Bacterial Toxin Co-ops Bcl-2

Science's STKE  25 Jul 2000:
Vol. 2000, Issue 42, pp. tw12
DOI: 10.1126/stke.2000.42.tw12

Tissue destruction that occurs upon infection with the bacterium Escherichia coli 0157:H17 is attributed in part to the bacterial factor verotoxin II (VTII), but the molecular mechanism of cell-death induction has not been clear. Suzuki et al. report that VTII has a pentameric sequence that is identical to a sequence found in the BH1 domain of mitochondrial Bcl-2, a protein that inhibits apoptosis. The BH1 domain of Bcl-2 mediates interaction with other Bcl-2 family members to suppress cell death. Biochemical analysis indicates that the pentameric sequence of VTII interacts with Bcl-2. When cells expressing Bcl-2 were treated with VTII, caspase 3 activation and subsequent apoptosis occurred. VTII also localized to mitochondria where Bcl-2 resides. The authors propose that VTII-Bcl-2 interaction is one of the death-induction mechanisms utilized by this bacterium. However, the molecular mechanism by which VTII induces cell death through Bcl-2 remains to be determined, but may involve blocking of Bcl-2.

Suzuki, A., Doi, H., Matsuzawa, F., Aikawa, S., Takiguchi, K., Kawano, H. Hayashida, M., and Ohno, S. (2000) Bcl-2 antiapoptotic protein mediates verotoxin II-induced cell death: Possible association between Bcl-2 and tissue failure by E. coli 0157:H7. Genes Dev. 14: 1734-1740. [Abstract] [Full Text]