Mesarec Luka, Góźdź Wojciech, Kralj Samo, Fošnarič Miha, Penič Samo, Kralj-Iglič Veronika, Iglič Aleš
Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000, Ljubljana, Slovenia.
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
Eur Biophys J. 2017 Dec;46(8):705-718. doi: 10.1007/s00249-017-1212-z. Epub 2017 May 9.
Biological membranes are composed of different components and there is no a priori reason to assume that all components are isotropic. It was previously shown that the anisotropic properties of membrane components may explain the stability of membrane tubular protrusions even without the application of external force. Our theoretical study focuses on the role of anisotropic membrane components in the stability of membrane tubular structures generated or stabilized by actin filaments. We show that the growth of the actin cytoskeleton inside the vesicle can induce the partial lateral segregation of different membrane components. The entropy of mixing of membrane components hinders the total lateral segregation of the anisotropic and isotropic membrane components. Self-assembled aggregates formed by anisotropic membrane components facilitate the growth of long membrane tubular protrusions. Protrusive force generated by actin filaments favors strong segregation of membrane components by diminishing the opposing effect of mixing entropy.
生物膜由不同成分组成，没有先验理由假定所有成分都是各向同性的。先前的研究表明，即使在没有外力作用的情况下，膜成分的各向异性特性也可以解释膜管状突起的稳定性。我们的理论研究聚焦于各向异性膜成分在由肌动蛋白丝产生或稳定的膜管状结构稳定性中的作用。我们表明，囊泡内肌动蛋白细胞骨架的生长可诱导不同膜成分的部分侧向分离。膜成分混合的熵阻碍了各向异性和各向同性膜成分的完全侧向分离。由各向异性膜成分形成的自组装聚集体促进了长膜管状突起的生长。肌动蛋白丝产生的突出力通过减弱混合熵的相反作用，有利于膜成分的强烈分离。
