Proceedings of the National Academy of Sciences of the United States of America

About the PNAS Member Editor
Name Isberg, Ralph R.
Location Tufts University
Primary Field Microbial Biology
 Election Citation
Isberg is a leader in the field of microbial pathogenesis. Two decades ago, Isberg identified the first protein shown to mediate uptake of a bacterial pathogen into a host cell, and since has developed numerous genetic and biochemical approaches to study invasion and intracellular replication of bacterial pathogens.
 Research Interests
My research has been devoted to understanding two processes that are critical for disease promoted by many bacterial pathogens: entry and growth within host cells. The main approach of my team has been to develop genetic and biochemical strateigies that allow analysis of the pathogen and its host cells. Investigation of an intestinal pathogen, Yersinia pseudotuberculosis, allowed identification of a single protein called invasin that is sufficient to allow entry into host cells. Detailed analyses of this protein by my laboratory resulted in the identification of the biochemical parameters critical for tricking target cell internalization of the pathogen. My laboratory also studies Legionella pneumophila, a bacterium that causes pneumonia by replicating within a membrane-bound compartment in macrophages, cells that normally kill invading microorganisms. Our laboratory has identified a bacterial machine that transfers proteins into host cells and is critical for formation of the replication compartment. The transferred proteins manipulate the movement of membranes and interfere with host cell death pathways. My most recent research efforts are directed toward developing strategies that solve functional redundancy in pathogens. This is a particularly vexing problem in which pathogens use multiple, apparently equally efficient, strategies to perform a single task.

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