1Department of Urology, Boston Children's Hospital, Department of Microbiology and Immunobiology, Department of Surgery, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 USA.
2Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada.
Commun Biol. 2019 Jan 14;2:18. doi: 10.1038/s42003-018-0269-2. eCollection 2019.
Potassium ion (K) homeostasis and dynamics play critical roles in biological activities. Here we describe three genetically encoded K indicators. KIRIN1 (potassium (K) ion ratiometric indicator) and KIRIN1-GR are Förster resonance energy transfer (FRET)-based indicators with a bacterial K binding protein (Kbp) inserting between the fluorescent protein FRET pairs mCerulean3/cp173Venus and Clover/mRuby2, respectively. GINKO1 (green indicator of K for optical imaging) is a single fluorescent protein-based K indicator constructed by insertion of Kbp into enhanced green fluorescent protein (EGFP). These indicators are suitable for detecting K at physiologically relevant concentrations in vitro and in cells. KIRIN1 enabled imaging of cytosolic K depletion in live cells and K efflux and reuptake in cultured neurons. GINKO1, in conjunction with red fluorescent Ca indicator, enable dual-color imaging of K and Ca dynamics in neurons and glial cells. These results demonstrate that KIRIN1 and GINKO1 are useful tools for imaging intracellular K dynamics.
钾离子（K）的动态平衡在生物活动中起着至关重要的作用。在这里，我们描述了三种遗传编码的 K 指示剂。KIRIN1（钾（K）离子比率指示剂）和 KIRIN1-GR 是基于荧光共振能量转移（FRET）的指示剂，在荧光蛋白 FRET 对 mCerulean3/cp173Venus 和 Clover/mRuby2 之间插入了细菌 K 结合蛋白（Kbp）。GINKO1（用于光学成像的绿色 K 指示剂）是一种基于单荧光蛋白的 K 指示剂，通过将 Kbp 插入增强型绿色荧光蛋白（EGFP）中构建而成。这些指示剂适用于体外和细胞内检测生理相关浓度的 K。KIRIN1 可用于在活细胞中成像细胞溶质 K 耗竭以及培养神经元中的 K 外排和再摄取。GINKO1 与红色荧光 Ca 指示剂结合，可用于在神经元和神经胶质细胞中进行 K 和 Ca 动态的双色成像。这些结果表明，KIRIN1 和 GINKO1 是用于成像细胞内 K 动态的有用工具。
