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Dynamin2 and cortactin regulate actin assembly and filament organization.
Dorothy A Schafer1, Scott A Weed, Derk Binns
1Department of Biology, University of Virginia, Charlottesville, VA 22904, USA. das9w@virginia.edu
Current Biology : CB
|November 7, 2002
Summary
Dynamin 2 (a GTPase) and cortactin regulate actin assembly at cell membranes. This interaction influences actin dynamics and filament organization, crucial for cellular processes.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Dynamin (a GTPase) is essential for endocytic vesicle formation.
- Dynamin's role in regulating the actin cytoskeleton is known but mechanistically unclear.
- Dynamin interacts with actin-binding proteins via its proline-rich domain (PRD).
Purpose of the Study:
- To investigate the interaction between dynamin 2 and cortactin in regulating actin assembly.
- To elucidate the mechanism by which dynamin 2 influences actin dynamics and organization at membranes.
Main Methods:
- Utilized cell-based assays with dynamin 2 and cortactin mutants in cultured cells.
- Performed in vitro experiments with purified Arp2/3 complex, cortactin, and dynamin 2.
- Investigated the association of actin filaments with lipid vesicles.
Main Results:
- Dynamin 2 mutants with reduced GTP binding decreased actin dynamics in cells.
- Cortactin mutants with impaired Arp2/3 or dynamin 2 binding also reduced actin dynamics.
- Dynamin 2 exhibited biphasic regulation of Arp2/3-cortactin-mediated actin nucleation in vitro.
- Dynamin 2 promoted actin filament association with PIP2-containing vesicles, with GTP hydrolysis affecting organization.
Conclusions:
- Dynamin 2, via interaction with cortactin, regulates actin assembly and filament organization at membranes.
- This mechanism is important for cellular processes involving actin dynamics at the plasma membrane.