ESX1 and infection: The Mtb ESX-1 protein secretion system has long been known to mediate phagosomal membrane damage (Manzanillo et al., 2012; Simeone et al., 2012); the mycobacterial lipid PDIM was more recently found to play a similar role in infection (Augenstreich et al., 2017; Barczak et al., 2017; Quigley et al., 2017).