Pathogenic bacteria can inject into host cells virulence factors via the so-called type III machinery. Li et al. describe a family of bacterial virulence factors that have a previously unknown phosphothreonine lyase activity that can remove the phosphate from signaling mitogen-activated protein kinase family members involved in innate immunity. This family of effectors is important in the virulence of a variety of animal and plant bacterial pathogens, including Shigella, Salmonella, and Pseudomonas syringae.
H. Li, H. Xu, Y. Zhou, J. Zhang, C. Long, S. Li, S. Chen. J.-M. Zhou, F. Shao, The phosphothreonine lyase activity of a bacterial type III effector family. Science 315, 1000-1003 (2007). [Abstract] [Full Text]