Protein over-expression can induce the elongation of cell membrane nanodomains

TL;DR

This study demonstrates that increasing protein concentration in cell membranes causes nanodomains to elongate, with implications for their biological function and potential applications in soft-matter systems.

Contribution

It combines analytical calculations, simulations, and experimental data to reveal how protein levels influence nanodomain shape in membranes, a previously unclear aspect.

Findings

Protein concentration correlates with nanodomain elongation.

Simulations and experiments agree on the elongation effect.

Protein abundance modulates nanodomain shape and function.

Abstract

In cell membranes, proteins and lipids are organized into sub-micrometric nanodomains of varying size, shape and composition, performing specific functions. Despite their biological importance, the detailed morphology of these nanodomains remains unknown. Not only can they hardly be observed by conventional microscopy due to their small size, but there is no full consensus on the theoretical models to describe their structuring and their shapes. Here, we use a combination of analytical calculations and Monte Carlo simulations based upon a model coupling membrane composition and shape to show that increasing protein concentration leads to an elongation of membrane nanodomains. The results are corroborated by Single Particle Tracking measurements on HIV receptors, whose level of expression in the membrane of specifically designed living cells can be tuned. These findings highlight that protein abundance can modulate nanodomain shape and potentially their biological function. Beyond biomembranes, this meso-patterning mechanism is of relevance in several soft-matter systems because it relies on generic physical arguments.