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Force generation by cytoskeletal filament end-tracking proteins.
Richard B Dickinson1, Luzelena Caro, Daniel L Purich
1Department of Chemical Engineering, University of Florida Colleges of Engineering and Medicine, Gainesville, Florida 32611-6005, USA. dickinso@che.ufl.edu
Biophysical Journal
|September 30, 2004
Summary
Processive filament end-tracking motors, powered by nucleoside triphosphate (NTP) hydrolysis, generate significant force for cell motility by tethered filaments. These motors outperform passive trackers and free filament elongation.
Area of Science:
- Cell Biology
- Biophysics
- Molecular Motors
Background:
- Cell motility relies on cytoskeletal filaments tethered to objects.
- Existing models struggle to explain force generation by tethered, elongating filaments.
- Filament end-tracking proteins are crucial for directed cell movement.
Purpose of the Study:
- To explain force generation by persistently tethered, elongating cytoskeletal filaments.
- To introduce the concept of filament end-tracking motors.
- To analyze the advantages of end-tracking motors over other elongation mechanisms.
Main Methods:
- Analysis of kinetic and thermodynamic properties of end-tracking mechanisms.
- Energy inventory of filament treadmilling.
- Modeling of end-tracking stepping and direct-transfer motors.
Main Results:
- Processive end-tracking motors facilitate rapid elongation and substantial force generation.
- NTP hydrolysis provides more energy than needed for steady-state filament assembly.
- End-tracking motors offer advantages in force generation, monomer addition, and filament end possession.
Conclusions:
- Filament end-tracking motors are key to efficient cell motility.
- NTP hydrolysis is essential for the high performance of these motors.
- Cofactors like profilin and EB1 likely play roles in motor function.