Poster abstracts

Poster number 33 submitted by Rodney Tollerson II

Translational control of swarming motility in Bacillus subtilis

Rodney Tollerson II (Department of Microbiology, Ohio State University, Columbus, Ohio, USA), Katherine R. Hummels (Department of Biology, Indiana University, Bloomington, Indiana, USA), Anne Witzky (Department of Molecular Genetics, Ohio State University, Columbus, Ohio, USA), Daniel B. Kearns (Department of Biology, Indiana University, Bloomington, Indiana, USA), Micheal Ibba (Department of Microbiology, Ohio State University, Columbus, Ohio, USA)

Abstract:
Control over the rate of translation in the cell is critical for viability. In bacteria, Elongation Factor P (EF-P) is one of a network of proteins that contribute to fine-tuning of translation elongation rate. Through binding between the P-site and E-site of the ribosome, EF-P helps to alleviate ribosomal pausing at specific motifs, most of which contain consecutive proline residues. By preventing ribosomes from stalling, EF-P effects a multitude of cellular processes, including translation elongation rate and transcription termination. EF-P requires post-translational modification at a conserved residue to perform its function effectively. Different organisms require different modifications, which can vary from molecules such as (R)-β-lysine in Salmonella enterica, to the recently discovered 5-aminopentanol moiety in Bacillus subtilis. Despite EF-P being conserved in bacteria, the enzymes required for post-translational modification are variable. Not only are the required modification enzymes variable between bacteria, the residues critical for EF-P function (with the exception of the site of modification) also have not been completely elucidated. Flagellar assembly genes in B. subtilis have a high content of diprolyl motifs. If there is a defect in EF-P function, B. subtilis is unable to undergo swarming motility because of ribosomal stalling at polyproline residues. By exploiting B. subtilis dependency on EF-P for swarming motility, critical residues for EF-P function can be determined. A green fluorescent protein (GFP) reporter system was used to determine if the mutations conferring swarming defects are caused by EF-P dependent ribosome stalling. Using the same GFP reporter system, the function of possible modification systems were explored. By determining the proteins and residues required for EF-P function, the mechanism and molecular basis of EF-P dependent translational control can be further elucidated.

References:
Navarre, W. W., Zou, S. B., Roy, H., Xie, J. L., Savchenko, A., Singer, A., … Fang, F. C. (2010). PoxA, YjeK, and elongation factor P coordinately modulate virulence and drug resistance in Salmonella enterica. Molecular Cell, 39(2), 209–221. http://doi.org/10.1016/j.molcel.2010.06.021

Rajkovic, A., Erickson, S., Witzky, A., Branson, O. E., Seo, J., Gafken, P. R., … Ibba, M. (2015). Cyclic Rhamnosylated Elongation Factor P Establishes Antibiotic Resistance in Pseudomonas aeruginosa. mBio, 6(3), 1–9. http://doi.org/10.1128/mBio.00823-15.Editor

Rajkovic, A., Hummels, K. R., Witzky, A., Erickson, S., Gafken, P. R., Whitelegge, J. P., … Ibba, M. (2016). Translation control of swarming proficiency in Bacillus subtilis by 5-amino-pentanolylated elongation factor P. Journal of Biological Chemistry, jbc.M115.712091. http://doi.org/10.1074/jbc.M115.712091

Keywords: EF-P, Swarming, Translation