PIP2 (green) is eliminated by bacteria (pink) that express SigD (right).
Grinstein/Macmillan
The groups studied different pathogens, but both came to similar conclusions. Both bacteria, Shigella and Salmonella, inject several invasion-promoting proteins into the host, including a protein with similarity to a mammalian inositol phosphatase. Mauricio Terebiznik, Sergio Grinstein (Hospital for Sick Children, Toronto, ON), and colleagues watched how phosphoinositides were affected during Salmonella infection. They found that one PIP2 species, PtdIns(4,5)P2, was depleted from the base of membrane ruffles that formed where bacteria were pushing to get in, thanks to the phosphatase activity of the SigD effector protein. Like SigD, the Shigella effector IpgD studied by Kirsten Nieburh (Institut Pasteur, Paris, France), Bernard Payrastre (INSERM, Toulouse, France),...
