NSF Postdoctoral Fellowship in Biology FY 2012

Oliver Piercen M, Bethlehem PA

Investigators

Abstract

Studying the influence of membrane curvature on positioning lipids and proteins in bacterial membranes Many proteins in bacteria are preferentially located at specific sites within the cell. These proteins can control anything from cell shape, growth, division, movement of intracellular components, or assembly of motility systems to cell polarization. An untested hypothesis is that microdomains of a uniquely-curved phospholipid, cardiolipin, function as 'landmarks' to localize proteins in bacteria at regions of high negative curvature via a mechanism similar to lipid rafts. The aim of this proposal is to determine the relationship between the localization of CL microdomains, protein localization, and membrane curvature using spheroplasts of Escherichia coli, giant unilamellar vesicles (GUVs), and supported lipid bilayers (SLBs). By compressing spheroplasts and GUVs in microfluidic channels, or by conforming SLBs to either micropatterned curvy substrates or subject to deformation over a micropore, the temporal and spatial organization of CL and its putative binding proteins can be measured. An understanding of the reorganization of lipid microdomains in response to membrane curvature will be critical in developing a complete picture of the physical forces that influence biomolecule localization in bacteria. It is envisioned that the strain induced reorganization of membranes may be a widely spread phenomenon in biology that extends to eukaryotes. Training objectives include developing an expertise in bacterial lipid metabolism and its quantification by in vivo labeling or through in vitro analysis. Broader impacts of this work include educational outreach through the Research Experience for Teaching Program. The PI will mentor local teachers by developing educational kits that will be incorporated into after-school programs in the Madison Metropolitan School District through the MicroExplorers Program.