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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-9-12
pubmed:abstractText
Photorhabdus are Gram-negative, nematode-vectored bacteria that produce toxins to kill their insect hosts. The expression of one of these, Makes caterpillars floppy 1 (Mcf1), is sufficient to allow Escherichia coli to survive within, and kill, caterpillars which are otherwise able to clear E. coli infection. Mcf1 treated caterpillars show rapid loss of body turgor (the 'floppy' phenotype) and death is associated with massive apoptosis of both the midgut epithelium and insect phagocytes. Mammalian tissue culture cells treated with Mcf1 also display key features of apoptosis including zeiosis, apoptotic nuclear morphology, DNA laddering, activation of the effector caspase-3 and PARP cleavage. As Mcf1 carries a single BH3-like domain, here we investigate the hypothesis that this toxin promotes apoptosis via the mitochondrial pathway by mimicking a BH3 domain-only protein. Consistent with this hypothesis, a double mutant within the BH3-like domain causes a dramatic decline in apoptosis. Mcf1 also alters mitochondrial membrane potential and triggers the release of cytochrome c. Cells overexpressing Bcl-x(L), an anti-apoptotic Bcl-2 family member, are resistant to Mcf1-mediated apoptosis, as are cells deficient in Bax. In addition, translocation of Bax to the mitochondrion is observed in response to Mcf1 treatment. Together, these results show that Mcf1 mediates apoptosis via the mitochondrial pathway, and are consistent with the hypothesis that the BH3-like domain in Mcf1 is a functional requirement for the pro-apoptotic activity of Mcf1.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1462-5814
pubmed:author
pubmed:issnType
Print
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2470-84
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
The Mcf1 toxin induces apoptosis via the mitochondrial pathway and apoptosis is attenuated by mutation of the BH3-like domain.
pubmed:affiliation
Department of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9EZ, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't