Signal focusing through active transport

TL;DR

This paper demonstrates that active transport of signaling molecules in cells reduces noise and enhances sensing precision, aligning with biological observations and informing diagnostic device design.

Contribution

It introduces a mechanism where active transport improves molecular sensing accuracy by reducing noise correlation time, a novel insight into cellular signaling.

Findings

Active transport reduces noise correlation time.

Enhanced sensing precision through active focusing.

Compatibility with biological cell observations.

Abstract

In biological cells and novel diagnostic devices biochemical receptors need to be sensitive to extremely small concentration changes of signaling molecules. The accuracy of such molecular signaling is ultimately limited by the counting noise imposed by the thermal diffusion of molecules. Many macromolecules and organelles transiently bind to molecular motors and are then actively transported. We here show that a random albeit directed delivery of signaling molecules to within a typical diffusion distance to the receptor reduces the correlation time of the counting noise, effecting an improved sensing precision. The conditions for this active focusing are indeed compatible with observations in living cells. Our results are relevant for a better understanding of molecular cellular signaling and the design of novel diagnostic devices.