Broad-Spectrum Regulation of Nonreceptor Tyrosine Kinases by the Bacterial ADP-Ribosyltransferase EspJ

Abstract

Tyrosine phosphorylation is key for signal transduction from exogenous stimuli, including the defense against pathogens. Conversely, pathogens can subvert protein phosphorylation to control host immune responses and facilitate invasion and dissemination. The bacterial effectors EspJ and SeoC are injected into host cells through a type III secretion system by enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively), Citrobacter rodentium, and Salmonella enterica, where they inhibit Src kinase by coupled amidation and ADP-ribosylation. C. rodentium, which is used to model EPEC and EHEC infections in humans, is a mouse pathogen triggering colonic crypt hyperplasia (CCH) and colitis. Enumeration of bacterial shedding and CCH confirmed that EspJ affects neither tolerance nor resistance to infection. However, comparison of the proteomes of intestinal epithelial cells isolated from mice infected with wild-type C. rodentium or C. rodentium encoding catalytically inactive EspJ revealed that EspJ-induced ADP-ribosylation regulates multiple nonreceptor tyrosine kinases in vivo. Investigation of the substrate repertoire of EspJ revealed that in HeLa and A549 cells, Src and Csk were significantly targeted; in polarized Caco2 cells, EspJ targeted Src and Csk and the Src family kinase (SFK) Yes1, while in differentiated Thp1 cells, EspJ modified Csk, the SFKs Hck and Lyn, the Tec family kinases Tec and Btk, and the adapter tyrosine kinase Syk. Furthermore, Abl (HeLa and Caco2) and Lyn (Caco2) were enriched specifically in the EspJ-containing samples. Biochemical assays revealed that EspJ, the only bacterial ADP-ribosyltransferase that targets mammalian kinases, controls immune responses and the Src/Csk signaling axis.

Faecal neutrophil elastase-antiprotease balance reflects colitis severity

“…We took advantage of the global proteomic analysis we had previously performed on IECs enriched from colons of infected C57 mice. 7,30 By comparing infected to uninfected IECs, an increased abundance of >1.5-fold change (log 2 >0.58) was observed for SerpinD1, SerpinA3M and SerpinA3N in four biological repeats. (Fig.…”

Vying for the control of inflammasomes: The cytosolic frontier of enteric bacterial pathogen–host interactions

“…Notably, EHEC Tir, which alone does not induce actin polymerisation, can only trigger pyroptotic signalling when provided with its cognate actin polymerising effector TccP (Garmendia et al, ; Goddard et al, ). Consistent with a role for Tir‐driven actin polymerisation in inflammasome activation, over‐expression of EspJ, an ADP ribosyl transferase (Young et al, ) targeting multiple non‐receptor tyrosine kinases (Pollard et al, ) that phosphorylate and activate EPEC Tir (Swimm et al, ), inhibits EPEC‐induced cell death (Goddard et al, ) (Figure a). Future studies are needed to investigate the interplay between the cytoskeleton and caspase‐4/11, which has been shown to modulate actin polymerisation at the leading edge (Li, Yin, & Yuan, ) and cell migration (Li et al, ).…”

Enteropathogenic Escherichia coli (EPEC) Recruitment of PAR Polarity Protein Atypical PKCζ to Pedestals and Cell–Cell Contacts Precedes Disruption of Tight Junctions in Intestinal Epithelial Cells

“…EPEC induces a pro-inflammatory response through several signaling pathways resulting in the activation of NF-κB, ERK1/2, p38, JNK and PKCζ, and the upregulation of IL-8 expression, which contribute to intestinal barrier dysfunction [42,[47][48][49]. EPEC also regulates the activity of multiple kinases, including the Src family, that contribute to actin polymerization [50,51]. Interestingly, Src family kinases contribute to Tir phosphorylation and actin pedestal formation [52,53].…”