CLPP and infection: ClpP, a highly conserved protease in prokaryotes and eukaryotes, is involved in the rapid adaption capacity during infection for Listeria monocytogenes, another facultative intracellular pathogen (Gaillot, Bregenholt, Jaubert, Di Santo, & Berche, 2001; Gaillot, Pellegrini, Bregenholt, Nair, & Berche, 2000).