Curvature sensing of curvature-inducing proteins with internal structure

TL;DR

This paper develops a theoretical framework to understand how proteins with asymmetric structures and internal deformations sense membrane curvature, revealing how symmetry and structural features influence their sensing behavior.

Contribution

It introduces a model for curvature sensing by asymmetric and structurally deformed proteins, extending previous symmetric protein models and analyzing their sensing transitions and orientations.

Findings

Mirror symmetric proteins exhibit similar sensing to single-rod proteins.

Asymmetry leads to continuous sensing transitions and metastable states.

Structural deformations induce preferred orientations and enhance sensing.

Abstract

Many types of peripheral and transmembrane proteins can sense and generate membrane curvature. Laterally isotropic proteins and crescent proteins with twofold rotational symmetry, such as Bin/Amphiphysin/Rvs superfamily proteins, have been studied theoretically. However, proteins often have an asymmetric structure or a higher rotational symmetry. We theoretically studied the curvature sensing of proteins with asymmetric structures and structural deformations. First, we examined proteins consisting of two rod-like segments. When proteins have mirror symmetry, their sensing ability is similar to that of single-rod proteins; hence, with increasing protein density on a cylindrical membrane tube, a second- or first-order transition occurs at a middle or small tube radius, respectively. As asymmetry is introduced, this transition becomes a continuous change, and metastable states appear at high protein densities. Protein with threefold, fivefold, or higher rotational symmetry has laterally isotropic bending energy. However, when a structural deformation is allowed, the protein can have a preferred orientation and stronger curvature sensing.