Institut National de la Recherche Scientifique, Centre Eau Terre Environnement, 490, rue de la Couronne, Québec, QC, G1K 9A9, Canada.
EcotoQ, 490, rue de la Couronne, Québec, QC, G1K 9A9, Canada.
Metallomics. 2022 Jun 22;14(6). doi: 10.1093/mtomcs/mfac033.
Copper (Cu) is a redox-active transition element critical to various metabolic processes. These functions are accomplished in tandem with Cu-binding ligands, mainly proteins. The main goal of this work was to understand the mechanisms that govern the intracellular fate of Cu in the freshwater green alga, Chlamydomonas reinhardtii, and more specifically to understand the mechanisms underlying Cu detoxification by algal cells in low-Fe conditions. We show that Cu accumulation was up to 51-fold greater for algae exposed to Cu in low-Fe medium as compared to the replete-Fe growth medium. Using the stable isotope 65Cu as a tracer, we studied the subcellular distribution of Cu within the various cell compartments of C. reinhardtii. These data were coupled with metallomic and proteomic approaches to identify potential Cu-binding ligands in the heat-stable proteins and peptides fraction of the cytosol. Cu was mostly found in the organelles (78%), and in the heat-stable proteins and peptides (21%) fractions. The organelle fraction appeared to also be the main target compartment of Cu accumulation in Fe-depleted cells. As Fe levels in the medium were shown to influence Cu homeostasis, we found that C. reinhardtii can cope with this additional stress by utilizing different Cu-binding ligands. Indeed, in addition to expected Cu-binding ligands such as glutathione and phytochelatins, 25 proteins were detected that may also play a role in the Cu-detoxification processes in C. reinhardtii. Our results shed new light on the coping mechanisms of C. reinhardtii when exposed to environmental conditions that induce high rates of Cu accumulation.
铜 (Cu) 是一种氧化还原活性的过渡元素，对各种代谢过程至关重要。这些功能与 Cu 结合配体（主要是蛋白质）协同完成。这项工作的主要目的是了解控制淡水绿藻莱茵衣藻细胞内 Cu 命运的机制，更具体地说，是了解藻类细胞在低铁条件下解毒 Cu 的机制。我们表明，与在富含铁的生长培养基中暴露于 Cu 的藻类相比，在缺铁培养基中暴露于 Cu 的藻类的 Cu 积累量高达 51 倍。我们使用稳定同位素 65Cu 作为示踪剂，研究了 Cu 在莱茵衣藻各个细胞区室中的亚细胞分布。这些数据与金属组学和蛋白质组学方法相结合，鉴定了细胞溶质中热稳定蛋白和肽部分中潜在的 Cu 结合配体。Cu 主要存在于细胞器（78%）和热稳定蛋白和肽（21%）部分。细胞器部分似乎也是铁耗尽细胞中 Cu 积累的主要靶区室。由于培养基中的 Fe 水平会影响 Cu 动态平衡，我们发现莱茵衣藻可以通过利用不同的 Cu 结合配体来应对这种额外的压力。事实上，除了预期的 Cu 结合配体如谷胱甘肽和植物螯合肽外，还检测到 25 种可能在莱茵衣藻 Cu 解毒过程中发挥作用的蛋白质。我们的结果为莱茵衣藻在暴露于诱导 Cu 高积累的环境条件下的应对机制提供了新的认识。
