High-Performance Genetically Encoded Green Fluorescent Biosensors for Intracellular <scp>l</scp>-Lactate

Abstract

l-Lactate is a monocarboxylate produced during the process of cellular glycolysis and has long generally been considered a waste product. However, studies in recent decades have provided new perspectives on the physiological roles of l-lactate as a major energy substrate and a signaling molecule. To enable further investigations of the physiological roles of l-lactate, we have developed a series of high-performance (Δ<i>F</i>/<i>F</i> = 15 to 30 <i>in vitro</i>), intensiometric, genetically encoded green fluorescent protein (GFP)-based intracellular l-lactate biosensors with a range of affinities. We evaluated these biosensors in cultured cells and demonstrated their application in an <i>ex vivo</i> preparation of <i>Drosophila</i> brain tissue. Using these biosensors, we were able to detect glycolytic oscillations, which we analyzed and mathematically modeled.