This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. It has been clearly established that proper function and regulation of many eukaryotic proteins and protein complexes require specific subcellular localization. Recent studies have demonstrated that many bacterial proteins are also sequestered to distinct cellular locations. Specifically, a number of chemotaxis, partitioning, cell division, and regulatory proteins in Escherichia coli, Caulobacter crescentus, and Bacillus subtilis, have been shown to be preferentially localized to the cell poles (for review see Lybarger and Maddock, 2001). These studies suggest that the ends of the bacterial cell provide a unique microenvironment, distinct from the rest of the cell, and demonstrate that organization of the bacterial cell is highly complex. One of our long-term goals is to assign a biological role to the clustering of chemoreceptors in bacteria and to assign clustering a biological role. By describing the function of chemoreceptor clustering in a well-characterized and genetically amenable model system like E. coli, we can quickly and conclusively answer some very specific but widely applicable questions. Moreover, relative to the majority of motile bacteria that contain large numbers of chemotaxis genes, E. coli represents a stream-lined cell with a simple chemotaxis system. Thus, by studying chemoreceptor localization in E. coli we can establish the rules that will certainly apply, at least in part, to other systems. A second long-term goal is to understand the nature of the polar microenvironment. To date, we have primarily focused on studies in E. coli and in the developmental bacterium, C. crescentus. With the completion of several bacterial genomes, it is now possible to catalog and examine polar proteins using proteomic tools. Parallel studies will be carried out in several bacteria to identify similarities and differences in the polar environments. The results of these studies will provide for a global picture of the bacterial cell pole. The bacterial ribosome is an extremely complicated macromolecular complex whose in vivo biogenesis is poorly understood. Although several bona fide assembly factors have been identified, their precise functions and temporal relationships are not clearly defined.
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