Related Experiment Videos
Multiple ATP-hydrolyzing sites that potentially function in cytoplasmic dynein
Yoshinori Takahashi1, Masaki Edamatsu, Yoko Y Toyoshima
1Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Summary
Cytoplasmic dynein utilizes multiple ATP-binding sites for hydrolysis, with AAA modules requiring adjacent sites for activity. This research clarifies the complex ATPase function of this essential cellular motor.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Cytoplasmic dynein is a crucial minus-end-directed microtubule motor protein essential for eukaryotic cell functions like nuclear segregation and intracellular transport.
- The dynein motor domain contains six AAA (ATPase associated with diverse cellular activities) modules (AAA1-AAA6), with the first four possessing nucleotide-binding sites (P-loops) that bind ATP.
Purpose of the Study:
- To investigate the specific roles and functions of the multiple ATP-binding sites within cytoplasmic dynein.
- To identify which P-loops are responsible for ATP hydrolysis, a challenging aspect due to measurement difficulties.
Main Methods:
- Purification of truncated Saccharomyces cerevisiae cytoplasmic dynein fragments and their mutants expressed in E. coli.
- Measurement of ATPase activities of these purified dynein fragments and mutants.
Main Results:
- Results indicate that cytoplasmic dynein possesses multiple ATP-binding sites capable of ATP hydrolysis.
- A single AAA module alone is insufficient for ATP hydrolysis; the adjacent module is necessary for this activity.
Conclusions:
- Cytoplasmic dynein's ATPase activity is complex, involving multiple interacting AAA modules.
- Understanding these interactions is key to elucidating the motor's mechanism and function in cellular processes.