The goal of this proposal is to achieve a detailed understanding of a key step in the sporulation of Bacillus subtilis, engulfment. During engulfment the edges of the sporulation septum migrate around and fully enclose the forespore; ultimately the forespore is fully enclosed within the mother cell cytoplasm and is surrounded by two membranes. Engulfment is essential for both spore morphogenesis and for full activation of late sporulation-specific transcription factors in both cells of the developing sporangium. Although several sporulation-specific proteins have been implicated in engulfment, its mechanism remains obscure. Bacterial cells lack the cytoskeletal proteins associated with similar eukaryotic events, and hence must use a noval mechanism to drive the engulfment of one cell by another. We will use the following specific aims to further our understanding of engulfment: Characterization of the known engulfment proteins to determine their subcellular distribution, to identify proteins with which they interact, to determine their biochemical activities, and to more precisely determine the stage at which they are required for engulfment. Identification of additional proteins required for engulfment, using both genetic and biochemical approaches. The development of a system to observe engulfment in living bacteria, using video microscopy and protein fusions to the green fluorescent protein (GFP) of Aquoria victoria. It is hoped that by identifying a large number of proteins required for engulfment, and by studying their biochemical activities, interactions and subcellular distributions, that we can begin to understand the mechanism by which one bacterial cell can engulf another. Engulfment provides a unique model system for the study of regulated membrane movements in bacteria.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM057045-04
Application #
6343003
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Greenberg, Judith H
Project Start
1998-01-01
Project End
2002-12-31
Budget Start
2001-01-01
Budget End
2001-12-31
Support Year
4
Fiscal Year
2001
Total Cost
$197,131
Indirect Cost
Name
University of California San Diego
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Riley, Eammon P; Trinquier, Aude; Reilly, Madeline L et al. (2018) Spatiotemporally regulated proteolysis to dissect the role of vegetative proteins during Bacillus subtilis sporulation: cell-specific requirement of ?H and ?A. Mol Microbiol 108:45-62
Lopez-Garrido, Javier; Ojkic, Nikola; Khanna, Kanika et al. (2018) Chromosome Translocation Inflates Bacillus Forespores and Impacts Cellular Morphology. Cell 172:758-770.e14
Chaikeeratisak, Vorrapon; Nguyen, Katrina; Khanna, Kanika et al. (2017) Assembly of a nucleus-like structure during viral replication in bacteria. Science 355:194-197
Miller, Marina; Tam, Arvin B; Mueller, James L et al. (2017) Cutting Edge: Targeting Epithelial ORMDL3 Increases, Rather than Reduces, Airway Responsiveness and Is Associated with Increased Sphingosine-1-Phosphate. J Immunol 198:3017-3022
Lamsa, Anne; Lopez-Garrido, Javier; Quach, Diana et al. (2016) Rapid Inhibition Profiling in Bacillus subtilis to Identify the Mechanism of Action of New Antimicrobials. ACS Chem Biol 11:2222-31
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Sahonero-Canavesi, Diana X; Sohlenkamp, Christian; Sandoval-Calderón, Mario et al. (2015) Fatty acid-releasing activities in Sinorhizobium meliloti include unusual diacylglycerol lipase. Environ Microbiol 17:3391-406
Yen Shin, Jae; Lopez-Garrido, Javier; Lee, Sang-Hyuk et al. (2015) Visualization and functional dissection of coaxial paired SpoIIIE channels across the sporulation septum. Elife 4:e06474
Ojkic, Nikola; López-Garrido, Javier; Pogliano, Kit et al. (2014) Bistable forespore engulfment in Bacillus subtilis by a zipper mechanism in absence of the cell wall. PLoS Comput Biol 10:e1003912

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