Bid, Bax, and Lipids Cooperate to Form Supramolecular Openings in the Outer Mitochondrial Membrane

Kuwana, Tomomi; Mackey, Mason; Perkins, Guy; Ellisman, Mark H.; Latterich, Martin; Schneiter, Roger; Green, Douglas R.; Newmeyer, Donald D.

doi:10.1016/s0092-8674(02)01036-x

Cited by 1,333 publications

(1,232 citation statements)

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“…The interaction between TOM22 and Bax is transient, as revealed by kinetics in crosslinking experiments (Figure 2; Supplementary Figure S1), supporting the hypothesis that the association of Bax with TOM complex is a first step towards the formation of another structure, containing Bax-oligomer and possibly other mitochondrial targets. 12 The possible involvement of components of the mitochondrial import machinery in the targeting of Bcl-2 have been suggested by Nguyen et al 33 and it has been later reported that Bcl-2 interacts with TOM20, a TOM-complex protein. 34 results suggest that TOM components could play a major role in the control of the mitochondrial localization of the proteins of the Bcl-2 family.…”

Section: Discussionmentioning

confidence: 94%

“…Once inserted into the mitochondrial membrane, Bax induced the formation of the so-called mitochondrial membrane permeabilization (MMP) alone or in combination with other proteins and/or lipids. 12 Numerous study have shown that in a simple cell-free assay using isolated mitochondria and purified or in vitro translated (IVT) Bax could accurately reproduce early events of the Bax-induced permeabilization of the mitochondria. 10,[13][14][15] In order to elucidate the receptors involved in Bax association with mitochondria, we subjected isolated mitochondria to a mild proteolysis by trypsin using a protocol described earlier for the identification of components of the outer membrane import machinery.…”

Section: Resultsmentioning

confidence: 99%

“…28 Kuwana et al 12 have observed that Bax could induce a large permeabilization of liposomes in the absence of any proteins. Conversely, other results suggest that the presence of at least one mitochondrial protein was necessary for Bax to mediate outer MMP.…”

Section: Discussionmentioning

confidence: 99%

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TOM22, a core component of the mitochondria outer membrane protein translocation pore, is a mitochondrial receptor for the proapoptotic protein Bax

et al. 2006

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The association of Bax with mitochondria is an essential step in the implementation of apoptosis. By using a bacterial two-hybrid assay and crosslinking strategies, we have identified TOM22, a component of the translocase of the outer mitochondrial membrane (TOM), as a mitochondrial receptor of Bax. Peptide mapping showed that the interaction of Bax with TOM22 involved the first alpha helix of Bax and possibly two central alpha helices, which are homologous to the pore forming domains of some toxins. Antibodies directed against TOM22 or an antisense knockdown of the expression of TOM22 specifically inhibited the association of Bax with mitochondria and prevented Bax-dependent apoptosis. In yeast, a haploid strain for TOM22 exhibited a decreased expression of TOM22 and mitochondrial association of ectopically expressed human Bax. Our data provide a new perspective on the mechanism of association of Bax with mitochondria as it involves a classical import pathway. Apoptosis is a cell death program, which is central in many aspects to metazoan cell physiology and pathology. 1 Proteins of the Bcl-2 family are key players in the execution phase of apoptosis and their main functions is to control the release of apoptogenic proteins, such as cytochrome c (cyt c) and apoptosis inducing factor (AIF) from the mitochondria. 2 The Bcl-2 family is composed of antiapoptotic members such as Bcl-2 and proapoptotic proteins such as Bax or Bak, which share several domains of homology called BH. 1 In addition to these proteins, a third Bcl-2-related family of proteins have been identified as major amplifiers and/inducers of apoptosis. 2 The latter family has a homology to Bcl-2 limited to the BH3 domain and thus is called the BH3 only proteins. 2 The double knockout of Bax and Bak renders cells completely resistant to cell death 2 highlighting the essential role of these proteins during apoptosis.The determination of the solution structure of Bax showed its organization around nine a-helices (Ha1 to Ha9) 3 of which Ha2 contained most of the BH3 domain and Ha5 and Ha6, a putative pore forming domain that has been shown to be involved in the integration of Bax into the membrane. 4,5 Bax resides in an inactive state in the cytosol in many resting cells and is translocated to the mitochondria at the onset of apoptosis. 6 This translocation is associated with major conformational changes in Bax as both the amino-terminal end (N-T) and carboxy terminal end (C-T) become exposed facilitating its mitochondrial addressing and membrane insertion. 5,7 Bax mitochondrial membrane insertion and oligomerization is closely associated with the release into the cytosol of several intermembrane space proteins such as cyt c, second mitochondrial apoptotic factor (Smac) and AIF. 2 The nature of the different stimuli involved in the activation or in the inhibition of Bax is still largely unknown although this step remains one of the most critical points of control of the apoptotic program during which therapeutic interventions can be envisaged. 2 The mit...

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Section: Discussionmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

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TOM22, a core component of the mitochondria outer membrane protein translocation pore, is a mitochondrial receptor for the proapoptotic protein Bax

et al. 2006

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“…Such studies suggested that Bax alone (Saito et al, 2000) (or associated with VDAC) (Shimizu et al, 1999) would form a conduit selective for small proteins such as cyt c (14.5 kDa). Bax combined with another proapoptotic protein of the Bcl-2 family, t-Bid, can permeabilize cardiolipin-containing liposomes in vitro to fluorescent dextran of size up to 2000 kDa (Kuwana et al, 2002), correlating with the fact that apoptotic MOMP occurring in true cells is nonselective and affects all soluble intermembrane proteins, irrespective of their size (Patterson et al, 2000). The mechanisms of membrane permeabilization induced in isolated mitochondria exposed to recombinant Bax depends on its oligomerization status, although oligomerization by itself may be insufficient for the induction of MOMP (Poncet et al, 2004).…”

Section: Mitochondrial Membrane Permeabilization: the Central Event Omentioning

confidence: 99%

Mitochondria as therapeutic targets for cancer chemotherapy

et al. 2006

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Mitochondria are vital for cellular bioenergetics and play a central role in determining the point-of-no-return of the apoptotic process. As a consequence, mitochondria exert a dual function in carcinogenesis. Cancer-associated changes in cellular metabolism (the Warburg effect) influence mitochondrial function, and the invalidation of apoptosis is linked to an inhibition of mitochondrial outer membrane permeabilization (MOMP). On theoretical grounds, it is tempting to develop specific therapeutic interventions that target the mitochondrial Achilles' heel, rendering cancer cells metabolically unviable or subverting endogenous MOMP inhibitors. A variety of experimental therapeutic agents can directly target mitochondria, causing apoptosis induction. This applies to a heterogeneous collection of chemically unrelated compounds including positively charged a-helical peptides, agents designed to mimic the Bcl-2 homology domain 3 of Bcl-2-like proteins, ampholytic cations, metals and steroid-like compounds. Such MOMP inducers or facilitators can induce apoptosis by themselves (monotherapy) or facilitate apoptosis induction in combination therapies, bypassing chemoresistance against DNA-damaging agents. In addition, it is possible to design molecules that neutralize inhibitor of apoptosis proteins (IAPs) or heat shock protein 70 (HSP70). Such IAP or HSP70 inhibitors can mimic the action of mitochondrion-derived mediators (Smac/DIABLO, that is, second mitochondria-derived activator of caspases/direct inhibitor of apoptosis-binding protein with a low isoelectric point, in the case of IAPs; AIF, that is apoptosis-inducing factor, in the case of HSP70) and exert potent chemosensitizing effects.

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“…The microinjection needles had inner diameters of 5 mm with blunt tips. Recombinant Bcl-x LDC , 39 kindly donated by Dr. Newmeyer, was dissolved in microinjection buffer to a concentration of 1.5 mg/ml and was aspirated into the needle by negative suction. The protein suspension or buffer (B6 pl per oocyte) was injected into oocytes using a Piezo micromanipulator.…”

Section: Microinjection Of Oocytesmentioning

confidence: 99%

Molecular requirements for doxorubicin-mediated death in murine oocytes

Jurisicova

et al. 2006

Cell Death Differ

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We previously published evidence that oocytes exposed to doxorubicin (DXR), a widely used chemotherapeutic agent, rapidly undergo morphological and biochemical changes via discrete effector signaling pathways consistent with the occurrence of apoptosis. In this report, we elucidated the molecular requirements for actions of this drug in oocytes. Our results indicate that within 1 h of exposure DXR causes rapid DNA damage, and commits the oocyte to cytoplasmic fragmentation by the fourth hour, followed by delayed oocyte activation and execution of cytoplasmic fragmentation. Inhibitors that interfere with oocyte activation consistently rescue cytoplasmic fragmentation, but fail to suppress DNA damage. There was evidence of depletion of Bax, Caspase-2, MA-3 and Bcl-x transcripts, suggesting that modulations by DXR caused recruitment of these maternal transcripts into the translation process. Furthermore, sphingolipids such as sphingosine-1-phosphate and ceramide modulate DXR actions by, respectively, altering its intracellular trafficking, or by sustaining the drug's contact with DNA.

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Bid, Bax, and Lipids Cooperate to Form Supramolecular Openings in the Outer Mitochondrial Membrane

Cited by 1,333 publications

References 62 publications

TOM22, a core component of the mitochondria outer membrane protein translocation pore, is a mitochondrial receptor for the proapoptotic protein Bax

TOM22, a core component of the mitochondria outer membrane protein translocation pore, is a mitochondrial receptor for the proapoptotic protein Bax

Mitochondria as therapeutic targets for cancer chemotherapy

Molecular requirements for doxorubicin-mediated death in murine oocytes

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