Michael G. Caparon, Jr, PhD

Molecular Microbiology

Molecular Microbiology and Microbial Pathogenesis Program
Plant and Microbial Biosciences Program
Biochemistry, Biophysics, and Structural Biology Program
Molecular Genetics and Genomics Program

  • 314-362-1485

  • 314-362-7650

  • 314-362-1232

  • 10250 McDonnell Pediatric Research Building

  • caparon@wustl.edu

  • http://microbiology.wustl.edu/Bio_Sketches/caparonCV.html

  • bacteriology, gene expression, inflammation, microbial pathogenesis, toxin

  • Genetics and virulence of the pathogenetic streptococci

Research Abstract:

Research in my laboratory is directed at understanding the interaction of pathogenic Gram positive bacteria and their human hosts. Of particular interest is Streptococcus pyogenes, the causative agent of diseases including, strep throat, scarlet fever and rheumatic fever.

Signaling interactions between the microbe and host cells are a focus, including how the host environment influences regulation of genes, and how the streptococcus secretes proteins that influence the behavior of host cells. As a model of environmental regulation, state-of-the-art genetic and transcription profiling approaches in combination with animal models of infection, including a novel streptococcus-zebrafish model of host-pathogen interaction are used to examine how the streptococci respond to oxidative stress and the role this response contributes to the interaction with host cells in inflamed tissues.

Signaling interactions are influenced by the large number of protein toxins secreted by the streptococcus. However, mechanisms of protein secretion and folding are not well understood in Gram positive bacteria. Through analysis of a secreted protease, we have discovered several components of a unique gene expression, secretion and processing pathway required for biogenesis of an active extracellular protease.

Finally, in analyzing how streptococci manipulate the signaling responses of host cells, we have identified "Cytolysin-Mediated Translocation," a novel pathway for the injection of streptococcal proteins directly into the cytosol of host cells. At least one of the translocated proteins has characteristics of a eukaryotic signal transduction factor. This pathway may be widespread among Gram positive pathogens and be the functional equivalent of a Type III secretion pathway.

Selected Publications:

Rosch J, Caparon M. A microdomaim for protein secretion in Gram-positive organisms. Science 2004. Forthcoming.

Brenot A, King KY, Janowiak B, Griffith O, Caparon MG. Contribution of glutathione peroxidase to the virulence of Streptococcus pyogenes. Infect Immun 2004 72:408-413.

Lyon WR, Caparon MG. Related Articles, Links Abstract Role for serine protease HtrA (DegP) of Streptococcus pyogenes in the biogenesis of virulence factors SpeB and the hemolysin streptolysin S. Infect Immun 2004 72:1618-2165.

Neely MN, Pfeifer JD, Caparon M. Streptococcus-zebrafish model of bacterial pathogenesis. Infect Immun 2002 70:3904-3914.

Madden JC, Ruiz N, Caparon M. Cytolysin-mediated translocation (CMT): A functional equivalent of type III secretion in gram-positive bacteria. Cell 2001 104:143-152.

Last Updated: 8/3/2011 2:07:21 PM

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