Fig. 5. Proposed model of BFT mechanism of action. BFT binds to and probably cleaves a specific host cell receptor (Wu et al., 2006), potentially activating a host cell protease that either alone or complexed with BFT then cleaves the E-cadherin ectodomain and stimulates activation of -secretase that cleaves the cell-associated E-cadherin remnant. Alternatively, BFT receptor binding may stimulate signal transduction activating a host cell protease that stimulates cleavage of E-cadherin.