Genetically encoded fluorescent indicators for imaging intracellular potassium ion concentration.

ABSTRACT: 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 Ca²⁺ indicator, enable dual-color imaging of K⁺ and Ca²⁺ dynamics in neurons and glial cells. These results demonstrate that KIRIN1 and GINKO1 are useful tools for imaging intracellular K⁺ dynamics.

SUBMITTER: Shen Y 

PROVIDER: S-EPMC6331434 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature