The University of Texas Medical School at Houston
Department of Microbiology and Molecular Genetics

Peter J. Christie, Ph.D.

  • Professor
  • Department of Microbiology &
    Molecular Genetics
  • University of Texas-Houston Medical School
    6431 Fannin Street, MSB 1.164
    Houston, Texas 77030
  • Telephone: (713) 500-5440
    Laboratory Telephone: (713) 500-7441


Ph.D., Cornell University, 1986

Postdoctoral Fellow, University of Washington & Stanford University

Research Interests:

Macromolecular transport processes during pathogenesis

Translocation of macromolecules between cells is a major area of biomedical interest. The focus of study in this laboratory is a type IV secretion (T4S) system of Agrobacterium tumefaciens. This system is ancestrally related and functionally similar to bacterial conjugation systems, as well as recently described protein translocation systems used by bacterial pathogens during the course of infection This T4S system mediates transfer of diverse substrates including oncogenic DNA and other DNA in the form of nucleoprotein particles, and of protein monomers across the A. tumefaciens cell envelope. These substrates are delivered to a variety of phylogenetically-diverse target bacterial or eukaryotic cells through a process dependent on direct cell-to-cell contact. This T4S system, assembled from VirD4 and 11 VirB subunits, is an especially attractive system for detailed mechanistic studies of macromolecular transport because of the ease of manipulation of A. tumefaciens, the large numbers of strains, constructs, and other molecular tools at hand, and the wealth of information about it and closely related transfer systems. We also are developing studies of other T4S systems of Gram-negative and Gram-positive bacterial pathogens.

The overall goal of work in this laboratory is to describe in detailed mechanistic terms the dynamic processes required for biogenesis and function of T4S systems during infection. We use powerful in vivo technologies developed in this laboratory and other state-of-the art biochemical and structure-based approaches to define how DNA and protein substrates are recruited to and translocated through the T4S channels.

    Questions of particular interest at this time include:
  1. How do three ATPase subunits energize machine assembly or function?
  2. How are substrates recruited to the secretion channel?
  3. What is the route of substrate transfer through the secretory apparatus?
  4. How do bacterial cells establish contact with bacterial or eukaryotic target cells to mediate intercellular substrate transfer?
  5. What are the cellular consequences of substrate trafficking in the host cell?

Supplemental Data

Selected Publications:

  • Christie P.J., Whitaker, N., Gonzalez-Rivera, C. (2013) Mechanism and structure of bacterial type IV secretion systems. Biochim. Biophys. Acta. In press.
  • Laverde-Gomez, J.A., Bhatty, M., Christie P.J. (2013) PrgK, a multidomain peptidoglycan hydrolase, is essential for conjugative transfer of the pheromone responsive plasmid pCF10. J. Bacteriol. In press.
  • Cascales, E., Atmakuri, K., Sarkar, M.K., Christie P.J. (2013) DNA substrate-induced activation of the Agrobacterium VirB/VirD4 type IV secretion system. J. Bacteriol. 195:2691-2704. [abstract]
  • Garza, I., Christie P.J. (2013) A putative transmembrane leucine zipper of Agrobacterium VirB10 is essential fro T-pilus biogenesis but not type IV secretion. J. Bacteriol. 195:3022-3034. [abstract]
  • Sarkar, M.M., Husnain, S.I., Jakubowski, S.J., Christie P.J. (2013) Isolation of bacterial type IV machine subassemblies. In Delcour, A. (ed.) Methods Mol. Biol. 966:187-204.
  • Bhatty, M., Laverde-Gomez, J.A., Christie P.J. (2013) The expanding bacterial type IV secretion lexicon. Res. Microbiol. 164:620-639. [abstract]
  • Li, F., Alvarez-Martinez, C., Chen, Y., Choi, K.-J., Yeo, H.-J., Christie P.J. (2012) Enterococcus faecalis PrgJ, a VirB4-like ATPase, mediates pCF10 conjugative transfer through substrate binding. J. Bacteriol. 194:4041-4051. [abstract]
  • Thanassi, D.G., Bliska, J.B., Christie P.J. (2012) Surface organelles assembled by secretion systems of Gram-negative bacteria: Diversity in structure and function. FEMS Microbiol. Rev. 36:1046-1085. [abstract]
  • Berry, T.M., Christie P.J. (2011) Caught in the act: The dialogue between bacteriophage R17 and the type IV secretion machine of plasmid R1. Mol. Microbiol. 82:1039-1043. [abstract]
  • Banta, L.M., Kerr, J.E., Cascales, E., Giuliano, M.E., Bailey, M.E., McKay, C., Chandran, V., Waksman, G.,Christie P.J. (2011) An Agrobacterium VirB10 mutation conferring a type IV secretion system gating defect. J. Bacteriol. 193:2566-2574. [abstract]
  • Kerr, J.E.,Christie P.J. (2010) Evidence for VirB4-mediated dislocation of membrane-integrated VirB2 pilin during biogenesis of the Agrobacterium VirB/VirD4 type IV secretion system. J. Bacteriol. 192:4923-4934. [abstract]
  • Christie P.J. (2009) Structural biology: Translocation chamber's secrets. Nature. 462:992-994. No abstract available.
  • Alvarez-Martinez, C.E.,Christie P.J. (2009) Biological diversity of prokaryotic type IV secretion systems. Microbiol. Mol. Biol. Rev. 73:775-808. [abstract]
  • Fronzes, R.,Christie P.J., Waksman, G. (2009) The structural biology of type IV secretion systems. Nat. Rev. Microbiol. 7:703-714. [abstract]
  • Jakubowski, S.J., Kerr, J.E., Garza, I., Krishnamoorthy, V., Bayliss, R., Waksman, G.,Christie P.J. (2009) Agrobacterium VirB10 domain requirements for type IV secretion and T pilus biogenesis. Mol. Microbiol. 71:779-794. [abstract]
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