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Dynamic remodeling of the dynamin helix during membrane constriction
Adai Colom1,2, Lorena Redondo-Morata3, Nicolas Chiaruttini1
1Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland.
Summary
Dynamin, a protein essential for cell membrane fission, constricts membrane tubules through GTP-induced helix rearrangements. High-speed atomic force microscopy visualized these dynamic protein movements during the fission process.
Area of Science:
- Cell biology
- Biophysics
- Molecular motors
Background:
- Dynamin is a GTPase protein crucial for endocytosis and membrane fission.
- The mechanism by which dynamin constricts membrane tubules remains poorly understood.
Purpose of the Study:
- To visualize and understand the constriction mechanism of dynamin-coated membrane tubules during membrane fission.
- To investigate the role of GTP hydrolysis in dynamin helix dynamics.
Main Methods:
- High-speed atomic force microscopy (HS-AFM) was used for direct imaging of single dynamin-coated membrane tubules.
- Analysis focused on dynamic rearrangements of dynamin helix turns in response to GTP.
Main Results:
- GTP hydrolysis induces dynamic rearrangements in dynamin helix turns, reducing inter-turn distances.
- Helical turns exhibit transient pairing and dissociation, correlating with constriction.
- Relative longitudinal and lateral displacements of helical turns are linked to membrane constriction.
Conclusions:
- Dynamin helix constriction involves dynamic rearrangements, including transient associations and dissociations of helical turns.
- HS-AFM provides high-resolution insights into the mechanochemical action of proteins on membranes.
- These findings elucidate a key step in the membrane fission process mediated by dynamin.
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