RT Journal Article
SR Electronic
T1 Genetically encoded ratiometric indicators for potassium ion
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 254383
DO 10.1101/254383
A1 Yi Shen
A1 Sheng-Yi Wu
A1 Vladimir Rancic
A1 Yong Qian
A1 Shin-Ichiro Miyashita
A1 Klaus Ballanyi
A1 Robert E. Campbell
A1 Min Dong
YR 2018
UL http://biorxiv.org/content/early/2018/01/26/254383.abstract
AB Potassium ion (K+) homeostasis and dynamics play critical roles in regulating various biological activities, and the ability to monitor K+ spatial-temporal dynamics is critical to understanding these biological functions. Here we report the design and characterization of a Förster resonance energy transfer (FRET)-based genetically encoded K+ indicator, KIRIN1, constructed by inserting a bacterial cytosolic K+ binding protein (Kbp) between a fluorescent protein (FP) FRET pair, mCerulean3 and cp173Venus. Binding of K+ induces a conformational change in Kbp, resulting in an increase in FRET efficiency. KIRIN1 was able to detect K+ at physiologically relevant concentrations in vitro and is highly selective toward K+ over Na+. We further demonstrated that KIRIN1 allowed real-time imaging of pharmacologically induced depletion of cytosolic K+ in live cells, and KIRIN1 also enabled optical tracing of K+ efflux and reuptake in neurons upon glutamate stimulation in cultured primary neurons. These results demonstrate that KIRIN1 is a valuable tool to detect K+ in vitro and in live cells.