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Dynamin self-assembles into rings suggesting a mechanism for coated vesicle budding
1Department of Cell Biology, Scripps Research Institute, La Jolla, California 92037.
Nature
|March 9, 1995
Summary
Dynamin, a GTPase, is essential for endocytosis. This study shows dynamin self-assembles into rings, constricting and pinching off coated vesicles during endocytosis.
Area of Science:
- Cell Biology
- Molecular Biology
Background:
- Dynamin is a GTPase superfamily member and mammalian homologue of Drosophila shibire.
- Mutations in shibire and dominant-negative dynamin mutants cause accumulation of coated pits, indicating dynamin's role in endocytosis and coated vesicle budding.
Purpose of the Study:
- To investigate the mechanism by which dynamin mediates coated vesicle budding.
- To determine if dynamin acts as a molecular switch or a mechanochemical enzyme in endocytosis.
Main Methods:
- Observation of dynamin self-assembly into rings and interconnected stacks.
- Comparison of dynamin ring dimensions with 'collars' observed at constricted coated pits.
Main Results:
- Dynamin spontaneously self-assembles into ring-like structures.
- These structures are comparable in size to the 'collars' found at the necks of invaginated coated pits.
Conclusions:
- Dynamin likely functions as a mechanochemical enzyme, assembling into rings around coated pit necks to constrict them.
- This ring assembly and subsequent conformational change are proposed to drive the pinching off of coated vesicles during endocytosis.