Increased accuracy of ligand sensing by receptor diffusion on cell surface

TL;DR

This paper demonstrates that lateral diffusion of receptors on cell surfaces enhances the accuracy of ligand sensing, with implications for neural synapse function and neurotransmission.

Contribution

It provides a quantitative analysis linking receptor diffusion to sensing accuracy, highlighting differences between AMPA and NMDA receptors in neural communication.

Findings

Receptor diffusion improves sensing accuracy for ligand detection.

AMPA receptors have higher sensing accuracy than NMDA receptors.

Receptor diffusion's role varies with receptor function in neurotransmission.

Abstract

The physical limit with which a cell senses external ligand concentration corresponds to the perfect absorber, where all ligand particles are absorbed and overcounting of same ligand particles does not occur. Here we analyze how the lateral diffusion of receptors on the cell membrane affects the accuracy of sensing ligand concentration. Specifically, we connect our modeling to neurotransmission in neural synapses where the diffusion of glutamate receptors is already known to refresh synaptic connections. We find that receptor diffusion indeed increases the accuracy of sensing for both the glutamate AMPA and NDMA receptors, although the NMDA receptor is overall much noiser. We propose that the difference in accuracy of sensing of the two receptors can be linked to their different roles in neurotransmission. Specifically, the high accuracy in sensing glutamate is essential for the AMPA receptor to start membrane depolarization, while the NMDA receptor is believed to work in a second stage as a coincidence detector, involved in long-term potentiation and memory.