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TitleGenetically encoded fluorescent indicators for imaging intracellular potassium ion concentration.
Publication TypeJournal Article
Year of Publication2019
AuthorsShen, Yi, Sheng-Yi Wu, Vladimir Rancic, Abhi Aggarwal, Yong Qian, Shin-Ichiro Miyashita, Klaus Ballanyi, Robert E. Campbell, and Min Dong
JournalCommun Biol
Date Published2019

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.

Alternate JournalCommun Biol
PubMed ID30652129
PubMed Central IDPMC6331434