KC Huang

Department of Bioengineering, Stanford University

Jueves 26/11/2009, 14 hs
Aula Federman, 1er piso, Pabellón I 

In the past decade, fluorescence microscopy has fashioned a new appreciation for the diversity of ways in which proteins and lipids organize and segregate on ba cterial membranes. Though some targeting anchors are known, cellular symmetry br eaking ultimately requires molecular components that self-organize. In this talk , I will describe physical mechanisms for self-organized polar localization. The remarkable accuracy of cell division in E. coli and related bacteria is partial ly regulated by the Min-protein system, which prevents division near the cell en ds by oscillating spatially from pole to pole. We have developed a model of the Min system, using only known properties of the proteins, which accurately reproduces the observed oscillations in both rod-shap ed and round cells. In particular, we have shown that Min-protein oscillations c an select the long axis in nearly round cells, a potentially important factor in division-plane selection in round bacteria such as Neisseria gonnorhoeae. These results suggest that oscillations may provide a general mechanism by which prot eins can localize in response to features of cell geometry incapable of localizi ng individual molecules.