title: Improved molecular toolkit for cAMP studies in live cells.
abstract: BACKGROUND
  cAMP is a ubiquitous second messenger involved in a wide spectrum of cellular processes including gene transcription, cell proliferation, and axonal pathfinding. Precise spatiotemporal manipulation and monitoring in live cells are crucial for investigation of cAMP-dependent pathways, but existing tools have several limitations.
  
  
  RESULTS
  We have improved the suitability of cAMP manipulating and monitoring tools for live cell imaging. We attached a red fluorescent tag to photoactivated adenylyl cyclase (PACα) that enables reliable visualization of this optogenetic tool for cAMP manipulation in target cells independently of its photoactivation. We show that replacement of CFP/YFP FRET pair with GFP/mCherry in the Epac2-camps FRET probe reduces photobleaching and stabilizes the noise level during imaging experiments.
  
  
  CONCLUSIONS
  The modifications of PACα and Epac2-camps enhance these tools for in vitro cAMP studies in cultured living cells and in vivo studies in live animals in a wide range of experiments, and particularly for long term time-lapse imaging.
authors.affiliation: Neurobiology Section, Division of Biological Sciences, Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093, USA. xavier.nicol@inserm.fr.
authors.forename: Kwan Pyo
authors.initials: KP
authors.lastname: Hong
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Spitzer
authors.forename: Xavier
authors.initials: X
authors.lastname: Nicol