Mesarec Luka, Góźdź Wojciech, Iglič Veronika Kralj, Kralj Samo, Iglič Aleš
Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia.
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Colloids Surf B Biointerfaces. 2016 May 1;141:132-140. doi: 10.1016/j.colsurfb.2016.01.010. Epub 2016 Jan 21.
Membrane deformations induced by attached BAR superfamily domains could trigger or facilitate the growth of plasma membrane protrusions. The BAR domain family consists of BAR, F-BAR and I-BAR domains, each enforcing a different local curvature when attached to the membrane surface. Our theoretical study mainly focuses on the role of I-BAR in the membrane tubular deformations generated or stabilised by actin filaments. The influence of the area density of membrane attached BAR domains and their intrinsic curvature on the closed membrane shapes (vesicles) was investigated numerically. We derived an analytical approximative expression for the critical relative area density of BARs at which the membrane tubular protrusions on vesicles are most prominent. We have shown that the BARs with a higher intrinsic curvature induce thinner and longer cylindrical protrusions. The average orientation of the membrane attached BARs is altered when the vesicle shape is subjected to external force of growing actin rod-like structure inside a vesicle. The average orientation angle of membrane attached BARs may indicate whether the actin filaments are just stabilising the protrusion or generating it by stretching the vesicle.
附着的BAR超家族结构域诱导的膜变形可触发或促进质膜突起的生长。BAR结构域家族由BAR、F-BAR和I-BAR结构域组成，当附着于膜表面时，每个结构域都会施加不同的局部曲率。我们的理论研究主要关注I-BAR在由肌动蛋白丝产生或稳定的膜管状变形中的作用。数值研究了附着在膜上的BAR结构域的面积密度及其固有曲率对封闭膜形状（囊泡）的影响。我们推导了一个解析近似表达式，用于计算囊泡上膜管状突起最突出时BARs的临界相对面积密度。我们已经表明，具有较高固有曲率的BARs会诱导出更细更长的圆柱形突起。当囊泡形状受到囊泡内生长的肌动蛋白棒状结构的外力作用时，附着在膜上的BARs的平均取向会发生改变。附着在膜上的BARs的平均取向角可能表明肌动蛋白丝是仅仅稳定突起还是通过拉伸囊泡来产生突起。
