Scaffold number in yeast signaling system sets tradeoff between system output and dynamic range

TY M. THOMSON; KIRSTEN R. BENJAMIN; ALAN BUSH; TONYA LOVE; DAVID PINCUS; ORNA RESNEKOV; RICHARD C. YU; ANDREW GORDON; ALEJANDRO COLMAN-LERNER; DREW ENDY; ROGER BRENT

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2011 vol. 108 p. 20265 - 20270

0027-8424

Although the proteins comprising many signaling systems are known, less is known about their numbers per cell. Existing measurements often vary by more than 10-fold. Here, we devised improved quantification methods to measure protein abundances in the Saccharomyces cerevisiae pheromone response pathway, an archetypical signaling system. These methods limited variation between independent measurements of protein abundance to a factor of two. We used these measurements together with quantitative models to identify and investigate behaviors of the pheromone response system sensitive to precise abundances. The difference between the maximum and basal signaling output (dynamic range) of the pheromone response MAPK cascade was strongly sensitive to the abundance of Ste5, the MAPK scaffold protein, and absolute system output depended on the amount of Fus3, the MAPK. Additional analysis and experiment suggest that scaffold abundance sets a tradeoff between maximum system output and system dynamic range, a prediction supported by recent experiments.