# Acceleration and suppression of banana-shaped-protein-induced tubulation by addition of small membrane inclusions of isotropic spontaneous curvatures

## TL;DR

This study uses simulations to explore how small membrane inclusions with different curvatures influence banana-shaped protein-induced membrane tubulation, revealing promotion, suppression, and complex interactions affecting membrane morphology.

## Contribution

It demonstrates how isotropic membrane inclusions with varying curvatures modulate protein-induced tubulation, highlighting the cooperative effects of scaffolding proteins and membrane inclusions.

## Key findings

- Isotropic inclusions with positive curvature promote tubulation.
- Opposite curvature inclusions suppress tubulation and induce spherical buds.
- Mixed inclusions initially cancel effects but later accelerate tubulation.

## Abstract

The membrane tubulation induced by banana-shaped protein rods is investigated by using coarse-grained meshless membrane simulations. It is found that the tubulation is promoted by laterally isotropic membrane inclusions that generate the same sign of spontaneous curvature as the adsorbed protein rods. The inclusions are concentrated in the tubules and reduce the bending energy of the tip of the tubules. On the other hand, the inclusions with an opposite curvature suppress the tubulation by percolated-network formation at a high protein-rod density while they induce a spherical membrane bud at a low rod density. When equal amounts of the two types of inclusions (with positive and negative curvatures) are added, their effects cancel each other for the first short period but later the tubulation is slowly accelerated. A positive surface tension suppresses the tubulation. Out results suggest that the cooperation of scaffolding of BAR (Bin/Amphiphysin/Rvs) domains and isotropic membrane inclusions is important for the tubulation.