Identification of a bacterial factor required for actin‐based motility of Burkholderia pseudomallei

• Published in: Molecular microbiology Vol. 56; no. 1; pp. 40 - 53
• Main Authors: Stevens, Mark P., Stevens, Joanne M., Jeng, Robert L., Taylor, Lowrie A., Wood, Michael W., Hawes, Pippa, Monaghan, Paul, Welch, Matthew D., Galyov, Edouard E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.04.2005; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Actins - metabolism; Amino Acid Sequence; Bacterial proteins; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Burkholderia pseudomallei - genetics; Burkholderia pseudomallei - metabolism; Burkholderia pseudomallei - physiology; Cell Line; Cellular biology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; HeLa Cells; Humans; Identification; Microbiology; Microfilament Proteins - chemistry; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; Miscellaneous; Molecular Sequence Data; Movement; Mutation; Pathogens; Proline; Bacteria; Burkholderia pseudomallei; Identification; Motility; Microbiology; Actin
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2004.04528.x

Summary Burkholderia pseudomallei is a Gram‐negative facultative intracellular pathogen that enters and escapes from eukaryotic cells using the power of actin polymerization. We have identified a bacterial protein (BimA) that is required for the ability of B. pseudomallei to induce the formation of actin tails. BimA contains proline‐rich motifs and WH2‐like domains and shares limited homology at the C‐terminus with the Yersinia autosecreted adhesin YadA. BimA is located at the pole of the bacterial cell at which actin polymerization occurs and mutation of bimA abolished actin‐based motility of the pathogen in J774.2 cells. Transient expression of BimA in HeLa cells resulted in F‐actin clustering reminiscent of that seen on WASP overexpression. Antibody‐mediated clustering of a CD32 chimera in which the cytoplasmic domain was replaced with BimA resulted in localization of the chimera to the tips of F‐actin enriched membrane protrusions. We report that purified truncated BimA protein binds monomeric actin in a concentration‐dependent manner in cosedimentation assays and that BimA stimulates actin polymerization in vitro in a manner independent of the cellular Arp2/3 complex.