The Novel Protein Cj0371 Inhibits Chemotaxis of Campylobacter jejuni

Abstract

cj0371 is a novel gene that is associated with Campylobacter jejuni virulence, and an isogenic mutant of cj0371 showed hyper chemotaxis and motility. Chemotactic motility is an important virulence factor and is involved in C. jejuni pathogenesis. Campylobacter sp. has specific variations of the common chemotaxis components, including histidine autokinase CheA, coupling scaffold protein CheV, chemotaxis response regulator protein CheY and several chemoreceptor proteins. In this study, we used immunoprecipitation combined with LC-MS/MS analyses to screen six chemotaxis pathway proteins that potentially interact with the putative protein Cj0371. qRT-PCR was used to quantitatively analyze the expression of these chemotaxis genes and basic flagella genes. The results showed that the expression of cheV, cj1110c, and cj0262c was significantly up-regulated, and four flagella genes also had up-regulated expression in the cj0371 mutant. GST pull-down analyses found that Cj0371 interacted with the receiver domain of the CheV protein. Enzyme-coupled spectrophotometric assays showed that the ATPase activity of CheA was higher when Cj0371 was not present in the chemotaxis reaction medium. Therefore, we concludes that cj0371 has a negative influence on C. jejuni chemotaxis, which may occur by adjusting the receiver domain of CheV to influence chemotaxis. This paper provides a new component in the chemotaxis pathway of C. jejuni for the first time and highlight the complexity of this remarkable pathway.

The use of isothermal titration calorimetry to unravel chemotactic signalling mechanisms

“…Next to the six core proteins mentioned above, additional proteins were identified that are present in some but not all pathways, as exemplified by the CheD deamidase, the CheW‐REC domain fusion protein CheV or the CheC, CheZ and CheX phosphatases (Wuichet and Zhulin, 2010). Furthermore, the scientific community keeps identifying additional proteins that participate in some signalling cascades (Lertsethtakarn et al ., 2015; Xu et al ., 2016; Du et al ., 2018). The second level of complexity lies in the fact that bacteria frequently have multiple pathways that are composed of homologous signalling proteins.…”

So fragile yet so devious : Impact of L-fucose and D-glucose utilization on growth, metabolism and in vitro virulence of Campylobacter

“…. Furthermore, the upregulation of Cj0371 in isolate C. jejuni 286, but not in isolate C. jejuni NCTC11168, potentially influences the virulence of this isolate, as activation of this protein has a negative role on Campylobacters chemotaxis(Du et al, 2018).which is only produced in C. jejuni NCTC11168, is co-expressed with the fibronectin binding protein CadF (string-db.org), suggesting a possible link towards the increased fibronectin binding in this isolate. Four other virulence proteins were present in C. jejuni a number of putative virulence proteins were uniquely upregulated in the presence of L-fucose in C. jejuni 286, including exotoxin CdtC and the enterochelin uptake periplasmic binding protein CeuE.…”

“…Interestingly, Cj0371 is considered an "anti-virulence gene", as it plays a negative role on Campylobacters chemotaxis. In the study ofDu et al (2018), the authors hypothesized that functions encoded by such genes may support colonization and coexistence of Campylobacter in animal hosts, including chickens(Du et al, 2018). However, these findings do not directly provide a link with in vitro virulence data obtained with C. jejuni 286, as cells precultured in MEMα, MEMαF and MEMαA medium showed comparable low Caco-2 invasion and fibronectin binding capacity.…”