University of Notre Dame/Interdisciplinary Center for the Study of Biocomplexity/Center News

Jim Keener
University of Utah
A Model for Length Control of Flagellar Hooks of Salmonella Typhimurium

The construction of flagellar motors is a carefully regulated genetic process. Among the structures that are built is a U-joint-like structure called the hook. The length of the hook is

tightly regulated.

The question that will be addressed in this talk is how Salmonella detects and regulates the length of these structures. This is related to the more general question of how physical properties (such as size or length) can be detected by chemical signals and what those mechanisms are.

In this talk, I will present mathematical models for the length regulation of the hook structure by Salmonella Typhimurium. Some of the details are as follows: Under the assumption that the molecular constituents are translocated into the nascent filament by an ATP-ase and then move by molecular diffusion to the growing end, where they polymerize into the growing tube, we find

that there is a detectable transition from secretion limited growth to diffusion limited growth. We propose that this transition can be detected by the secretant FliK, allowing FliK to interact with FlhB thereby changing the secretion target of the type III secretion machinery and terminating the growth of the hook.


	Jim Keener University of Utah A Model for Length Control of Flagellar Hooks of Salmonella Typhimurium The construction of flagellar motors is a carefully regulated genetic process. Among the structures that are built is a U-joint-like structure called the hook. The length of the hook is tightly regulated. The question that will be addressed in this talk is how Salmonella detects and regulates the length of these structures. This is related to the more general question of how physical properties (such as size or length) can be detected by chemical signals and what those mechanisms are. In this talk, I will present mathematical models for the length regulation of the hook structure by Salmonella Typhimurium. Some of the details are as follows: Under the assumption that the molecular constituents are translocated into the nascent filament by an ATP-ase and then move by molecular diffusion to the growing end, where they polymerize into the growing tube, we find that there is a detectable transition from secretion limited growth to diffusion limited growth. We propose that this transition can be detected by the secretant FliK, allowing FliK to interact with FlhB thereby changing the secretion target of the type III secretion machinery and terminating the growth of the hook.

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