How cells defend their cytosol against bacteria: LPS ubiquitylation and other tricks
Intracellular pathogens colonize specific subcellular niches, reflecting the pathogen's need for host factors and nutrients as well as its ability to neutralise compartment-specific host defence mechanisms. Most intracellular bacteria dwell in phagosomes and only few have succeeded in conquering the cytosol, a perhaps counterintuitive situation given the abundance of nutrients in the cytosol. Potent cytosolic defense mechanisms must therefore exist. I will discuss how cells defend their cytosol against bacterial invasion through autophagy as we have discovered novel triggers for anti-bacterial autophagy, namely the detection of sphingomyelin on damaged phagosomes by TECPR1 and the ubiquitylation of LPS on Gram-negative bacteria by RNF213.