Salmonellosis continues to be a major Public Health concern. The pathogenicity of Salmonella enterica requires the activity of two type III protein secretion systems (T3SS) encoded within its pathogenicity islands 1 and 2. These T3SSs direct the translocation into host cells of a battery of bacterial effector proteins, which working in conjunction with one another, modulate a variety of cellular processes including actin cytoskeleton dynamics, gene expression, vesicle trafficking, and programmed cell death. Modulation of these cellular activities allows Salmonella to gain access to and replicate within host cells, avoid host defense mechanisms, induce intestinal inflammation, and/or reach deeper tissues. Over the years, work in our laboratory supported by this Grant has focused on the study of the cell biology of the complex functional interface between Salmonella enterica serovar Typhimurium (S. Typhimurium) and its host cells shaped by the activities of T3SS effector proteins. During the last funding period we have made significant progress in the understanding of the structure and function of several Salmonella T3SS effector proteins, as well as on the cellular responses that they elicit. Despite this progress, the biochemical activities and/or cellular targets of the majority of these effector proteins remain uncharacterized. During the next funding period we plan to use a multidisciplinary approach to study S. Typhimurium effector proteins, identified their cellular targets and examine their contribution to the host/pathogen interactions.

Public Health Relevance

Salmonellosis continues to be a very significant global Public Health concern. In the US alone there are an estimated 1 million cases of Salmonella infection every year resulting in an annual economic burden of $2.8 billion. World-wide, Salmonella infections result in more than 200,000 annual deaths, mostly children in developing countries. There are no effective vaccines to protect against these infections. The studies proposed in this Grant application may serve as the foundation for novel therapeutic and prevention strategies against Salmonella infection.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Host Interactions with Bacterial Pathogens Study Section (HIBP)
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Alexander, William A
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Yale University
Schools of Medicine
New Haven
United States
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Kohler, Amanda C; Spanò, Stefania; Galán, Jorge E et al. (2014) Structural and enzymatic characterization of a host-specificity determinant from Salmonella. Acta Crystallogr D Biol Crystallogr 70:384-91
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Hannemann, Sebastian; Gao, Beile; Galan, Jorge E (2013) Salmonella modulation of host cell gene expression promotes its intracellular growth. PLoS Pathog 9:e1003668
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Du, Fangyong; Galan, Jorge E (2009) Selective inhibition of type III secretion activated signaling by the Salmonella effector AvrA. PLoS Pathog 5:e1000595

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