Biogenesis of a lipid-modified autotransporter in Bordetella

The Bordetellae are respiratory pathogens that can cause severe infections in both humans and animals, including whooping cough. In spite of widespread vaccination, whooping cough is undergoing resurgence worldwide, including a peak of 1,800 reported infections in British Columbia in 2000. Autotransporters are the largest class of secreted proteins produced by Bordetella and other Gram-negative bacteria. They possess a characteristic domain that facilitates their export from the cell, which is a factor implicated in microbial virulence (disease causing ability of infectious agents). Recently, a novel autotransporter (BapF) was identified from the genome sequences of Bordetella, and is predicted to be modified by lipids. Although lipid-modified autotransporters are rare, known ones contribute significantly to virulence in their respective organisms, and little is known about their mechanism of secretion. Peter Sims is investigating the role of BapF in the disease-causing properties of Bordetellae. His work will determine whether BapF is expressed (activated) in these bacteria, and how this autotransporter is secreted. Research into BapF may reveal new information regarding protein secretion in bacteria, and provide potential targets for fighting infection.