scholarly journals Site-specific ubiquitination of MLKL targets it to endosomes and targets Listeria and Yersinia to the lysosomes

2022 ◽  
Author(s):  
Seongmin Yoon ◽  
Konstantin Bogdanov ◽  
David Wallach
Keyword(s):  
Cell Death ◽  
Defense Mechanisms ◽  
Kinase Domain ◽  
Intracellular Bacteria ◽  
Endosomal Trafficking ◽  
Polyubiquitin Chains ◽  
Mixed Lineage Kinase ◽  
Lysine Residues ◽  
Covalent Modifications ◽  
Bacterial Yield

AbstractPhosphorylation of the pseudokinase mixed lineage kinase domain-like protein (MLKL) by the protein kinase RIPK3 targets MLKL to the cell membrane, where it triggers necroptotic cell death. We report that conjugation of K63-linked polyubiquitin chains to distinct lysine residues in the N-terminal HeLo domain of phosphorylated MLKL (facilitated by the ubiquitin ligase ITCH that binds MLKL via a WW domain) targets MLKL instead to endosomes. This results in the release of phosphorylated MLKL within extracellular vesicles. It also prompts enhanced endosomal trafficking of intracellular bacteria such as Listeria monocytogenes and Yersinia enterocolitica to the lysosomes, resulting in decreased bacterial yield. Thus, MLKL can be directed by specific covalent modifications to differing subcellular sites, whence it signals either for cell death or for non-deadly defense mechanisms.

scholarly journals Oligomerization-driven MLKL ubiquitylation antagonises necroptosis

2021 ◽  
Author(s):  
Zikou Liu ◽  
Laura Francesca Dagley ◽  
Kristy Lynn Shield-Artin ◽  
Samuel Nicholas Young ◽  
Aleksandra Bankovacki ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Protein Kinase ◽  
Kinase Domain ◽  
Membrane Disruption ◽  
Fusion Strategy ◽  
Mixed Lineage Kinase ◽  
Independent Form ◽  
Lysine Residues ◽  
Kinetic Regulation

Mixed lineage kinase domain-like (MLKL) is the executioner in the caspase-independent form of programmed cell death called necroptosis. Receptor Interacting serine/threonine Protein Kinase 3 (RIPK3) phosphorylates MLKL, triggering MLKL oligomerization, membrane translocation and membrane disruption. MLKL also undergoes ubiquitylation during necroptosis, yet neither the mechanism nor significance of this event have been demonstrated. Here we show that necroptosis-specific, multi-mono-ubiquitylation of MLKL occurs following its activation and oligomerization. Ubiquitylated MLKL accumulates in a digitonin insoluble cell fraction comprising plasma/organellar membranes and protein aggregates. This ubiquitylated form is diminished by a plasma membrane located deubiquitylating enzyme. MLKL is ubiquitylated on at least 4 separate lysine residues once oligomerized, and this correlates with proteasome- and lysosome- dependent turnover. Using a MLKL-DUB fusion strategy, we show that constitutive removal of ubiquitin from MLKL licenses MLKL auto-activity independent of necroptosis signalling in mouse and human cells. Therefore, besides its role in the kinetic regulation of MLKL-induced death following an exogenous necroptotic stimulus, ubiquitylation also contributes to the restraint of basal levels of activated MLKL to avoid errant cell death.

scholarly journals Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death

2016 ◽  
Vol 36 (1) ◽  
Author(s):  
Katja Hrovat Arnež ◽  
Michaela Kindlova ◽  
Nilesh J. Bokil ◽  
James M. Murphy ◽  
Matthew J. Sweet ◽  
...  
Keyword(s):  
Cell Death ◽  
Human Monocyte ◽  
Kinase Domain ◽  
Terminal Region ◽  
Activation Loop ◽  
Phosphorylation Sites ◽  
Mixed Lineage Kinase

We show that mixed lineage kinase domain-like (MLKL) isoform 2, which lacks the pseudokinase domain and activation loop phosphorylation sites, is a more potent activator of cell death compared with MLKL isoform 1. Both MLKL isoforms are expressed in human monocyte-derived macrophages.

scholarly journals Translocation of mixed lineage kinase domain-like protein to plasma membrane leads to necrotic cell death

Cell Research ◽  
2013 ◽  
Vol 24 (1) ◽  
pp. 105-121 ◽  
Author(s):  
Xin Chen ◽  
Wenjuan Li ◽  
Junming Ren ◽  
Deli Huang ◽  
Wan-ting He ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Kinase Domain ◽  
Necrotic Cell Death ◽  
Necrotic Cell ◽  
Mixed Lineage Kinase

scholarly journals Elevated Serum Levels of Mixed Lineage Kinase Domain-Like Protein Predict Survival of Patients during Intensive Care Unit Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mihael Vucur ◽  
Christoph Roderburg ◽  
Lukas Kaiser ◽  
Anne Theres Schneider ◽  
Sanchari Roy ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Cell Death ◽  
Intensive Care ◽  
Critical Illness ◽  
Critically Ill Patients ◽  
Serum Levels ◽  
Kinase Domain ◽  
Healthy Controls ◽  
Mixed Lineage Kinase ◽  
Icu Treatment

Mixed lineage kinase domain-like (MLKL), a crucial regulator of necroptotic cell death, was shown to play a role in inflammatory diseases. However, its role as a biomarker in critical illness and sepsis is currently unknown. We analyzed serum levels of MLKL in 136 critically ill patients at admission to the intensive care unit (ICU) and after three days of ICU treatment. Results were compared with 36 healthy controls and correlated with clinical and laboratory patients’ data. MLKL serum levels of critically ill patients at admission to the ICU were similar compared to healthy controls. At ICU admission, MLKL serum concentrations were independent of disease severity, presence of sepsis, and etiology of critical illness. In contrast, median serum levels of MLKL after three days of ICU treatment were significantly lower compared to those at admission to the ICU. While serum levels of MLKL at admission were not predictive for short-term survival during ICU treatment, elevated MLKL concentrations at day three were an independent negative predictor of patients’ ICU survival. Thus, elevated MLKL levels after three days of ICU treatment were predictive for patients’ mortality, indicating that sustained deregulated cell death is associated with an adverse prognosis in critical illness.

scholarly journals Plant mixed lineage kinase domain-like proteins limit biotrophic pathogen growth

2019 ◽  
Author(s):  
Lisa Mahdi ◽  
Menghang Huang ◽  
Xiaoxiao Zhang ◽  
Ryohei Thomas Nakano ◽  
Leïla Brulé Kopp ◽  
...  
Keyword(s):  
Cell Death ◽  
Host Cell ◽  
Kinase Domain ◽  
Protein Family ◽  
Mixed Lineage Kinase ◽  
Helical Bundles ◽  
Cryo Electron Microscopy ◽  
Host Cell Death ◽  
A Cell ◽  
Immunity Mechanism

AbstractMixed lineage kinase domain-like (MLKL) protein mediates necroptotic cell death in vertebrates. We report here the discovery of a conserved protein family across seed plants that is structurally homologous to vertebrate MLKL. TheArabidopsis thalianagenome encodes three MLKLs with overlapping functions in limiting growth of obligate biotrophic fungal and oomycete pathogens. Although displaying a cell death activity mediated by N-terminal helical bundles, termed HeLo domain,AtMLKL-dependent immunity can be separated from host cell death. Cryo-electron microscopy structures ofAtMLKLs reveal a tetrameric configuration, in which the pseudokinase domain and brace region bury the HeLo-domains, indicative of an auto-repressed complex. We also show the association of twoAtMLKLs with microtubules. These findings, coupled with resistance-enhancing activity and altered microtubule association of a phosphomimetic mutation in the pseudokinase domain ofAtMLKL1, point to a cell death-independent immunity mechanism.One Sentence SummaryPlants have a protein family that is structurally homologous to vertebrate mixed lineage kinase domain-like protein, which induces necroptotic cell death, but these plant proteins can confer immunity without host cell death.

scholarly journals RIPK3-Dependent Necroptosis Is Induced and Restricts Viral Replication in Human Astrocytes Infected With Zika Virus

2021 ◽  
Vol 11 ◽  
Author(s):  
Chunxia Wen ◽  
Yufeng Yu ◽  
Chengfeng Gao ◽  
Xian Qi ◽  
Carol J. Cardona ◽  
...  
Keyword(s):  
Cell Death ◽  
Viral Replication ◽  
Zika Virus ◽  
Developmental Disorders ◽  
Viral Disease ◽  
Kinase Domain ◽  
Zikv Infection ◽  
Mixed Lineage Kinase ◽  
Disease Outcomes ◽  
Human Astrocytes

Apoptosis, pyroptosis and necroptosis are regulated processes of cell death which can be crucial for viral disease outcomes in hosts because of their effects on viral pathogenicity and host resistance. Zika virus (ZIKV) is a mosquito-borne flavivirus, which infects humans and can cause neurological disorders. Neural developmental disorders and microcephaly could occur in infected fetuses. Several types of nervous cells have been reported to be susceptible to ZIKV infection. Human astrocytes play important roles in the nutritional support and defense of neurons. In this study, we show that human astrocytes are susceptible to ZIKV infection and undergo progressive cell death after infection. In infected astrocytes we detected no cleavage or activation of pro-caspase-3 and pro-caspase-1. Apoptotic substrates and increased secretion of interleukin (IL)-1β or IL-18 were not detected, either. These ruled out the occurrence of apoptosis or pyroptosis in ZIKV-infected astrocytes. We detected, however, an increase of phosphorylated receptor-interacting serine/threonine-protein kinase (RIPK)1, RIPK3, and mixed lineage kinase domain-like (MLKL) protein, indicating that programmed necrosis, or necroptosis, was induced in infected astrocytes. The phosphorylation and cell death were inhibited in cells pre-treated with GSK’872, an inhibitor of RIPK3, while inhibition of RIPK1 with an inhibitor, Necrostatin-1, had no effect, suggesting that ZIKV-induced necroptosis was RIPK1-independent in astrocytes. Consistent with this finding, the inhibition of RIPK1 had no effect on the phosphorylation of MLKL. We showed evidence that MLKL phosphorylation was RIPK3-dependent and ZBP-1, which could stimulate RIPK3, was upregulated in ZIKV-infected astrocytes. Finally, we demonstrated that in GSK’872-pre-treated astrocytes, viral replication increased significantly, which indicates that necroptosis may be protective against viral replication in astrocytes. Our finding that astrocytes uniquely underwent necroptosis in response to ZIKV infection provides insight and helps us better understand the viral pathogenesis in the ZIKV-infected central nervous system.

scholarly journals RIP1, RIP3, and MLKL Contribute to Cell Death Caused by Clostridium perfringens Enterotoxin

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Archana Shrestha ◽  
Iman Mehdizadeh Gohari ◽  
Bruce A. McClane
Keyword(s):  
Cell Death ◽  
Clostridium Perfringens ◽  
Vero Cells ◽  
Kinase Domain ◽  
Content Type ◽  
Mixed Lineage Kinase ◽  
Human Enterocyte ◽  
Induced Apoptosis ◽  
Apoptosis And Necrosis ◽  
Calpain Inhibitors

ABSTRACT Clostridium perfringens type F strains cause gastrointestinal disease when they produce a pore-forming toxin named C. perfringens enterotoxin (CPE). In human enterocyte-like Caco-2 cells, low CPE concentrations cause caspase-3-dependent apoptosis, while high CPE concentrations cause necrosis. Since necrosis or apoptosis sometimes involves receptor-interacting serine/threonine-protein kinase-1 or 3 (RIP1 or RIP3), this study examined whether those kinases are important for CPE-induced apoptosis or necrosis. Highly specific RIP1 or RIP3 inhibitors reduced both CPE-induced apoptosis and necrosis in Caco-2 cells. Those findings suggested that the form of necrosis induced by treating Caco-2 cells with high CPE concentrations involves necroptosis, which was confirmed when high, but not low, CPE concentrations were shown to induce oligomerization of mixed-lineage kinase domain-like pseudokinase (MLKL), a key late step in necroptosis. Furthermore, an MLKL oligomerization inhibitor reduced cell death caused by high, but not low, CPE concentrations. Supporting RIP1 and RIP3 involvement in CPE-induced necroptosis, inhibitors of those kinases also reduced MLKL oligomerization during treatment with high CPE concentrations. Calpain inhibitors similarly blocked MLKL oligomerization induced by high CPE concentrations, implicating calpain activation as a key intermediate in initiating CPE-induced necroptosis. In two other CPE-sensitive cell lines, i.e., Vero cells and human enterocyte-like T84 cells, low CPE concentrations also caused primarily apoptosis/late apoptosis, while high CPE concentrations mainly induced necroptosis. Collectively, these results establish that high, but not low, CPE concentrations cause necroptosis and suggest that RIP1, RIP3, MLKL, or calpain inhibitors can be explored as potential therapeutics against CPE effects in vivo. IMPORTANCE C. perfringens type F strains are a common cause of food poisoning and antibiotic-associated diarrhea. Type F strain virulence requires production of C. perfringens enterotoxin (CPE). In Caco-2 cells, high CPE concentrations cause necrosis while low enterotoxin concentrations induce apoptosis. The current study determined that receptor-interacting serine/threonine-protein kinases 1 and 3 are involved in both CPE-induced apoptosis and necrosis in Caco-2 cells, while mixed-lineage kinase domain-like pseudokinase (MLKL) oligomerization is involved in CPE-induced necrosis, thereby indicating that this form of CPE-induced cell death involves necroptosis. High CPE concentrations also caused necroptosis in T84 and Vero cells. Calpain activation was identified as a key intermediate for CPE-induced necroptosis. These results suggest inhibitors of RIP1, RIP3, MLKL oligomerization, or calpain are useful therapeutics against CPE-mediated diseases.

Location, location, location: A compartmentalized view of TNF-induced necroptotic signaling

2021 ◽  
Vol 14 (668) ◽  
pp. eabc6178
Author(s):  
André L. Samson ◽  
Sarah E. Garnish ◽  
Joanne M. Hildebrand ◽  
James M. Murphy
Keyword(s):  
Cell Death ◽  
Protein Kinases ◽  
Host Defense ◽  
Kinase Domain ◽  
Dependent Manner ◽  
Cell Type ◽  
Mixed Lineage Kinase ◽  
Cell Death Pathway ◽  
Subcellular Compartmentalization ◽  
High Degree

Necroptosis is a lytic, proinflammatory cell death pathway, which has been implicated in host defense and, when dysregulated, the pathology of many human diseases. The central mediators of this pathway are the receptor-interacting serine/threonine protein kinases RIPK1 and RIPK3 and the terminal executioner, the pseudokinase mixed lineage kinase domain–like (MLKL). Here, we review the chronology of signaling along the RIPK1-RIPK3-MLKL axis and highlight how the subcellular compartmentalization of signaling events controls the initiation and execution of necroptosis. We propose that a network of modulators surrounds the necroptotic signaling core and that this network, rather than acting universally, tunes necroptosis in a context-, cell type–, and species-dependent manner. Such a high degree of mechanistic flexibility is likely an important property that helps necroptosis operate as a robust, emergency form of cell death.

scholarly journals Post-translational control of RIPK3 and MLKL mediated necroptotic cell death

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 1297 ◽  
Author(s):  
James M. Murphy ◽  
James E. Vince
Keyword(s):  
Cell Death ◽  
Translational Control ◽  
Kinase Domain ◽  
Current Evidence ◽  
Deubiquitinating Enzymes ◽  
Critical Function ◽  
Interacting Protein ◽  
Mixed Lineage Kinase ◽  
Microbial Infections ◽  
Cell Death Mechanisms

Several programmed lytic and necrotic-like cell death mechanisms have now been uncovered, including the recently described receptor interacting protein kinase-3 (RIPK3)-mixed lineage kinase domain-like (MLKL)-dependent necroptosis pathway. Genetic experiments have shown that programmed necrosis, including necroptosis, can play a pivotal role in regulating host-resistance against microbial infections. Alternatively, excess or unwarranted necroptosis may be pathological in autoimmune and autoinflammatory diseases. This review highlights the recent advances in our understanding of the post-translational control of RIPK3-MLKL necroptotic signaling. We discuss the critical function of phosphorylation in the execution of necroptosis, and highlight the emerging regulatory roles for several ubiquitin ligases and deubiquitinating enzymes. Finally, based on current evidence, we discuss the potential mechanisms by which the essential, and possibly terminal, necroptotic effector, MLKL, triggers the disruption of cellular membranes to cause cell lysis.

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