Single cells can resolve graded stimuli

TL;DR

Single cells can transmit over 2 bits of information about graded stimuli through the ERK pathway, revealing their ability to resolve stimulus intensity despite population heterogeneity and low population-level information.

Contribution

This study demonstrates that individual cells can encode detailed information about stimuli, contrasting with previous population-level measurements that suggested low information transmission.

Findings

Single cells transmit over 2 bits of information.

Population heterogeneity is significant in ERK responses.

Single-cell resolution reveals more information than population averages.

Abstract

Cells use signalling pathways as windows into the environment to gather information, transduce it into their interior, and use it to drive behaviours. MAPK (ERK) is a highly conserved signalling pathway in eukaryotes, directing multiple fundamental cellular behaviours such as proliferation, migration, and differentiation, making it of few central hubs in the signalling circuitry of cells. Despite this versatility of behaviors, population-level measurements have reported low information content (\textless 1 bit) relayed through the ERK pathway, rendering the population barely able to distinguish the presence or absence of stimuli. Here, we contrast the information transmitted by a single cell and a population of cells. Using a combination of optogenetic experiments, data analysis based on information theory framework, and numerical simulations we quantify the amount of information transduced from the receptor to ERK, from responses to singular, brief and sparse input pulses. We show that single cells are indeed able to resolve between graded stimuli, yielding over 2 bit of information, however showing a large population heterogeneity.