Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.

Lytic cell death including necroptosis and pyroptosis is induced by mixed lineage kinase domain-like protein (MLKL) phosphorylation and inflammatory caspase specific cleavage Gasdermins in higher mammals, respectively. In this study, we identified a novel MLKL homolog containing a tetrapeptide recog...

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Main Authors: Kaiyu Chen, Sikou Shen, Zhimeng Lv, Ming Guo, Yina Shao, Chenghua Li
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-03-01
Series:PLoS Pathogens
Online Access:https://doi.org/10.1371/journal.ppat.1012991
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author Kaiyu Chen
Sikou Shen
Zhimeng Lv
Ming Guo
Yina Shao
Chenghua Li
author_facet Kaiyu Chen
Sikou Shen
Zhimeng Lv
Ming Guo
Yina Shao
Chenghua Li
author_sort Kaiyu Chen
collection DOAJ
description Lytic cell death including necroptosis and pyroptosis is induced by mixed lineage kinase domain-like protein (MLKL) phosphorylation and inflammatory caspase specific cleavage Gasdermins in higher mammals, respectively. In this study, we identified a novel MLKL homolog containing a tetrapeptide recognition motif (14-LVAD-17) of inflammatory caspase from Apostichopus japonicus,which was absent of Gasdermins member by genome screening. Functional analysis revealed that AjMLKL was involved in the regulation of Vibrio splendidus AJ01 infection induced lytic coelomocyte death in a cleavage-dependent manner, but not through RIPK3-dependent phosphorylation as mammals. Mechanistically, the activated form of cysteine-aspartic specific proteases-1 (AjCASP-1) bound to the tetrapeptide site of AjMLKL and cleaved it at Asp17. Cleaved AjMLKL18-491 displayed higher binding affinities towards phosphatidylinositol phosphate and cardiolipin compared to those of un-cleaved form. In addition, cleaved AjMLKL18-491 exerted stronger ability in disrupting the membrane integrity of liposome. More importantly, AjMLKL18-491 caused a large non-selective ionic coelomocyte pore and could directly kill the invasive AJ01. Moreover, activation of inflammatory AjCASP-1 was further found to be dependent on forming an inflammasome-like complex via CASc domain of AjCASP-1 and the N-terminal Ig domains of internalized AjNLRC4. All our results proved first evidence that lytic cell death was activated through MLKL cleavage, not MLKL phosphorylation in echinoderm, which offered insights into the functional, evolutionary mechanisms of lytic cell death in invertebrates.
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spelling doaj-art-203ccfc567324dca85d6d6c878e4034c2025-08-20T03:13:39ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742025-03-01213e101299110.1371/journal.ppat.1012991Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.Kaiyu ChenSikou ShenZhimeng LvMing GuoYina ShaoChenghua LiLytic cell death including necroptosis and pyroptosis is induced by mixed lineage kinase domain-like protein (MLKL) phosphorylation and inflammatory caspase specific cleavage Gasdermins in higher mammals, respectively. In this study, we identified a novel MLKL homolog containing a tetrapeptide recognition motif (14-LVAD-17) of inflammatory caspase from Apostichopus japonicus,which was absent of Gasdermins member by genome screening. Functional analysis revealed that AjMLKL was involved in the regulation of Vibrio splendidus AJ01 infection induced lytic coelomocyte death in a cleavage-dependent manner, but not through RIPK3-dependent phosphorylation as mammals. Mechanistically, the activated form of cysteine-aspartic specific proteases-1 (AjCASP-1) bound to the tetrapeptide site of AjMLKL and cleaved it at Asp17. Cleaved AjMLKL18-491 displayed higher binding affinities towards phosphatidylinositol phosphate and cardiolipin compared to those of un-cleaved form. In addition, cleaved AjMLKL18-491 exerted stronger ability in disrupting the membrane integrity of liposome. More importantly, AjMLKL18-491 caused a large non-selective ionic coelomocyte pore and could directly kill the invasive AJ01. Moreover, activation of inflammatory AjCASP-1 was further found to be dependent on forming an inflammasome-like complex via CASc domain of AjCASP-1 and the N-terminal Ig domains of internalized AjNLRC4. All our results proved first evidence that lytic cell death was activated through MLKL cleavage, not MLKL phosphorylation in echinoderm, which offered insights into the functional, evolutionary mechanisms of lytic cell death in invertebrates.https://doi.org/10.1371/journal.ppat.1012991
spellingShingle Kaiyu Chen
Sikou Shen
Zhimeng Lv
Ming Guo
Yina Shao
Chenghua Li
Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
PLoS Pathogens
title Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
title_full Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
title_fullStr Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
title_full_unstemmed Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
title_short Lytic coelomocyte death is tuned by cleavage but not phosphorylation of MLKL in echinoderms.
title_sort lytic coelomocyte death is tuned by cleavage but not phosphorylation of mlkl in echinoderms
url https://doi.org/10.1371/journal.ppat.1012991
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