The signaling pathway involves a new form of protein modification called AMPylation in order to relay instructions to change cell behavior and has been found to be used by almost all organisms, Luo said.
The bacterial enzyme discovered by the Purdue team, named SidD, reverses or stops the AMPylation process, he said.
"It had not been known before if the AMPylation signaling process was reversible or if it was regulated by specific enzymes," Luo said. "Now we know that it is, and we have a more complete picture that will allow us to use it as a scientific tool to learn more about complex cellular processes. By being able to turn the signaling on and off, we can control different activities and detect mechanisms we wouldn't see under normal physiological conditions."
The bacterium affects the host cell's functions differently during different phases of the infection process, tapping into signaling pathways to turn on and off certain natural cellular activities. SidD stops the AMPylation process four hours after the start of infection in order to reverse an earlier modification that would be detrimental to the cell if left in place, he said.
"During its process of infection, the bacteria can trigger reactions that can lead to the death of the host cell," Luo said. "Of course this is not in the best interest of the bacteria because it would no longer be able to replicate and continue infection, so it has evolved mechanisms to neutralize such reactions and keep the host cell alive."
Luo said further investigation of the structure and function of the SidD enzyme is needed to better understand its role in the infection process and its involvement in other cellular processes.
"The more we can learn about an infectious agent, the better equipped we will be to design a therapy to fight it,"
|Contact: Elizabeth K. Gardner|