FOCAL POINT  (Left to right) Jaeger Hamilton, Sarah Coulthurst, Matthias Trost, Frank Sargent, Tracy Palmer, Nicola Stanley-Wall, and colleagues (not pictured) identify a novel secretion pathway that the pathogenic bacterium S. marcescens uses to export chitinolytic proteins. Chitinase secretion depends on the expression of an inner membrane holin-like protein called ChiW and an endopeptidase called ChiX. ChiW appears to transport ChiX to the periplasm, where it may clear a path through the peptidoglycan layer to facilitate chitinase release. The image on the right uses fluorescent reporters to show that a subpopulation of S. marcescens cells coordinately express ChiX (red) and the chitinase ChiA (green).

GROUP PHOTO COURTESY OF SARAH HUSSAIN; HAMILTON PHOTO COURTESY OF THE AUTHORS