However, given the fact that many ER proteins were found to be PR-ubiquitinated after Legionella infection 44, 45 and our new data showing the cross-linking of multiple host substrates to the poly-Ub chains generated by Sdc and Sde, the association of ER-derived vesicles with the LCV can be explained by an alternative mechanism. Here, SDC1 is linked to legionellosis.