Dresden 2017 – scientific programme
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BP: Fachverband Biologische Physik
BP 48: Membranes and Vesicles II
BP 48.1: Invited Talk
Thursday, March 23, 2017, 09:30–10:00, HÜL 386
Shaping membranes: ENTH activity as a function of membrane tension — •Claudia Steinem1, Martin Gleisner1, Benjamin Kroppen2, Nelli Teske1, Andreas Janshoff3, and Michael Meinecke2 — 1Institute of Organic and Biomolecular Chemistry, University of Göttingen, Germany, — 2Department of Cellular Biochemistry, University of Göttingen, Germany — 3Institute of Physical Chemistry, University of Göttingen, Germany
One of the early players of the process of clathrin-mediated endocytosis is the protein epsin. The epsin N-terminal homology domain (ENTH) binds to PtdIns(4,5)P2 resulting in tubulation as a result of membrane bending. This process is highly sensitive to the lateral membrane tension σ. By means of protruded pore-spanning membranes (PSMs, σ = 2 mN/m) and adhered giant unilamellar vesicles (GUVs, σ = 0.1-1 mN/m), we analyzed how ENTH binding alters membrane tension and whether membrane tubules are formed. Binding of ENTH to PtdIns(4,5)P2-doped protruded PSMs resulted in a growth of the protrusions, which indicates a reduction of the membrane tension. Tubulation was not observed. At low membrane tension of adhered GUV, ENTH binding induced tubular structures, while at higher membrane tension, ENTH interaction only led to a flattening of the GUVs. GUV flattening was attributed to an increased surface area caused by the insertion of the ENTH helix-0 into the membrane. Our results demonstrate that ENTH is capable of reducing the lateral membrane tension, which makes membrane bending energetically less costly.