Since BiP is considered as the key regulator and biomarker of the unfolded protein response (UPR), a highly conserved pathway in eukaryotes to restore cellular homeostasis following physiological stress exerted on the ER [17], and L. pneumophila has the ability to suppress certain arms of the UPR [18], our data provide a new insight to understand the strategies used by L. pneumophila to modulate the UPR during infection. Here, HSPA5 is linked to infection.