Chernoivanenko Ivan S, Matveeva Elena A, Gelfand Vladimir I, Goldman Robert D, Minin Alexander A
*Institute of Protein Research, Russian Academy of Sciences, Group of Cell Biology, Moscow, Russia; and Department of Cell and Molecular Biology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, USA.
*Institute of Protein Research, Russian Academy of Sciences, Group of Cell Biology, Moscow, Russia; and Department of Cell and Molecular Biology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, USA
FASEB J. 2015 Mar;29(3):820-7. doi: 10.1096/fj.14-259903. Epub 2014 Nov 17.
This study demonstrates that the association of mitochondria with vimentin intermediate filaments (VIFs) measurably increases their membrane potential. This increase is detected by quantitatively comparing the fluorescence intensity of mitochondria stained with the membrane potential-sensitive dye tetramethylrhodamine-ethyl ester (TMRE) in murine vimentin-null fibroblasts with that in the same cells expressing human vimentin (∼35% rise). When vimentin expression is silenced by small hairpin RNA (shRNA) to reduce vimentin by 90%, the fluorescence intensity of mitochondria decreases by 20%. The increase in membrane potential is caused by specific interactions between a subdomain of the non-α-helical N terminus (residues 40 to 93) of vimentin and mitochondria. In rho 0 cells lacking mitochondrial DNA (mtDNA) and consequently missing several key proteins in the mitochondrial respiratory chain (ρ(0) cells), the membrane potential generated by an alternative anaerobic process is insensitive to the interactions between mitochondria and VIF. The results of our studies show that the close association between mitochondria and VIF is important both for determining their position in cells and their physiologic activity.
本研究表明，线粒体与波形蛋白中间丝（VIFs）的结合可显著增加其膜电位。通过定量比较用膜电位敏感染料四甲基罗丹明乙酯（TMRE）染色的小鼠波形蛋白缺失成纤维细胞中线粒体的荧光强度与表达人波形蛋白的相同细胞中线粒体的荧光强度（约升高35%），可检测到这种增加。当通过小发夹RNA（shRNA）使波形蛋白表达沉默以将波形蛋白减少90%时，线粒体的荧光强度降低20%。膜电位的增加是由波形蛋白非α螺旋N端的一个亚结构域（第40至93位氨基酸残基）与线粒体之间的特异性相互作用引起的。在缺乏线粒体DNA（mtDNA）并因此缺失线粒体呼吸链中几种关键蛋白的ρ0细胞中，由替代性厌氧过程产生的膜电位对线粒体与VIF之间的相互作用不敏感。我们的研究结果表明，线粒体与VIF之间的紧密结合对于确定它们在细胞中的位置及其生理活性都很重要。
