type III secreted protein BipC: role in actin modulation and translocation activities required for the bacterial intracellular lifecycle.

Melioidosis, an infection caused by the facultative intracellular pathogen , has been classified as an emerging disease with the number of patients steadily increasing at an alarming rate. possess various virulence determinants that allow them to invade the host and evade the host immune response, such as the type III secretion systems (TTSS). The products of this specialized secretion system are particularly important for the infection. Lacking in one or more components of the TTSS demonstrated different degrees of defects in the intracellular lifecycle of . Further understanding the functional roles of proteins involved in TTSS will enable us to dissect the enigma of -host cell interaction. In this study, BipC (a translocator), which was previously reported to be involved in the pathogenesis of , was further characterized using the bioinformatics and molecular approaches. The gene, coding for a putative invasive protein, was first PCR amplified from K96243 genomic DNA and cloned into an expression vector for overexpression in . The soluble protein was subsequently purified and assayed for actin polymerization and depolymerization. BipC was verified to subvert the host actin dynamics as demonstrated by the capability to polymerize actin . Homology modeling was also attempted to predict the structure of BipC. Overall, our findings identified that the protein encoded by the gene plays a role as an effector involved in the actin binding activity to facilitate internalization of into the host cells.