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Cryo-electron tomography of clathrin-coated vesicles: structural implications for coat assembly
Yifan Cheng1, Werner Boll, Tomas Kirchhausen
1Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA. ycheng@biochem.ucsf.edu
Journal of Molecular Biology
|November 11, 2006
Summary
Clathrin-coated vesicles exhibit diverse lattice structures and enclose offset vesicles. This structural variability provides insights into vesicle formation and membrane interactions during cellular transport.
Area of Science:
- Cell Biology
- Structural Biology
- Biophysics
Background:
- Clathrin-coated vesicles are crucial for intracellular vesicular transport.
- Previous studies used averaged reconstructions, limiting analysis of individual vesicle heterogeneity.
- Understanding clathrin coat structure and vesicle interaction is key to cellular trafficking.
Purpose of the Study:
- To investigate the structural diversity of individual clathrin-coated vesicles using cryo-electron tomography.
- To analyze the organization of the clathrin lattice and its relationship with the enclosed vesicle.
- To explore the molecular basis of clathrin-vesicle interactions.
Main Methods:
- Cryo-electron tomography (cryo-ET) was employed to image individual clathrin-coated vesicles.
- 3D reconstructions were generated to analyze lattice patterns and vesicle positioning.
- Electron density distribution and coat-vesicle contacts were quantified.
Main Results:
- A wide range of clathrin lattice designs, including various facet patterns (pentagonal, hexagonal, heptagonal), were observed.
- Enclosed membrane vesicles were frequently found to be offset within the clathrin shell.
- The electron density between the coat and vesicle was non-uniform, with fewer apparent contacts than clathrin heavy chains.
Conclusions:
- The diverse clathrin lattice structures reflect intrinsic assembly properties.
- The eccentric vesicle position suggests a polarity in coat assembly and membrane scission.
- These findings advance our understanding of the structural dynamics of clathrin-mediated endocytosis.
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