The accumulation of copper in organisms can lead to altered functions of various pathways and become cytotoxic through the generation of reactive oxygen species. In yeast, cytotoxic metals such as Hg+ , Cd2+ and Cu2+ are transported into the lumen of the vacuole through various pumps. Copper ions are initially transported into the cell by the copper transporter Ctr1 at the plasma membrane and sequestered by chaperones and other factors to prevent cellular damage by free cations. Excess copper ions can subsequently be transported into the vacuole lumen by an unknown mechanism. Transport across membranes requires the reduction of Cu2+ to Cu+ . Labile copper ions can interact with membranes to alter fluidity, lateral phase separation and fusion. Here we found that CuCl2 potently inhibited vacuole fusion by blocking SNARE pairing. This was accompanied by the inhibition of V-ATPase H+ pumping. Deletion of the vacuolar reductase Fre6 had no effect on the inhibition of fusion by copper. This suggests that Cu2+ is responsible for the inhibition of vacuole fusion and V-ATPase function. This notion is supported by the differential effects of chelators. The Cu2+ -specific chelator triethylenetetramine rescued fusion, whereas the Cu+ -specific chelator bathocuproine disulfonate had no effect on the inhibited fusion.

中文翻译：

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铜可阻止V-ATPase活性和SNARE复合物形成，从而抑制酵母液泡融合。

铜在生物体中的积累会导致各种途径的功能发生改变，并通过产生活性氧而变得具有细胞毒性。在酵母中，细胞毒性金属（例如Hg +，Cd2 +和Cu2 +）通过各种泵被运输到液泡腔中。铜离子最初是由铜转运蛋白Ctr1在质膜上转运到细胞中的，并被分子伴侣和其他因素隔离，以防止游离阳离子对细胞的破坏。多余的铜离子随后可以通过未知机制转运到液泡腔中。跨膜运输需要将Cu2 +还原为Cu +。不稳定的铜离子可以与膜相互作用，从而改变流动性，横向相分离和聚变。在这里，我们发现CuCl2通过阻断SNARE配对来有效抑制液泡融合。这伴随着对V-ATPase H +泵送的抑制。液泡还原酶Fre6的缺失对铜的融合抑制没有影响。这表明Cu2 +负责抑制液泡融合和V-ATPase功能。螯合剂的不同作用支持了这一观点。Cu 2+特异性螯合剂三亚乙基四胺拯救了融合，而Cu 2+特异性螯合剂浴铜二磺酸盐对抑制的融合没有影响。