Degrading a gradient: information transmission in yeast mating

Chemical gradient sensing is ubiquitous in biology. From development to migration, it plays a significant role in both multi-cellular and single-celled organisms. In haploid yeast cells of two types, the detection of chemical gradients is used to find a suitable mating partner. Each mating type secretes a pheromone that is sensed by the partner type. Paradoxically, one of the mating types also secretes an enzyme that degrades the attractant pheromone of its partner type. This degradation is vital for efficient mating. It is thought that degradation leads to a steepened gradient, but the roles of noise and information transmission are poorly understood. Can destroying part of a signal you detect increase the amount of information you receive? Using both stochastic spatiotemporal modeling and tools from information theory, we find that the answer is yes: both the signal-to-noise ratio and information transmission increase with degradation. Our work helps explain a counterintuitive signaling strategy in yeast and offers insights into optimal sensory strategies more generally.

Funding: NSF MCB-2003415