Galactocerebroside Lipid Nanotubes, a Model Membrane System for Studying Membrane-Associated Proteins on a Molecular Scale

Abstract

Galactocerebroside lipid nanotubes are membrane-mimicking systems for studying the function and structure of proteins involved in membrane shape remodeling, such as in intracellular trafficking, cell division, and migration or involved in the formation of membrane contact sites. They exhibit a constant and small diameter of 30 nm and a length of up to 2 μm. They can be functionalized with lipid ligands, providing a large binding surface for protein without membrane shape remodeling. These features make it possible to study protein assemblies on membranes different from those accessible with vesicular systems. This chapter describes the process of galactocerebroside nanotube formation, the incorporation of different lipid ligands, factors influencing protein binding, and the experimental conditions for their use in flotation assay and imaging by transmission electron and cryo-electron microscopy.

Keywords: Biogenesis of lysosome-related organelle complex 1 (BLOC-1); Cryo-electron microscopy; Galactocerebroside; Lipid nanotube; Membrane model; Membrane-bound protein; OSBP; VAP-A.