1988, Ph.D. in biochemistry and molecular biology - University of Texas Health Science Center at Houston
1998 – 2004, Postdoc, CIID - IBT - Texas A&M Health Science Center; Houston, TX
Bacteria and host interactions; immune evasion; microbes and cancer.
This lab is interested in the broad area of bacterial-host interactions. The manifestation and progression of infectious diseases are determined by the combined effects of actions of bacterial factors and host reactions to the bacteria. Furthermore, some of the bacterial – host interactions may cause alterations in host physiological or cellular processes that can contribute to other types of diseases including immune disorders and cancer. Currently there are two lines of research in the lab.
1. Bacterial manipulation of the complement system. The complement system is not only the first line of defense against microorganisms, but also links the innate immune system to the adaptive immune system. It is not surprising that manipulation of the complement system is a strategy commonly adopted by bacterial pathogens. Research in lab demonstrated that spores of Bacillus anthracis, a Gram-positive bacterium that causes anthrax, actively recruit components of the complement system. The goals are to understand the molecular mechanism of the interactions and the precise biological functions of the interactions. The lab is also interested in other bacterial pathogens that may possess a similar strategy of complement manipulation as that of B. anthracis.
2. Microbes in colon cancer. The goal is to understand the relationship between certain bacterial pathogens and colon cancer. In vitro culture systems and animal models are utilized in the research.
Yi Xu, Douglas R. Keene, Janusz M. Bujnicki, Magnus Höök, and Slawomir Lukomski. 2002. ‘Streptococcal Scl1 and Scl2 proteins form collagen-like triple helices’. J. Biol. Chem. 277: 27312-27318.
Ponnuraj, K., Xu, Y., Moore, D., Deivanayagam, C. C., Boque, L., Höök, M., Narayana, S. V., 2002, ‘Crystallization and preliminary X-ray crystallographic analysis of Ace: a collagen-binding MSCRAMM from Enterococcus faecalis’, Biochim. Biophys. Acta. 1596: 173-6
Pikas, D. S., Brown, E. L, Gurusiddappa, S., Lee, L. Y., Xu, Y., Höök, M., 2003. ‘Decorin-binding sites in the adhesin DbpA from Borrelia burgdorferi: a synthetic peptide approach’, J. Biol. Chem., 278: 30920-6
Yi Xu, Jorge M. Rivas, Eric L. Brown, Xiaowen Liang, and Magnus Höök. 2004. ‘The virulence potential of the staphylococcal adhesin CNA in experimental arthritis is determined by its affinity for collagen’, J. Infect. Dis., 189:2323-2333.
Karthe Ponnuraj, M. Gabriela Bowden, Stacey Davis, S. Gurusiddappa, Dwight Moore, Damon Choe, Yi Xu, Magnus Höök, and Sthanam V. L. Narayana. 2003. ‘A “dock, lock, and latch” structural model for a Staphylococcal adhesin binding to fibrinogen’. Cell 115(2): 217-28.
Jouko Sillanpää, Yi Xu, Sreedhar R. Nallapareddy, Barbara E. Murray and Magnus Höök. ‘A family of putative MSCRAMMs from Enterococcus faecalis’. Microbiology, 2004, 150(Pt 7):2069-78.
Yi Xu, Xiaowen Liang, Yahua Chen, Theresa M. Koehler, and Magnus Höök. ‘Identification and biochemical characterization of two novel collagen binding MSCRAMMs of Bacillus anthracis’. J. Biol. Chem. 2004, 179 (50):51760-8.
Humtsoe JO, Kim JK, Xu Y, Keene DR, Höök M, Lukomski S, Wary KK. ‘A streptococcal collagen-like protein interacts with the alpha 2beta 1 integrin and induces intracellular signaling’. J. Biol. Chem. 2005, 280(14):13848-57.
Bowden MG, Chen W, Singvall J, Xu Y, Peacock SJ, Valtulina V, Speziale P, Höök M. ‘Identification and preliminary characterization of cell-wall-anchored proteins of Staphylococcus epidermidis’ Microbiology. 2005 May;151(Pt 5):1453-64.
Kim JK, Xu Y, Keene DR, Gurusiddappa S, Liang X, Wary KK, Höök M. ‘A novel binding site in collagen type III for the integrins, alpha 1beta 1 and alpha 2beta 1’ J Biol Chem. 2005, 280(37):32512-20
Yinong Zong, Yi Xu, Xiaowen Liang, Douglas R. Keene, Agneta Höök, S. Gurusiddappa, Magnus Höök, and Sthanam VL Narayana. ‘A “collagen hug” model for Staphylococcus aureus CNA binding to collagen’. EMBO J. 2005 Dec 21;24(24):4224-36.
Runlin Han, Antoni Zwiefka, Clayton C. Caswell, Yi Xu, Douglas R. Keene, Ewa Lukomska, Zhihong Zhao, Magus Hook, and Slawomir Lukomski. ‘Assessment of prokaryotic collagen-like sequences derived from streptococcal Scl1 and Scl2 proteins as a source of recombinant GXY polymers’. Appl. Microbiol. Biotechnol., 2006 March, 72(1):109-15.
Brooke H. Russell, Ranga Vasan, Douglas R. Keene, and Yi Xu. ‘Bacillus anthracis internalization by human fibroblasts and epithelial cells’. Cellular Microbiology. 2007, 9(5): 1262-1274
Brooke H. Russell, Ranga Vasan, Douglas R. Keene, Theresa M. Koehler, and Yi Xu. ‘Potential dissemination of Bacillus anthracis utilizing human lung epithelial cells’. Cellular Microbiology. Published online Dec 17, 2007.