Grossmann Guido, Opekarová Miroslava, Malinsky Jan, Weig-Meckl Ina, Tanner Widmar
University of Regensburg, Cell Biology and Plant Physiology, Regensburg, Germany.
EMBO J. 2007 Jan 10;26(1):1-8. doi: 10.1038/sj.emboj.7601466. Epub 2006 Dec 14.
The plasma membrane potential is mainly considered as the driving force for ion and nutrient translocation. Using the yeast Saccharomyces cerevisiae as a model organism, we have discovered a novel role of the membrane potential in the organization of the plasma membrane. Within the yeast plasma membrane, two non-overlapping sub-compartments can be visualized. The first one, represented by a network-like structure, is occupied by the proton ATPase, Pma1, and the second one, forming 300-nm patches, houses a number of proton symporters (Can1, Fur4, Tat2 and HUP1) and Sur7, a component of the recently described eisosomes. Evidence is presented that sterols, the main lipid constituent of the plasma membrane, also accumulate within the patchy compartment. It is documented that this compartmentation is highly dependent on the energization of the membrane. Plasma membrane depolarization causes reversible dispersion of the H(+)-symporters, not however of the Sur7 protein. Mitochondrial mutants, affected in plasma membrane energization, show a significantly lower degree of membrane protein segregation. In accordance with these observations, depolarized membranes also considerably change their physical properties (detergent sensitivity).
质膜电位主要被视为离子和营养物质转运的驱动力。以酿酒酵母作为模式生物，我们发现了膜电位在质膜组织中的新作用。在酵母质膜内，可以观察到两个不重叠的亚区室。第一个以网络状结构为代表，由质子ATP酶Pma1占据，第二个形成300纳米的斑块，容纳许多质子同向转运体（Can1、Fur4、Tat2和HUP1）以及Sur7，Sur7是最近描述的eisosomes的一个组成部分。有证据表明，作为质膜主要脂质成分的固醇也在斑块状区室中积累。据记载，这种区室化高度依赖于膜的能量化。质膜去极化导致H(+)同向转运体可逆性分散，但Sur7蛋白不会。影响质膜能量化的线粒体突变体显示出膜蛋白分离程度显著降低。与这些观察结果一致，去极化的膜也会显著改变其物理性质（去污剂敏感性）。
