as a novel class of cation channels.
文摘Intense inflammatory pain caused by urate crystals in joints and other tissues is a major symptom of gout.Among therapy drugs that lower urate,benzbromarone(BBR),an inhibitor of urate transporters,is widely used because it is well tolerated and highly effective.We demonstrate that BBR is also an activator of voltage-gated KCNQ potassium channels.In cultured recombinant cells,BBR exhibited significant potentiation effects on KCNQ channels comparable to previously reported classical activators.In native dorsal root ganglion neurons,BBR effectively overcame the suppression of KCNQ currents,and the resultant neuronal hyperexcitability caused by inflammatory mediators,such as bradykinin(BK).Benzbromarone consistently attenuates BK-,formalin-,or monosodium urate-induced inflammatory pain in rat and mouse models.Notably,the analgesic effects of BBR are largely mediated through peripheral and not through central KCNQ channels,an observation supported both by pharmacokinetic studies and in vivo experiments.Moreover,multiple residues in the superficial part of the voltage sensing domain of KCNQ channels were identified critical for the potentiation activity of BBR by a molecular determinant investigation.Our data indicate that activation of peripheral KCNQ channels mediates the pain relief effects of BBR,potentially providing a new strategy for the development of more effective therapies for gout.
