Once inside the cell the LF is unbound from PA. The
target of LF is the second step in the cascade of MAPK. LF attacks MAPKK
in a still largely unknown manner. What is known is that LF attacks
almost the entire family of MAPKK; MKK4, MKK6 and MKK7, at the N-terminal.
However, LF does not attack MKK5. A reason for this could be the very
distant relationship this MAPKK has with teh rest of its family, as
can be seen in figure ? In addition to the MAPKK, LF also attacks MKK4,
MKK6 and MKK7. Because of its broad specificity, LF is thought to interact
with specific structural motifs to recognize its substrate and act at
full enzyme activity (Vitale et all, 2000).