scholarly journals Mitochondrial outer membrane permeabilization during apoptosis: The role of mitochondrial fission

2011 ◽  
Vol 1813 (4) ◽  
pp. 540-545 ◽  
Author(s):  
Thomas Landes ◽  
Jean-Claude Martinou
2018 ◽  
Author(s):  
Mateus Milani ◽  
Gerald M Cohen ◽  
Shankar Varadarajan

AbstractThe mitochondrial fission machinery, comprising a dynamin-related GTPase, DRP-1, is crucial for the regulation of mitochondrial membrane dynamics. Recent reports suggest that the tubular architecture of the endoplasmic reticulum (ER) marks the constriction sites on the mitochondria to facilitate DRP-1-mediated mitochondrial fission. However, the role of several ER shaping proteins that maintain the elaborate network of tubes and sheets in mitochondrial constriction and fission is not yet known. In this report, we demonstrate that modulation of the expression levels of key ER shaping proteins, namely Reticulon1 (RTN-1), Reticulon 4 (RTN-4), Lunapark-1 (LNP-1) and CLIMP-63, markedly decreased the extent of mitochondrial fission mediated by BH3 mimetics, despite no detectable changes in DRP-1 recruitment to the mitochondria. Furthermore, modulation of ER shaping proteins significantly decreased other hallmarks of apoptosis, such as mitochondrial outer membrane permeabilization, caspase activation and phosphatidylserine externalization, and functioned independently of mitochondrial cristae remodeling, thus demonstrating a requirement of ER shaping proteins and ER structural integrity for the efficient execution of the instrinsic apoptotic pathway.


PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e48571 ◽  
Author(s):  
António Rego ◽  
Margarida Costa ◽  
Susana Rodrigues Chaves ◽  
Nabil Matmati ◽  
Helena Pereira ◽  
...  

2007 ◽  
Vol 81 (14) ◽  
pp. 7504-7516 ◽  
Author(s):  
Arnaud Autret ◽  
Sandra Martin-Latil ◽  
Laurence Mousson ◽  
Aurélie Wirotius ◽  
Frédéric Petit ◽  
...  

ABSTRACT Poliovirus (PV) is the causal agent of paralytic poliomyelitis, a disease that involves the destruction of motor neurons associated with PV replication. In PV-infected mice, motor neurons die through an apoptotic process. However, mechanisms by which PV induces cell death in neuronal cells remain unclear. Here, we demonstrate that PV infection of neuronal IMR5 cells induces cytochrome c release from mitochondria and loss of mitochondrial transmembrane potential, both of which are evidence of mitochondrial outer membrane permeabilization. PV infection also activates Bax, a proapoptotic member of the Bcl-2 family; this activation involves its conformational change and its redistribution from the cytosol to mitochondria. Neutralization of Bax by vMIA protein expression prevents cytochrome c release, consistent with a contribution of PV-induced Bax activation to mitochondrial outer membrane permeabilization. Interestingly, we also found that c-Jun NH2-terminal kinase (JNK) is activated soon after PV infection and that the PV-cell receptor interaction alone is sufficient to induce JNK activation. Moreover, the pharmacological inhibition of JNK by SP600125 inhibits Bax activation and cytochrome c release. This is, to our knowledge, the first demonstration of JNK-mediated Bax-dependent apoptosis in PV-infected cells. Our findings contribute to our understanding of poliomyelitis pathogenesis at the cellular level.


2002 ◽  
Vol 159 (6) ◽  
pp. 923-929 ◽  
Author(s):  
Damien Arnoult ◽  
Philippe Parone ◽  
Jean-Claude Martinou ◽  
Bruno Antonsson ◽  
Jérôme Estaquier ◽  
...  

Mitochondrial outer membrane permeabilization by proapoptotic Bcl-2 family proteins, such as Bax, plays a crucial role in apoptosis induction. However, whether this only causes the intracytosolic release of inducers of caspase-dependent death, such as cytochrome c, or also of caspase-independent death, such as apoptosis-inducing factor (AIF) remains unknown. Here, we show that on isolated mitochondria, Bax causes the release of cytochrome c, but not of AIF, and the association of AIF with the mitochondrial inner membrane provides a simple explanation for its lack of release upon Bax-mediated outer membrane permeabilization. In cells overexpressing Bax or treated either with the Bax- or Bak-dependent proapoptotic drugs staurosporine or actinomycin D, or with hydrogen peroxide, caspase inhibitors did not affect the intracytosolic translocation of cytochrome c, but prevented that of AIF. These results provide a paradigm for mitochondria-dependent death pathways in which AIF cannot substitute for caspase executioners because its intracytosolic release occurs downstream of that of cytochrome c.


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