Coat assembly and membrane remodelling: understanding regulation of protein secretion

2026-07-22

Eukaryotic cells are organised in membrane-bound compartments, which have defined chemical identities and carry out specific essential functions. Exchange of material between these compartments is necessary to maintain cell functionality, and is achieved in a highly specific and regulated manner by vesicular transport. To mediate protein trafficking, coat complexes assemble on membranes and couple bilayer deformation with cargo capture into transport carriers. How coat assembly can deliver the flexibility necessary to accommodate a wide variety of cargo proteins, and how the process can be regulated, are outstanding questions in the field. This is exemplified by the COPII coat, which mediates export from the ER of about a third of newly synthesized proteins. COPII assembles into two concentric layers and can form transport carriers of a variety of shapes and sizes, including tubules and spherical vesicles. This is important for export of large cargoes and is a process targeted by cargo-specific regulatory factors. The aim of this project proposal is to shed light on the molecular interactions between coat components, and understand their role in determination of coat architecture and membrane shape. We will use a combination of structural and functional approaches to characterise COPII coat assembly, and its relationship with membranes in systems of increasing complexity, ranging from in vitro reconstitutions to cells. In particular, we will use cryo-electron tomography and subtomogram averaging to understand the architecture of the coat layers in these systems. These are fast-developing techniques that uniquely target complex structures while achieving high resolutions. With my lab at the forefront of current advances, we are perfectly placed to obtain a complete view of the COPII coat assembled on membranes. Our research will answer outstanding questions in the membrane trafficking field and open new perspectives to tackle ill-characterised regulation systems.

United Kingdom (UK)

2025-11-01