Zinc constitutes the second most abundant transition metal in the human body, and it is implicated in numerous cellular processes, including cell division, DNA and protein synthesis as well as for the catalytic activity of many enzymes. Two major membrane protein families facilitate zinc homeostasis in the animal kingdom, i.e., Zrt/Irt-like proteins (ZIPs aka solute carrier 39, SLC39, family) and Zn transporters (ZnTs), essentially conducting zinc flux in the opposite directions. Human ZIPs (hZIPs) regulate import of extracellular zinc to the cytosol, being critical in preventing overaccumulation of this potentially toxic metal, and crucial for diverse physiological and pathological processes, including development of neurodegenerative disorders and several cancers. To date, our understanding of structure–function relationships governing hZIP-mediated zinc transport mechanism is scarce, mainly due to the notorious difficulty in overproduction of these proteins for biophysical characterization. Here we describe employment of a Saccharomyces cerevisiae-based platform for heterologous expression of hZIPs. We demonstrate that yeast is able to produce four full-length hZIP members belonging to three different subfamilies. One target (hZIP1) is purified in the high quantity and homogeneity required for the downstream biochemical analysis. Our work demonstrates the potential of the described production system for future structural and functional studies of hZIP transporters.

中文翻译：

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用于生物物理表征的酿酒酵母中人类 Zip (SLC39) 锌转运蛋白的过量生产

锌是人体中含量第二丰富的过渡金属，它与许多细胞过程有关，包括细胞分裂、DNA 和蛋白质合成以及许多酶的催化活性。两个主要的膜蛋白家族促进动物界中的锌稳态，即 Zrt/Irt 样蛋白（ZIP 又名溶质载体 39，SLC39，家族）和锌转运蛋白 (ZnT)，基本上以相反的方向传导锌通量。人类 ZIPs (hZIPs) 调节细胞外锌向细胞质的输入，这对于防止这种潜在有毒金属的过度积累至关重要，对多种生理和病理过程至关重要，包括神经退行性疾病和几种癌症的发展。迄今为止，我们对控制 hZIP 介导的锌转运机制的结构 - 功能关系的理解很少，主要是由于这些蛋白质的过度生产难以用于生物物理表征。在这里，我们描述了一个基于酿酒酵母的 hZIP 异源表达平台。我们证明酵母能够产生属于三个不同亚科的四个全长 hZIP 成员。一个目标 (hZIP1) 以下游生化分析所需的高数量和同质性进行纯化。我们的工作证明了所描述的生产系统在 hZIP 转运蛋白的未来结构和功能研究中的潜力。