Regensburg 2013 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Posters: Membranes
BP 9.3: Poster
Montag, 11. März 2013, 17:30–19:30, Poster B2
Cytoskeletal pinning prevents large-scale phase separation in model membranes — •Eugene P. Petrov1,2, Senthil Arumugam1, Jens Ehrig1, and Petra Schwille1,2 — 1Biophysics, BIOTEC, Technische Universität Dresden, 01307 Dresden, Germany — 2Max Planck Institute of Biochemistry, Department of Cellular and Molecular Biophysics, 82152 Martinsried, Germany
One important feature of cell membranes, which has been difficult to recapitulate in the artificial bilayer systems, is the membrane-associated cytoskeleton, which is considered to be one of the reasons for the sub-resolution size of membrane domains. Here we describe a minimal model cytoskeletal network formed by the prokaryotic tubulin homologue, FtsZ. Using giant unilamellar vesicles formed from a quaternary lipid mixture, we demonstrate that, on the one hand, the artificial membrane-associated cytoskeleton suppresses large-scale phase separation below the phase transition temperature, and, on the other hand, preserves phase separation above transition temperature. Our experimental observations support the ideas put forward in our previous simulation study [1]: In particular, the picket-fence effect on phase separation explains why micrometer-scale membrane domains are observed in isolated, cytoskeleton-free giant plasma membrane vesicles, but not in intact cell membranes. The experimentally observed suppression of large-scale phase separation much below the transition temperatures also serves as an argument in favor of the cryoprotective role of the cytoskeleton.
[1] J. Ehrig, E. P. Petrov, P. Schwille, Biophys. J. 100 (2011) 80.