Engineering Diffusion Barriers in the Plasma Membrane - PhD position offered

A PhD position at the Medical University of Vienna (Sitte laboratory) funded by the Austrian Science Fund (FWF) is available to study ";Engineering Diffusion Barriers in the Plasma Membrane". 

The plasma membrane of mammalian cells is not a homogenous matrix for lipids and proteins, but instead organized into micro- and nanostructured domains that control a variety of cellular processes. Various mechanisms were suggested to contribute to this compartmentalization, including the immobilization of membrane proteins via the cytoskeleton, protein-protein interactions, to name a few. One mechanism involves the formation of diffusion barriers via the local enrichment of immobilized membrane proteins as obstacles, which impede the free Brownian motion of other membrane constituents in a size-dependent manner: while lipids and small proteins can easily pass through the obstacle mesh, the passage of large protein complexes is hindered.

Previously, we and others observed oligomerization of neurotransmitter transporters – specifically the serotonin transporter SERT – in a lipid-dependent manner. In addition, there are indications that SERT is not enriched directly in active zones in the neuronal plasma membrane but rather perisynaptically along the membrane of the axon. Together with the known presence of diffusion barriers in the neuronal plasma membrane, this prompted us to hypothesize that SERT mobility and spatial distribution are regulated by diffusion barriers, which allow transit of SERT monomers, but prevent escape of higher order oligomers. Lipid-binding hence could be expected to control both SERT mobility and distribution via controlling SERT oligomerization.  

We propose to combine to a bottom up bio-synthetic approach for generating diffusion barriers to SERT in the plasma membrane of a model cell line with physiological measurements of SERT mobility and spatial distribution in neuronal cells. The PhD candidate would learn how to use state-of-the-art single molecule tracking and single molecule localization microscopy to study the spatiotemporal organization of SERT in the neuronal plasma membrane. Taken together, the project will allow for answering the question of the relevance of diffusion barriers for SERT arrangement in particular, but will also allow for conclusions onto the organization of large membrane protein complexes in general.  

We believe that the combination of a bio-synthetic approach with high-resolution imaging experiments under physiological conditions provides a cutting-edge advantage over alternative, more conventional approaches. The project capitalizes on the expertise of the PIs in micro- and nanopatterning and single molecule/superresolution microscopy (Gerhard J. Schütz), fluorescence resonance energy transfer microscopy and neurotransmitter transporters (Harald H. Sitte).

Applicants should hold a master's degree in biology, biochemistry, physics, or a related discipline, or a doctoral degree in medicine. We are looking for enthusiastic scientists with proficient communication skills, who are good team players. Previous experience with cloning, transfection, cell culture and/or microscopy techniques are advantageous.  

Please send applications (including CV, a letter of motivation describing your scientific interests and contact information of at least two referees) to the address below. 

Name:     Harald H. Sitte

E-Mail:   [email protected]