A secreted effector with a dual role as a toxin and as a transcriptional factor

Abstract

Bacteria have evolved multiple secretion systems for delivering effector proteins into the cytosol of neighboring cells, but the roles of many of these effectors remain unknown. Here, we show that Yersinia pseudotuberculosis secretes an effector, CccR, that can act both as a toxin and as a transcriptional factor. The effector is secreted by a type VI secretion system (T6SS) and can enter nearby cells of the same species and other species (such as Escherichia coli) via cell-cell contact and in a contact-independent manner. CccR contains an N-terminal FIC domain and a C-terminal DNA-binding domain. In Y. pseudotuberculosis cells, CccR inhibits its own expression by binding through its DNA-binding domain to the cccR promoter, and affects the expression of other genes through unclear mechanisms. In E. coli cells, the FIC domain of CccR AMPylates the cell division protein FtsZ, inducing cell filamentation and growth arrest. Thus, our results indicate that CccR has a dual role, modulating gene expression in neighboring cells of the same species, and inhibiting the growth of competitors.

Metagenome diversity illuminates origins of pathogen effectors

“…Some intracellular bacteria harbor FIC domain-containing proteins 155 and several human pathogens secrete effectors with FIC domains into host cells to subvert cellular processes 163 . Furthermore, a recent report illustrated that Yersinia pseudotuberculosis utilizes a FIC domain effector, CccR, that alters conspecific gene expression and inhibits congener growth 164 . Many Rickettsia genomes encode multiple divergent FIC proteins ( TABLE S2 ); however, to our knowledge, none of these proteins are known to be secreted by rickettsiae.…”

Streptothricin-F Inhibition of FtsZ Function: A Promising Approach for Controlling Pseudomonas syringae pv. actinidiae

“…GTPase activity assay kit was used to test the GTPase activity of FtsZ . The purified FtsZ obtained in Tris–HCl buffer was thawed on ice, and the GTPase activity assay kit (MAK113, Sigma) was employed in a 96-well plate at room temperature.…”

“…GTPase activity assay kit was used to test the GTPase activity of FtsZ. 31 The purified FtsZ obtained in Tris−HCl buffer was thawed on ice, and the GTPase activity assay kit (MAK113, Sigma) was employed in a 96-well plate at room temperature. FtsZ was preincubated with a specific quantity of ST-F in 20 μL of assay buffer (40 mM Tris, 8.0 mM NaCl, 8 mM MgAc 2 , and 1 mM EDTA, pH 7.5), and the final volume was adjusted to 30 mL with ddH 2 O.…”

“…Purification of Cell Division Proteins. According to the experimental procedures described, 31 the FtsZ gene fragment was amplified using the Phanta Max high-fidelity DNA polymerase (P505) with M228 genomic DNA as the template. Subsequently, the amplified gene fragment was integrated into linearized pET30a plasmid using the ClonExpress MultiS One Step Cloning Kit (C112), resulting in the generation of recombinant plasmids.…”

“…To investigate the effect of ST-F on the polymerization ability of FtsZ, transmission electron microscopy (TEM) was employed for observation. 31 Purified FtsZ protein (12.5 mM) was incubated with ST-F (2 μM) in an assembly buffer (50 mM HEPES-KOH, pH 7.5, 300 mM KAc, 5 mM MgAc 2 , 1 mM GTP) at a temperature of 30 °C for a duration of 30 min. Following the addition of 1 mM GTP to initiate FtsZ polymerization, the reaction mixture was further incubated for 30 min.…”