RT Journal Article SR Electronic T1 Generation and attenuation of variability in a bacterial signaling network revealed by single-cell FRET JF bioRxiv FD Cold Spring Harbor Laboratory SP 124008 DO 10.1101/124008 A1 J.M. Keegstra A1 K. Kamino A1 F. Anquez A1 M.D. Lazova A1 T. Emonet A1 T.S. Shimizu YR 2017 UL http://biorxiv.org/content/early/2017/04/04/124008.abstract AB We present in vivo single-cell FRET measurements in the Escherichia coli chemotaxis system that reveal the influence of network design on noise-induced variability, both across cells in isogenic populations and within individual cells over time. We find pervasive cell-to-cell variability in ligand-response sensitivity, adaptation timescale, as well as the steady-state set point of network output, and analyze the role of network parameters and topology in shaping this diversity. In the absence of ligand stimulation or changes in gene expression, we observe temporal fluctuations in the intracellular signal attributable to stochastic activities of adaptation enzymes CheR and CheB, with unexpectedly large amplitudes (>2-fold previous estimates). Our results demonstrate how signaling networks can tune population diversity and temporal variability by either amplifying or suppressing molecular noise, arising not only in gene expression processes but also in stochastic protein-protein interactions.