Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139.
Proc Natl Acad Sci U S A. 2014 Jan 7;111(1):143-8. doi: 10.1073/pnas.1310583110. Epub 2013 Dec 12.
Chelatable, mobile forms of divalent zinc, Zn(II), play essential signaling roles in mammalian biology. A complex network of zinc import and transport proteins has evolved to control zinc concentration and distribution on a subcellular level. Understanding the action of mobile zinc requires tools that can detect changes in Zn(II) concentrations at discrete cellular locales. We present here a zinc-responsive, reaction-based, targetable probe based on the diacetyled form of Zinpyr-1. The compound, (6-amidoethyl)triphenylphosphonium Zinpyr-1 diacetate (DA-ZP1-TPP), is essentially nonfluorescent in the metal-free state; however, exposure to Zn(II) triggers metal-mediated hydrolysis of the acetyl groups to afford a large, rapid, and zinc-induced fluorescence response. DA-ZP1-TPP is insensitive to intracellular esterases over a 2-h period and is impervious to proton-induced turn-on. A TPP unit is appended for targeting mitochondria, as demonstrated by live cell fluorescence imaging studies. The practical utility of DA-ZP1-TPP is demonstrated by experiments revealing that, in contrast to healthy epithelial prostate cells, tumorigenic cells are unable to accumulate mobile zinc within their mitochondria.
可螯合的、可移动的二价锌离子（Zn(II)）形式在哺乳动物生物学中发挥着重要的信号作用。一个复杂的锌输入和转运蛋白网络已经进化到可以在亚细胞水平上控制锌的浓度和分布。了解可移动锌的作用需要能够检测离散细胞位置 Zn(II)浓度变化的工具。我们在这里提出了一种基于 Zinpyr-1 的二乙酰化形式的锌响应、基于反应的靶向探针。该化合物，（6-氨乙基）三苯基膦 Zinpyr-1 二乙酸酯（DA-ZP1-TPP）在金属自由状态下基本没有荧光；然而，暴露于 Zn(II)会触发乙酰基的金属介导水解，从而产生大的、快速的、锌诱导的荧光响应。在 2 小时的时间内，DA-ZP1-TPP 对细胞内酯酶不敏感，并且不受质子诱导的开启影响。TPP 单元被附加用于靶向线粒体，如通过活细胞荧光成像研究所示。DA-ZP1-TPP 的实际用途通过实验证明，与健康的上皮前列腺细胞相比，肿瘤细胞无法在其线粒体中积累可移动的锌。
