Biochemical and localization analyses of putative type III secretion translocator proteins CopB and CopB2 of Chlamydia trachomatis reveal significant distinctions

B. Chellas-Géry, K. Wolf, J. Tisoncik, T. Hackstadt, K. A. Fields

Research output: Contribution to journalArticle

16 Scopus citations


Chlamydia spp. are among the many pathogenic Gram-negative bacteria that employ a type III secretion system (T3SS) to overcome host defenses and exploit available resources. Significant progress has been made in elucidating contributions of T3S to the pathogenesis of these medically important, obligate intracellular parasites, yet important questions remain. Chief among these is how secreted effector proteins traverse eukaryotic membranes to gain access to the host cytosol. Due to a complex developmental cycle, it is possible that chlamydiae utilize a different complement of proteins to accomplish translocation at different stages of development. We investigated this possibility by extending the characterization of C. trachomatis CopB and CopB2. CopB is detected early during infection but is depleted and not detected again until about 20 h postinfection. In contrast, CopB2 was detectible throughout development. CopB is associated with the inclusion membrane. Biochemical and ectopic expression analyses were consistent with peripheral association of CopB2 with inclusion membranes. This interaction correlated with development and required both chlamydial de novo protein synthesis and T3SS activity. Collectively, our data indicate that it is unlikely that CopB serves as the sole chlamydial translocation pore and that CopB2 is capable of association with the inclusion membrane.

Original languageEnglish (US)
Pages (from-to)3036-3045
Number of pages10
JournalInfection and Immunity
Issue number8
StatePublished - Aug 1 2011


ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

Cite this