Biochemistry and Molecular Biology
Penn State Science
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Kathleen Postle

Kathleen Postle

Main Content

  • Professor of Biochemistry and Molecular Biology
301 Althouse Laboratory
University Park, PA 16802
Phone: (814) 863-7568

Research Interests

Signal transduction and iron transport in bacteria as a target for novel antibiotic development

Graduate Programs


Research Summary

Signal Transduction and Iron Transport in Bacteria

Gram negative bacteria are surrounded by a double concentric membrane system--the cytoplasmic, or inner, membrane and the outer membrane. Dr. Postle’s lab is studying a form of signal transduction in Escherichia coli: the means by which cytoplasmic membrane energy (protonmotive force) is transduced to transport proteins in the outer membrane by TonB protein. Current information indicates that energy is transduced by a series of conformational changes in cytoplasmic membrane TonB protein which are transmitted to the outer membrane transport proteins by direct physical contact. An understanding of the molecular mechanism of TonB-dependent energy transduction will provide unique insights into all signal transduction processes. Furthermore, the ability of many bacterial pathogens to obtain iron from host proteins like transferrin is a TonB-dependent process. Since pathogens lacking TonB can be compromised in their ability to cause disease, our understanding of the mechanism of TonB-dependent energy transduction can lead to the development of novel chemotherapeutics.

Selected Publications

  • Gresock M. G. and K. Postle. 2017.  Going outside the TonB box: identification of novel FepA-TonB interactions in vivo. J Bacteriol. 199: e00649-16. PMCID:PMC5405211
  • Gresock, M.G., Kastead, K.A., and K. Postle.  2015.  From homodimer to heterodimer and back: elucidating the TonB energy transduction cycle.  J. Bacteriol.  197:3433-3445.  This article wasSpotlighted” by J. Bacteriol. as an “Article of Significant Interest Selected from This Issue by the Editors” PMCID:PMC4621073
  • Bulathsinghala, C.M., Jana, B., Baker, K.R. and K. Postle.  2013.  ExbB cytoplasmic loop deletions cause immediate, proton motive force-independent growth arrest.  J. Bacteriol.  195:4580-4591. PMCID:PMC3807443
  • Baker, K.R., and K. Postle.  2013.  Mutations in the Escherichia coli ExbB transmembrane domains identify scaffolding and signal transduction functions and exclude participation in a proton pathway.  J. Bacteriol. 195:2898-2911. PMCID:PMC3697263
  • Ollis, A. A., Kumar, A., and K. Postle.  2012. The ExbD periplasmic domain contains distinct functional regions for two stages in TonB energization.  J. Bacteriol. 194:3069-77. PMCID:PMC3370882
  • Ollis, A. A., and K. Postle. 2012. Identification of functionally important TonB-ExbD periplasmic domain interactions in vivo. J. Bacteriol. 194:3078-87.  PMCID:PMC3370880
  • Ollis, A. A., and K. Postle. 2012. ExbD mutants define initial stages in TonB energization. J Mol Biol 415:237-47. PMCID:PMC3258360
  • Ollis, A. A., and K. Postle. 2011. The same periplasmic ExbD residues mediate in vivo interactions between ExbD homodimers and ExbD-TonB heterodimers. J Bacteriol 193:6852-63. PMCID:PMC3232860
  • Gresock, M. G., M. I. Savenkova, R. A. Larsen, A. A. Ollis, and K. Postle. 2011. Death of the TonB shuttle hypothesis. Front Microbiol 2:206. PMCID:PMC3191458
  • Jana, B., M. Manning, and K. Postle. 2011. Mutations in the ExbB cytoplasmic carboxy terminus prevent energy-dependent interaction between the TonB and ExbD periplasmic domains. J Bacteriol 193:5649-57. PMCID:PMC3187225
  • Swayne, C., and K. Postle. 2011. Taking the Escherichia coli TonB Transmembrane Domain "Offline"? Non-protonatable Asn Substitutes Fully for TonB His20. J Bacteriol 193:3693-3701. PMCID:PMC3147502
  • Postle, K., Kastead, K.A., Gresock, M.G., and C.D. Swayne. 2010. The TonB dimeric crystal structures do not exist in vivo. MBio. 1:e00307-10. PMCID: PMC3005593