Genetically Encoded Fluorescent Biosensors to Explore AMPK Signaling and Energy Metabolism
Maintenance of energy homeostasis is a basic requirement for cell survival. Different mechanisms have evolved to cope with spatial and temporal mismatch between energy-providing and -consuming processes. Among these, signaling by AMP-activated protein kinase (AMPK) is one of the key players, regulated by and itself regulating cellular adenylate levels. Further understanding its complex cellular function requires deeper insight into its activation patterns in space and time at a single cell level. This may become possible with an increasing number of genetically encoded fluorescent biosensors, mostly based on fluorescence resonance energy transfer, which have been engineered to monitor metabolic parameters and kinase activities. Here, we review basic principles of biosensor design and function and the advantages and limitations of their use and provide an overview on existing FRET biosensors to monitor AMPK activation, ATP concentration, and ATP/ADP ratios, together with other key metabolites and parameters of energy metabolism.
KeywordsAMPK Activation Green Fluorescent Protein Fluorescence Recognition Element AMPK Signaling Cellular Energy State
This work was supported by a grant from the Region Rhône Alpes, France (to U.S. and I.B.). Initial experiments of the authors on FRET sensors were supported among others by the EU 6th framework programs (contract LSHM-CT-2004-005272 EXGENESIS), Fondation ARC R2012 (CA 25/09/2014), and the Agence Nationale de Recherche (France, chaire d’excellence to U.S.).
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