Theoretical Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan.
MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK, and Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, 606-8501, Japan.
Sci Rep. 2017 Aug 10;7(1):7794. doi: 10.1038/s41598-017-08259-5.
Caveolae are abundant flask-shaped invaginations of plasma membranes that buffer membrane tension through their deformation. Few quantitative studies on the deformation of caveolae have been reported. Each caveola contains approximately 150 caveolin-1 proteins. In this study, we estimated the extent of caveolar deformation by measuring the density of caveolin-1 projected onto a two-dimensional (2D) plane. The caveolin-1 in a flattened caveola is assumed to have approximately one-quarter of the density of the caveolin-1 in a flask-shaped caveola. The proportion of one-quarter-density caveolin-1 increased after increasing the tension of the plasma membrane through hypo-osmotic treatment. The one-quarter-density caveolin-1 was soluble in detergent and formed a continuous population with the caveolin-1 in the caveolae of cells under isotonic culture. The distinct, dispersed lower-density caveolin-1 was soluble in detergent and increased after the application of tension, suggesting that the hypo-osmotic tension induced the dispersion of caveolin-1 from the caveolae, possibly through flattened caveolar intermediates.
小窝是富含质膜的烧瓶状内陷，通过变形缓冲膜张力。关于小窝变形的定量研究很少。每个小窝大约含有 150 个窖蛋白-1 蛋白。在这项研究中，我们通过测量窖蛋白-1在二维（2D）平面上的密度来估计小窝变形的程度。假设在平面化的小窝中，窖蛋白-1的密度约为烧瓶状小窝中窖蛋白-1的四分之一。通过低渗处理增加质膜张力后，四分之一密度的窖蛋白-1的比例增加。四分之一密度的窖蛋白-1在去污剂中是可溶的，并与等渗培养细胞中小窝中的窖蛋白-1形成连续群体。独特的、分散的低密度窖蛋白-1在去污剂中是可溶的，并在施加张力后增加，表明低渗张力诱导窖蛋白-1从小窝中分散，可能通过平面化的小窝中间产物。
