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Depolymerization of brain microtubules by skeletal muscle myosin
Journal of Biochemistry
|March 1, 1979
Abstract:
Brain microtubules are found to disperse rods of skeletal muscle myosin and become decorated with amorphous aggregates of myosin. Then microtubules are partially depolymerized by myosin. Myosin shows high Mg2+-GTPase activity which is not influenced by microtubules, and induces the partial depolymerization of microtubules by exhaustion of GTP in the solution. H-meromyosin depolymerizes microtubules like myosin does. H-meromyosin is, however, contaminated with a trace amount of trypsin, which irreversibly depolymerizes microtubules.
Insights
Brain microtubules interact with skeletal muscle myosin, causing aggregation and partial depolymerization. Myosin
Area of Science:
- Cell Biology
- Biochemistry
- Cytoskeleton Dynamics
Background:
- Microtubules are essential cytoskeletal components involved in various cellular processes.
- Skeletal muscle myosin is a motor protein responsible for muscle contraction.
- The interaction between microtubules and myosin is crucial for cellular structure and function.
Purpose of the Study:
- To investigate the interaction between brain microtubules and skeletal muscle myosin.
- To elucidate the mechanism by which myosin affects microtubule stability.
- To determine the role of myosin's enzymatic activity in microtubule depolymerization.
Main Methods:
- Purification of brain microtubules and skeletal muscle myosin.
- Observation of microtubule-myosin interactions using electron microscopy.
- Assay of myosin Mg2+-GTPase activity in the presence and absence of microtubules.
- Analysis of microtubule depolymerization kinetics.
Main Results:
- Myosin disperses microtubule structures and forms aggregates on them.
- Myosin induces partial depolymerization of microtubules.
- Myosin exhibits high Mg2+-GTPase activity, independent of microtubules.
- GTP exhaustion by myosin leads to microtubule depolymerization.
- H-meromyosin also depolymerizes microtubules, with trypsin contamination causing irreversible depolymerization.
Conclusions:
- Skeletal muscle myosin interacts with and destabilizes brain microtubules.
- Myosin's GTPase activity, leading to GTP depletion, is a key factor in microtubule depolymerization.
- Trypsin contamination in H-meromyosin contributes to irreversible microtubule depolymerization.