Identification of Potential Interaction Partners of a Brucella abortus VirB Effector Protein

MARCHESINI, M. I.; GUAIMAS F.; MORRONE SEIJO S.; COMERCI D. J

Chicago

Conferencia; 66th Annual Brucellosis Research Conference; 2013

Brucellosis Research Society

Brucella abortus, the causative agent of bovine brucellosis, invades and replicates within cells inside a membrane-bound compartment known as the Brucella containing vacuole (BCV). The type IV secretion system VirB is necessary for the translocation of effector proteins that modulate host cell signaling pathways to favor intracellular survival and replication. Identification of the targets and functions of these translocated effectors is essential to understand the role of VirB in pathogenesis. BPE123 is a B. abortus VirB-translocated effector recently identified by our group. In an attempt to identify host cell proteins interacting with BPE123, a pull-down assay was performed and human alpha-enolasa (ENO1) was identified by LC/MS-MS as a potential interaction partner of BPE123. These results were confirmed by Western Blot with a specific antibody against human ENO1. Microscopy studies revealed that ectopically expressed Myc-BPE123 accumulates in the endoplasmic reticulum in HeLa cells and displays a similar subcellular distribution to that of ENO1. Furthermore, during macrophage infection we observed recruitment of ENO1 to the vicinities of BPE123 positive VCBs, indicating that interaction with translocated BPE123 might also be occurring during the intracellular phase of B. abortus. Taken together, these results suggest a direct interaction between BPE123 and ENO1, a multifunctional protein that has been shown to be required for Brucella replication in host cells. Further experiments are underway to determine how BPE123-ENO1 interaction modulates the outcome of the infection process