Beschreibung:
Vibrio parahaemolyticus (V. para) is a Gram‐negative, halophilic bacteria that causes acute gastroenteritis in humans upon consumption of contaminated seafood. The V. para life cycle is facilitated by an array of virulence factors, including two type III secretion systems (T3SS). T3SS‐mediated translocation of effectors into host cells is dependent on delivery of each effector to the base of the T3SS needle by a chaperone. VopR is an effector secreted by the first V. para T3SS (T3SS1) that uses an N‐terminal PIP2 –binding domain (BPD) to localize to the plasma membrane and induces host cell rounding through an unknown catalytic mechanism. We hypothesize that VP1684, encoded by a gene directly upstream of vopR in the V. para genome, is the cognate chaperone of VopR, and that the BPD also constitutes the chaperone‐binding domain. Through affinity column purification coupled with FPLC filtration we demonstrate that VP1684 forms a homodimer in solution much like other T3SS effector chaperones, which corroborates bioinformatics analyses indicating that VP1684 shares conserved biochemical properties with T3SS effector chaperones. We also show that VP1684 forms a stable complex with VopR. Moreover, we reveal through confocal microscopy of HeLa cells infected with V. para that the VopR‐mediated cell rounding phenotype is VP1684‐dependent. Finally, we show via increases in host cell cAMP levels by translocated cyaA‐tagged effectors that the translocation of VopR into the host cell by T3SS1 also depends on the presence of VP1684. Taken together, these data suggest that VP1684 is acting as the previously unidentified cognate chaperone for VopR, and as a necessary factor in effector translocation plays a significant role in V. para pathogenicity.Support or Funding InformationThis work was funded by the HHMI, National Institutes of Health (NIH) grant R01‐AI056404, NIH grant 5T32AI007520‐20, the Welch Foundation grant I‐1561, and Once Upon a Time&[hellip]Foundation. STARS program funding provided by the state of Texas.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.