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/2017/04/14/124008.abstract
AB We present in vivo single-cell FRET measurements in the Escherichia coli chemotaxis system that reveal pervasive signaling variability, both across cells in isogenic populations and within individual cells over time. We quantify cell-to-cell variability of adaptation, ligand response, as well as steady-state output level, and analyze the role of network design in shaping this diversity from gene expression noise. In the absence of changes in gene expression, we find that single cells demonstrate strong temporal fluctuations. We provide evidence that such signaling noise can arise from at least two sources: (i) stochastic activities of adaptation enzymes, and (ii) receptor-kinase dynamics in the absence of adaptation. We demonstrate that under certain conditions, (ii) can generate giant fluctuations that drive signaling activity of the entire cell into a stochastic two-state switching regime. Our findings underscore the importance of molecular noise, arising not only in gene expression but also in protein networks.