scholarly journals BopC Is a Novel Type III Effector Secreted byBordetella bronchisepticaand Has a Critical Role in Type III-dependent Necrotic Cell Death

2006 ◽  
Vol 281 (10) ◽  
pp. 6589-6600 ◽  
Author(s):  
Asaomi Kuwae ◽  
Takeshi Matsuzawa ◽  
Naoto Ishikawa ◽  
Hiroyuki Abe ◽  
Takashi Nonaka ◽  
...  
2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
José Belizário ◽  
Luiz Vieira-Cordeiro ◽  
Sylvia Enns

Under stress conditions, cells in living tissue die by apoptosis or necrosis depending on the activation of the key molecules within a dying cell that either transduce cell survival or death signals that actively destroy the sentenced cell. Multiple extracellular (pH, heat, oxidants, and detergents) or intracellular (DNA damage and Ca2+overload) stress conditions trigger various types of the nuclear, endoplasmic reticulum (ER), cytoplasmatic, and mitochondrion-centered signaling events that allow cells to preserve the DNA integrity, protein folding, energetic, ionic and redox homeostasis, thus escaping from injury. Along the transition from reversible to irreversible injury, death signaling is highly heterogeneous and damaged cells may engage autophagy, apoptotic, or necrotic cell death programs. Studies on multiple double- and triple- knockout mice identifiedcaspase-8,flip, andfaddgenes as key regulators of embryonic lethality and inflammation. Caspase-8 has a critical role in pro- and antinecrotic signaling pathways leading to the activation of receptor interacting protein kinase 1 (RIPK1), RIPK3, and the mixed kinase domain-like (MLKL) for a convergent execution pathway of necroptosis or regulated necrosis. Here we outline the recent discoveries into how the necrotic cell death execution pathway is engaged in many physiological and pathological outcome based on genetic analysis of knockout mice.


2021 ◽  
Author(s):  
Catalina Rodriguez-Puerto ◽  
Rupak Chakraborty ◽  
Raksha Singh ◽  
Perla Rocha-Loyola ◽  
Clemencia M. Rojas

The plant pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) has become a paradigm in plant-bacteria interactions due to its ability to cause disease in the model plant Arabidopsis thaliana. Pst DC3000 uses the type III secretion system to deliver type III secreted effectors (T3SEs) directly into the plant cytoplasm. Pst DC3000 T3SEs contribute to pathogenicity by suppressing plant defense responses and targeting plant’s physiological processes. Although the complete repertoire of effectors encoded in the Pst DC3000 genome have been identified, the specific function for most of them remains to be elucidated. The mitochondrial-localized T3E HopG1, suppresses plant defense responses and promotes the development of disease symptoms. Here, we show that HopG1 triggers necrotic cell death that enables the growth of non-adapted pathogens. We further showed that HopG1 interacts with the plant immunity-related protein AtNHR2B and that AtNHR2B attenuates HopG1- virulence functions.


2020 ◽  
Vol 117 (46) ◽  
pp. 29155-29165 ◽  
Author(s):  
Ping Li ◽  
Meiqin Hu ◽  
Ce Wang ◽  
Xinghua Feng ◽  
ZhuangZhuang Zhao ◽  
...  

LRRC8 family proteins on the plasma membrane play a critical role in cellular osmoregulation by forming volume-regulated anion channels (VRACs) necessary to prevent necrotic cell death. We demonstrate that intracellular LRRC8 proteins acting within lysosomes also play an essential role in cellular osmoregulation. LRRC8 proteins on lysosome membranes generate large lysosomal volume-regulated anion channel (Lyso-VRAC) currents in response to low cytoplasmic ionic strength conditions. When a double-leucine L706L707motif at the C terminus of LRRC8A was mutated to alanines, normal plasma membrane VRAC currents were still observed, but Lyso-VRAC currents were absent. We used this targeting mutant, as well as pharmacological tools, to demonstrate that Lyso-VRAC currents are necessary for the formation of large lysosome-derived vacuoles, which store and then expel excess water to maintain cytosolic water homeostasis. Thus, Lyso-VRACs allow lysosomes of mammalian cells to act as the cell`s “bladder.” When Lyso-VRAC current was selectively eliminated, the extent of necrotic cell death to sustained stress was greatly increased, not only in response to hypoosmotic stress, but also to hypoxic and hypothermic stresses. Thus Lyso-VRACs play an essential role in enabling cells to mount successful homeostatic responses to multiple stressors.


Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
CM Strüh ◽  
S Jäger ◽  
CM Schempp ◽  
T Jakob ◽  
A Scheffler ◽  
...  

2007 ◽  
Vol 26 (6) ◽  
pp. 769-771 ◽  
Author(s):  
Tom Vanden Berghe ◽  
Wim Declercq ◽  
Peter Vandenabeele

APOPTOSIS ◽  
2010 ◽  
Vol 16 (2) ◽  
pp. 114-126 ◽  
Author(s):  
Jee-Youn Kim ◽  
Yong-Jun Kim ◽  
Sun Lee ◽  
Jae-Hoon Park

2005 ◽  
Vol 168 (4) ◽  
pp. 545-551 ◽  
Author(s):  
Xavier Saelens ◽  
Nele Festjens ◽  
Eef Parthoens ◽  
Isabel Vanoverberghe ◽  
Michael Kalai ◽  
...  

Cell death is an intrinsic part of metazoan development and mammalian immune regulation. Whereas the molecular events orchestrating apoptosis have been characterized extensively, little is known about the biochemistry of necrotic cell death. Here, we show that, in contrast to apoptosis, the induction of necrosis does not lead to the shut down of protein synthesis. The rapid drop in protein synthesis observed in apoptosis correlates with caspase-dependent breakdown of eukaryotic translation initiation factor (eIF) 4G, activation of the double-stranded RNA-activated protein kinase PKR, and phosphorylation of its substrate eIF2-α. In necrosis induced by tumor necrosis factor, double-stranded RNA, or viral infection, de novo protein synthesis persists and 28S ribosomal RNA fragmentation, eIF2-α phosphorylation, and proteolytic activation of PKR are absent. Collectively, these results show that, in contrast to apoptotic cells, necrotic dying cells retain the opportunity to synthesize proteins.


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