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Dr. Roland Knorr
Gruppenleiter
Telefon:+49 331 567-9668Fax:+49 331 567-9612

Dynamics of Bio-Membranes

The goal of our group is to understand the dynamics and regulation of biological membranes. We will identify new mechanisms of shape regulation of cellular organelles by unique combinations of various experimental approaches at the interface between biochemistry and biophysics.

<p>1) 3D models of an intermediate step of autophagosome formation</p>

1) 3D models of an intermediate step of autophagosome formation

Our focus is autophagy, a conserved major cellular degradation pathway implicated in severe diseases such as cancer or neurodegenerative disorders like Alzheimer and Parkinson  as well as essential during normal development. During autophagy, a membrane bound organelle, the autophagosome, is generated de novo. The remodeling of the autophagic membrane during the lifecycle of the organelle is a complex multistep process and involves several changes in the topology of the autophagic membrane. Recently we could unravel some of the autophagosomes secrets (Knorr et al DOI:10.1371/journal.pone.0032753, DOI: 10.1371/journal.pone.0115357, DOI:10.1080/15548627.2015.1091552.

Some of the essential but open questions in the field include: 1) Which membrane sources are essential for autophagy? 2) What is the minimal system for autophagosome formation? 3) How do autophagosomes close?

Our group focuses on lipid membranes with sizes in the micrometer range, so called giant vesicles (GUVs). Such membranes can be easily observed and manipulated with optical microscopes. Moreover they offer the chance to apply a wide range of advanced microscopy techniques including two-photon excitation and STED. Our lab offers you a broad range of excellent techniques and methodologies with cutting edge microscopy facilities and is embedded within a theoretical department. This offers the unique possibility to iterate between experiment and theory. The institute is a very international, multi-disciplinary environment that encourages close collaborations between groups with different expertise and is located in the greater Berlin/Brandenburg area, which provides a rich scientific environment.

Methods available in the group:

  • Protein and lipid biochemistry
  • Microfluidic chambers
  • Cell culture
  • Biomimetic systems of cellular membranes such as lipid vesicles (GUVs, SUVs) and planar model systems (SLBs, monolayers) from natural and well as synthetic lipids
  • Model systems which build nano- and microstructures by 2D or 3D phase separation which are similar to fluid lipid domains (lipid rafts in cellular membranes) or aqueous two phase systems
  • Microscopy and STED-Nanoscopy with strong focus on fluorescence microscopy (including confocal one- and two-photon excitation, measurements of the fluorescence lifetime and signal correlation)
<p>2) Some impression from the lab: gel-GUVs during electric pulses, “cryptic, fluid domains”, protein-GFP droplets originating form a fluid-fluid phase separation on glass and supported bilayers (red), degenerated protein droplets, part of a microfluidic design filled with a dye</p>

2) Some impression from the lab: gel-GUVs during electric pulses, “cryptic, fluid domains”, protein-GFP droplets originating form a fluid-fluid phase separation on glass and supported bilayers (red), degenerated protein droplets, part of a microfluidic design filled with a dye

Cooperation partners:

  • Y. Ohsumi & H. Nakatogawa, Tokio Institute of Technology/ Japan
  • A. Hyman & T. Franzmann, MPI of Molecular Cell Biology and Genetics Dresden/Germany
  • N. Mizushima, The University of Tokyo/Japan
  • N. Noda, Microbial Chemistry Research Foundation, Tokyo/Japan
  • K.Riske, Universidade Federal de Sao Paulo/ Brasilien

Applications of talented and enthusiastic students and scientist are very welcome. Please send your application documents to the address below. Please include a short letter (max. 1 page) focusing on your motivation to apply in our “Bio-Membrane Dynamics” group, pointing out the key questions you are interested in and methods you would like to apply.

 
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