scholarly journals A cytosolic heat shock protein 90 and cochaperone CDC37 complex is required for RIP3 activation during necroptosis

2015 ◽  
Vol 112 (16) ◽  
pp. 5017-5022 ◽  
Author(s):  
Dianrong Li ◽  
Tao Xu ◽  
Yang Cao ◽  
Huayi Wang ◽  
Lin Li ◽  
...  

Receptor-interacting protein kinase 3, RIP3, and a pseudokinase mixed lineage kinase-domain like protein, MLKL, constitute the core components of the necroptosis pathway, which causes programmed necrotic death in mammalian cells. Latent RIP3 in the cytosol is activated by several upstream signals including the related kinase RIP1, which transduces signals from the tumor necrosis factor (TNF) family of cytokines. We report here that RIP3 activation following the induction of necroptosis requires the activity of an HSP90 and CDC37 cochaperone complex. This complex physically associates with RIP3. Chemical inhibitors of HSP90 efficiently block necroptosis by preventing RIP3 activation. Cells with knocked down CDC37 were unable to respond to necroptosis stimuli. Moreover, an HSP90 inhibitor that is currently under clinical development as a cancer therapy was able to prevent systemic inflammatory response syndrome in rats treated with TNF-α. HSP90 and CDC37 cochaperone complex-mediated protein folding is thus an important part of the RIP3 activation process during necroptosis.

2017 ◽  
Vol 114 (36) ◽  
pp. E7450-E7459 ◽  
Author(s):  
Shuzhen Liu ◽  
Hua Liu ◽  
Andrea Johnston ◽  
Sarah Hanna-Addams ◽  
Eduardo Reynoso ◽  
...  

Mixed-lineage kinase domain-like protein (MLKL) is essential for TNF-α–induced necroptosis. How MLKL promotes cell death is still under debate. Here we report that MLKL forms SDS-resistant, disulfide bond-dependent polymers during necroptosis in both human and mouse cells. MLKL polymers are independent of receptor-interacting protein kinase 1 and 3 (RIPK1/RIPK3) fibers. Large MLKL polymers are more than 2 million Da and are resistant to proteinase K digestion. MLKL polymers are fibers 5 nm in diameter under electron microscopy. Furthermore, the recombinant N-terminal domain of MLKL forms amyloid-like fibers and binds Congo red dye. MLKL mutants that cannot form polymers also fail to induce necroptosis efficiently. Finally, the compound necrosulfonamide conjugates cysteine 86 of human MLKL and blocks MLKL polymer formation and subsequent cell death. These results demonstrate that disulfide bond-dependent, amyloid-like MLKL polymers are necessary and sufficient to induce necroptosis.


2018 ◽  
Vol 293 (43) ◽  
pp. 16596-16607 ◽  
Author(s):  
Jackson B. Trotman ◽  
Bernice A. Agana ◽  
Andrew J. Giltmier ◽  
Vicki H. Wysocki ◽  
Daniel R. Schoenberg

The N7-methylguanosine cap is added in the nucleus early in gene transcription and is a defining feature of eukaryotic mRNAs. Mammalian cells also possess cytoplasmic machinery for restoring the cap at uncapped or partially degraded RNA 5′ ends. Central to both pathways is capping enzyme (CE) (RNA guanylyltransferase and 5′-phosphatase (RNGTT)), a bifunctional, nuclear and cytoplasmic enzyme. CE is recruited to the cytoplasmic capping complex by binding of a C-terminal proline-rich sequence to the third Src homology 3 (SH3) domain of NCK adapter protein 1 (NCK1). To gain broader insight into the cellular context of cytoplasmic recapping, here we identified the protein interactome of cytoplasmic CE in human U2OS cells through two complementary approaches: chemical cross-linking and recovery with cytoplasmic CE and protein screening with proximity-dependent biotin identification (BioID). This strategy unexpectedly identified 66 proteins, 52 of which are RNA-binding proteins. We found that CE interacts with several of these proteins independently of RNA, mediated by sequences within its N-terminal triphosphatase domain, and we present a model describing how CE-binding proteins may function in defining recapping targets. This analysis also revealed that CE is a client protein of heat shock protein 90 (HSP90). Nuclear and cytoplasmic CEs were exquisitely sensitive to inhibition of HSP90, with both forms declining significantly following treatment with each of several HSP90 inhibitors. Importantly, steady-state levels of capped mRNAs decreased in cells treated with the HSP90 inhibitor geldanamycin, raising the possibility that the cytotoxic effect of these drugs may partially be due to a general reduction in translatable mRNAs.


2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Wenwen Chen ◽  
Wei Wang ◽  
Xiaoxia Sun ◽  
Shanshan Xie ◽  
Xiaoyang Xu ◽  
...  

Abstract Cell migration plays pivotal roles in many biological processes; however, its underlying mechanism remains unclear. Here, we find that NudC-like protein 2 (NudCL2), a cochaperone of heat shock protein 90 (Hsp90), modulates cell migration by stabilizing both myosin-9 and lissencephaly protein 1 (LIS1). Either knockdown or knockout of NudCL2 significantly increases single-cell migration, but has no significant effect on collective cell migration. Immunoprecipitation–mass spectrometry and western blotting analyses reveal that NudCL2 binds to myosin-9 in mammalian cells. Depletion of NudCL2 not only decreases myosin-9 protein levels, but also results in actin disorganization. Ectopic expression of myosin-9 efficiently reverses defects in actin disorganization and single-cell migration in cells depleted of NudCL2. Interestingly, knockdown of myosin-9 increases both single and collective cell migration. Depletion of LIS1, a NudCL2 client protein, suppresses both single and collective cell migration, which exhibits the opposite effect compared with myosin-9 depletion. Co-depletion of myosin-9 and LIS1 promotes single-cell migration, resembling the phenotype caused by NudCL2 depletion. Furthermore, inhibition of Hsp90 ATPase activity also reduces the Hsp90-interacting protein myosin-9 stability and increases single-cell migration. Forced expression of Hsp90 efficiently reverses myosin-9 protein instability and the defects induced by NudCL2 depletion, but not vice versa. Taken together, these data suggest that NudCL2 plays an important role in the precise regulation of cell migration by stabilizing both myosin-9 and LIS1 via Hsp90 pathway.


2018 ◽  
Vol 7 ◽  
pp. 54
Author(s):  
Riri Karnain ◽  
Yusrawati Yusrawati ◽  
Erkadius Erkadius

Ketuban pecah dini (KPD) berkaitan dengan peningkatan kadar Heat Shock Protein 90 (HSP 90) dan Tumor Necrosis Factor-α (TNF-α) yang muncul akibat stres oksidatif. Tujuan penelitian ini adalah membandingkan kadar HSP 90 dan TNF-α antara kehamilan preterm dengan KPD dan tanpa KPD. Penelitian ini menggunakan rancangan comparative study yang dilaksanakan di RSUD dr. Rasidin, RS Tk.III Reksodiwiryo, RS Bhayangkara, Puskesmas Lubuk Buaya dan Laboratorium Biomedik Fakultas Kedokteran Universitas Andalas dari bulan Oktober 2017 sampai Juli 2018. Jumlah sampel sebanyak 24 ibu hamil preterm dengan KPD dan 24 ibu hamil preterm tanpa KPD dengan menggunakan teknik consecutive sampling. Pemeriksaan HSP 90 dan TNF-α menggunakan metode ELISA. Uji normalitas data dengan uji Shapiro-Wilk. Analisis data komparatif menggunakan uji Mann-Whitney. Median kadar HSP 90 yaitu 11,21 ng/mL pada kehamilan preterm dengan KPD dan 9,15 ng/mL pada kehamilan preterm tanpa KPD dengan nilai p < 0,05. Median kadar TNF-α yaitu 0,21 ng/mL pada kehamilan preterm dengan KPD dan 0,17 ng/mL pada kehamilan preterm tanpa KPD dengan nilai p < 0,05. Kadar HSP 90 dan TNF-α pada kehamilan preterm dengan KPD lebih tinggi secara bermakna dibandingkan pada kehamilan preterm tanpa KPD.


2020 ◽  
Author(s):  
Zetao Ma ◽  
Deli Wang ◽  
Jian Weng ◽  
Sheng Zhang ◽  
Yuanshi Zhang

Abstract Background: Inflammation and apoptosis of chondrocytes are the pathological basis of osteoarthritis. Autophagy could alleviate the symptoms of inflammation and apoptosis. Previous study has shown that BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) can induce the occurrence and development of autophagy. However, it is unknown whether autophagy induced by BNIP3 can alleviate the inflammation and apoptosis of chondrocytes. Methods: We used the lentivirus to construct the overexpression BNIP3 chondrocytes. Next, the lipopolysaccharide (LPS) was used to stimulate these cells to simulate the physiological environment of osteoarthritis. After that, the enzyme-linked immunosorbent assays (ELISA) were performed to determine the levels of tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) and the flow cytometry was performed to detect the apoptosis rates of chondrocytes. At last, the expression of autophagy related proteins was detected with the western blotting. Results: The expression of BNIP3 was suppressed after treatment with LPS. However, overexpression of BNIP3 inhibited the secretion of proinflammatory factors (TNF-α, IL-1β and IL-6) and decreased the apoptosis of chondrocytes. Furthermore, overexpression of BNIP3 led to the upregulation of autophagy related proteins expression including little computer 3 (LC3), autophagy-related protein 7 (ATG7) and Beclin-1. Application of autophagy inhibitor recovered the expression of proinflammatory factors and apoptosis rates of chondrocytes. Conclusions: BNIP3 decreased the LPS induced inflammation and apoptosis of chondrocytes by activating the autophagy.


2003 ◽  
Vol 370 (3) ◽  
pp. 1011-1017 ◽  
Author(s):  
YunJin JUNG ◽  
Jennifer S. ISAACS ◽  
Sunmin LEE ◽  
Jane TREPEL ◽  
Zheng-gang LIU ◽  
...  

Tumour necrosis factor α (TNF-α) binds to its receptor (TNFR1) and activates both death- and inflammation/survival-related signalling pathways. The inflammation and survival-related signalling cascade results in the activation of the transcription factor, nuclear factor κB (NF-κB) and requires recruitment of receptor-interacting protein (RIP) to TNFR1. The indispensable role of RIP in TNF-induced NF-κB activation has been demonstrated in RIP-/- mice and in cell lines derived from such mice. In the present study, we show that the TNF-α-induced accumulation of hypoxia-inducible factor 1α (HIF-1α) protein in normoxic cells is RIP-dependent. Exposing fibroblasts derived from RIP-/- mice to either cobalt or PMA resulted in an equivalent HIF-1α induction to that seen in RIP+/+ fibroblasts. In contrast, RIP-/- cells were unable to induce HIF-1α in response to TNF-α. Further, transient transfection of NIH 3T3 cells with an NF-κB super-repressor plasmid (an inhibitor of NF-κB activation) also prevented HIF-1α induction by TNF-α. Surprisingly, although HIF-1α mRNA levels remained unchanged after induction by TNF, induction of HIF-1α protein by the cytokine was completely blocked by pretreatment with the transcription inhibitors actinomycin D and 5,6-dichlorobenzimidazole riboside. Finally, TNF failed to induce both HIF-1α, made resistant to von Hippel—Lindau (VHL), and wild-type HIF-1α transfected into VHL-/- cells. These results indicate that HIF-1α induction by TNF-α in normoxic cells is mediated by protein stabilization but is nonetheless uniquely dependent on NF-κB-driven transcription. Thus the results describe a novel mechanism of HIF-1α up-regulation and they identify HIF-1α as a unique component of the NF-κB-mediated inflammatory/survival response.


2004 ◽  
Vol 24 (24) ◽  
pp. 10757-10765 ◽  
Author(s):  
Marzenna Blonska ◽  
Yun You ◽  
Romas Geleziunas ◽  
Xin Lin

ABSTRACT Receptor-interacting protein (RIP) plays a critical role in tumor necrosis factor alpha (TNF-α)-induced NF-κB activation. However, the mechanism by which RIP mediates TNF-α-induced signal transduction is not fully understood. In this study, we reconstituted RIP-deficient Jurkat T cells with a fusion protein composed of full-length MEKK3 and the death domain of RIP (MEKK3-DD). In these cells, MEKK3-DD substitutes for RIP and directly associates with TRADD in TNF receptor complexes following TNF-α stimulation. We found that TNF-α-induced NF-κB activation was fully restored by MEKK3-DD in these cells. In contrast, expression of a fusion protein composed of NEMO, a component of the IκB kinase complex, and the death domain of RIP (NEMO-DD) cannot restore TNF-α-induced NF-κB activation in RIP-deficient cells. These results indicate that the role of RIP is to specifically recruit MEKK3 to the TNF-α receptor complex, whereas the forced recruitment of NEMO to the TNF-α receptor complex is insufficient for TNF-α-induced NF-κB activation. Although MEKK2 has a high degree of homology with MEKK3, MEKK2-DD, unlike MEKK3-DD, also fails to restore TNF-α-induced NF-κB activation in RIP-deficient cells, indicating that RIP-dependent recruitment of MEKK3 plays a specific role in TNF-α signaling.


2003 ◽  
Vol 23 (2) ◽  
pp. 665-676 ◽  
Author(s):  
Koh Ono ◽  
Sung O. Kim ◽  
Jiahuai Han

ABSTRACT Since a release of intracellular contents can induce local inflammatory responses, mechanisms that lead to loss of plasma membrane integrity in cell death are important to know. We showed previously that deficiency of the plasma membrane Ca2+ ATPase 4 (PMCA4) in L929 cells impaired tumor necrosis factor alpha (TNF-α)-induced enlargement of lysosomes and reduced cell death. The lysosomal changes can be determined by measuring the total volume of intracellular acidic compartments per cell (VAC), and we show here that inhibition of the increase in VAC due to PMCA4 deficiency not only reduced cell death but also converted TNF-α-induced cell death from a process involving disruption of the plasma membrane to a cell demise with a nearly intact plasma membrane. The importance of the size of lysosomes in determining plasma membrane integrity during cell death was supported by the observations that chemical inhibitors that reduce VAC also reduced the plasma membrane disruption induced by TNF-α in wild-type L929 cells, while increases in VAC due to genetic mutation, senescence, cell culture conditions, and chemical inhibitors all changed the morphology of cell death from one with an originally nearly intact plasma membrane to one with membrane disruption in a number of different cells. Moreover, the ATP depletion-mediated change from apoptosis to necrosis is also associated with the increases of VAC. The increase in lysosomal size may due to intracellular self-digestion of dying cells. Big lysosomes are easy to rupture, and the release of hydrolytic enzymes from ruptured lysosomes can cause plasma membrane disruption.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ziyu Yu ◽  
Nan Jiang ◽  
Wenru Su ◽  
Yehong Zhuo

Neuroinflammation is a complex inflammatory process in the nervous system that is expected to play a significant role in neurological diseases. Necroptosis is a kind of necrosis that triggers innate immune responses by rupturing dead cells and releasing intracellular components; it can be caused by Toll-like receptor (TLR)-3 and TLR-4 agonists, tumor necrosis factor (TNF), certain microbial infections, and T cell receptors. Necroptosis signaling is modulated by receptor-interacting protein kinase (RIPK) 1 when the activity of caspase-8 becomes compromised. Activated death receptors (DRs) cause the activation of RIPK1 and the RIPK1 kinase activity-dependent formation of an RIPK1-RIPK3-mixed lineage kinase domain-like protein (MLKL), which is complex II. RIPK3 phosphorylates MLKL, ultimately leading to necrosis through plasma membrane disruption and cell lysis. Current studies suggest that necroptosis is associated with the pathogenesis of neuroinflammatory diseases, such as Alzheimer’s disease, Parkinson’s disease, and traumatic brain injury. Inhibitors of necroptosis, such as necrostatin-1 (Nec-1) and stable variant of Nec (Nec-1s), have been proven to be effective in many neurological diseases. The purpose of this article is to illuminate the mechanism underlying necroptosis and the important role that necroptosis plays in neuroinflammatory diseases. Overall, this article shows a potential therapeutic strategy in which targeting necroptotic factors may improve the pathological changes and clinical symptoms of neuroinflammatory disorders.


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