Regensburg 2007 – scientific programme
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BP: Fachverband Biologische Physik
BP 3: Membranes and Interfaces
BP 3.6: Talk
Monday, March 26, 2007, 15:30–15:45, H43
Shape and fluctuations of biphasic membrane vesicles — •Stefan Semrau1, Timon Idema2, Cornelis Storm2, and Thomas Schmidt1 — 1Physics of life processes, Leiden institute of physics, Leiden university, The Netherlands — 2Theoretical biophysics, Lorentz institute, Leiden university, The Netherlands
Heterogeneities in the cell membrane due to coexisting lipid phases have been conjectured to play a major functional role in cell signaling and traffic. Purely physical properties of such multiphase systems, such as the line tension and the bending moduli, are crucially involved in endocytocis and lipid trafficking, and determine the kinetics and asymptotics of phase separation. We have developed an analytical description of the vesicle shape of weakly budded biphasic vesicles and shown it to be in excellent agreement with numerical calculations and experiments. Our description allows for a reproducible and reliable systematic determination of the physical parameters of the membrane in the biologically relevant limit of weakly budded shapes. The parameters thus obtained allow us to determine an upper bound for the size of nanodomains in the plasma membrane of living cells.