|Class of 2001
Graduated in 2007
|Undergraduate Institution: University of Washington
Major: Physics and Biochemistry
Origin: Seattle, Washington
|Lab: David Zusman
Location: 31 koshland hall
The frz Chemosensory Pathway in Myxococcus xanthus
Myxococcus xanthus is a social bacterium that lives and feeds in groups. In order to accomplish complex processes such as fruiting body formation, rippling and swarming, the cells must sense and respond to signals in their environment by moving in a coordinated and directed manner. M. xanthus cells move on solid surfaces utilizing two distinct motility systems: social (pilus-mediated) and adventurous motility (slime secretion). Locomotion is achieved by cells moving parallel to their long axis and directionality is achieved by reversing periodically. The reversal period is affected by environmental stimuli such as attractants, repellants, and cell density. The frz pathway controls these reversal periods and comprise components homologous to chemotaxis proteins in other bacteria. The core components of the frz pathway are as follows: a receptor (FrzCD), a kinase fusion (FrzE), and a coupling protein (FrzA). FrzF and FrzG are homologous to CheR and CheB and modify the core pathway via methylesterification. It is not clear what FrzE is interacting with (in addition to FrzA) and how this core pathway controls reversal periods in the two motility systems. I am interested in identifying and characterizing components downstream of FrzE in the frz pathway, and elucidating their role in reversal periods i.e. how does the frz pathway regulate extension and retraction of the bipolarly localized pili and slime secretion machinery.
Bacteria were thought of as autonomous creatures until multicelluar behaviors were elucidated such as quorum sensing and biofilm formation. Clearly, cell-cell communication is crucial for multicellular systems to function. M. xanthus participates in behaviors consistent with multicellular organisms that require coordinated and directed motility. In addition, during development, M. xanthus differentiates into at least two cell types making it a model organism to study development. Elucidating the frz pathway will contribute to determining how M. xanthus coordinates to form ordered fruiting bodies. Finally, describing how one chemotaxis pathway can regulate two genetically distinct motility systems will broaden the chemotaxis field.
- Inclán YF, Vlamakis HC, Zusman DR. FrzZ, a dual CheY-like response regulator, functions as an output for the Frz chemosensory pathway of Myxococcus xanthus.Mol Microbiol. 2007 Jul; 65(1):90-102.
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