A Cellular System for Spatial Signal Decoding in Chemical Gradients

Björn Hegemann, Michael Unger, Sung Sik Lee, Ingrid Stoffel-Studer, Jasmin van den Heuvel, Serge Pelet, Heinz Koeppl, Matthias Peter
2015 Developmental Cell  
Graphical Abstract Highlights d The site of polarity establishment is selected independently of gradient direction d A mobile polarity complex is guided toward the gradient prior to polarized growth d Site mobility requires restricting Cdc42 activity through Cdc24 nuclear sequestration d Fus3 sets Cdc24 sequestration to switch from site mobility to polarized growth SUMMARY Directional cell growth requires that cells read and interpret shallow chemical gradients, but how the gradient directional
more » ... information is identified remains elusive. We use single-cell analysis and mathematical modeling to define the cellular gradient decoding network in yeast. Our results demonstrate that the spatial information of the gradient signal is read locally within the polarity site complex using double-positive feedback between the GTPase Cdc42 and trafficking of the receptor Ste2. Spatial decoding critically depends on low Cdc42 activity, which is maintained by the MAPK Fus3 through sequestration of the Cdc42 activator Cdc24. Deregulated Cdc42 or Ste2 trafficking prevents gradient decoding and leads to mis-oriented growth. Our work discovers how a conserved set of components assembles a network integrating signal intensity and directionality to decode the spatial information contained in chemical gradients. 458 Developmental Cell 35, 458-470, November 23, 2015 ª2015 Elsevier Inc.
doi:10.1016/j.devcel.2015.10.013 pmid:26585298 fatcat:7oyjinomavhh5kabbkmla7y2wa