Visualizing membrane trafficking through the electron microscope: cryo-tomography of coat complexes

Area of Science:

• Cell Biology
• Structural Biology
• Biochemistry

Background:

• Coat proteins are crucial for vesicular transport, enabling molecule distribution within eukaryotic cells.
• The arrangement of coat proteins on membranes dictates their function in intracellular trafficking.
• Understanding coat protein structure is vital for deciphering cellular organization and function.

Purpose of the Study:

• To present a comprehensive workflow for the structural elucidation of membrane-bound coat proteins.
• To highlight recent advancements in cryo-electron tomography (cryo-ET) data acquisition and processing for coat protein studies.
• To review current knowledge on coat protein I (COPI), coat protein II (COPII), and retromer complexes.

Main Methods:

• Cryo-electron tomography (cryo-ET) for high-resolution imaging of membrane-associated protein complexes.
• Subtomogram averaging to determine the 3D structure of coat proteins.
• In vitro reconstitution and in situ studies to investigate coat protein mechanisms.

Main Results:

• Recent cryo-ET studies provide crucial structural insights into coat protein organization on membranes.
• Summarized research addresses fundamental questions about membrane binding, polymerization, and assembly regulation of COPI, COPII, and retromer.
• The review integrates new data processing techniques with established structural biology methods.

Conclusions:

• The described workflow facilitates detailed structural analysis of coat proteins.
• Advances in cryo-ET have significantly enhanced our understanding of coat protein function and regulation.
• This review consolidates key findings, advancing the study of vesicular transport mechanisms.