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Phosphorylation affects the ability of tau protein to promote microtubule assembly
Abstract:
Tau is a family of closely related proteins known for its ability to copolymerize with tubulin, inducing the formation of microtubules. When tau was stripped of phosphate by treatment with alkaline phosphatase it underwent a pronounced change in electrophoretic mobility, probably reflecting a conformational change. The dephosphorylated tau promoted significantly more rapid and more extensive polymerization of microtubules though there was no obvious difference in the microtubules formed. Partially purified microtubule protein contains a kinase that can rephosphorylate tau.
Insights
Dephosphorylated tau (a protein) significantly enhances microtubule polymerization. This suggests that tau
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- Tau is a protein family that copolymerizes with tubulin.
- Tau facilitates microtubule formation.
- Microtubule assembly is crucial for cellular structure and function.
Purpose of the Study:
- To investigate the role of tau phosphorylation in microtubule polymerization.
- To determine the effect of dephosphorylated tau on microtubule formation.
- To identify kinases involved in tau phosphorylation within microtubule protein preparations.
Main Methods:
- Treatment of tau with alkaline phosphatase to remove phosphate groups.
- Electrophoretic analysis to assess conformational changes in tau.
- In vitro polymerization assays to measure microtubule formation.
- Analysis of partially purified microtubule protein for kinase activity.
Main Results:
- Dephosphorylated tau exhibited altered electrophoretic mobility, indicating a conformational change.
- Dephosphorylated tau significantly accelerated and increased the extent of microtubule polymerization.
- No discernible differences were observed in the structure of microtubules formed with native versus dephosphorylated tau.
- A kinase capable of rephosphorylating tau was detected in partially purified microtubule protein.
Conclusions:
- Tau phosphorylation state critically regulates its ability to promote microtubule polymerization.
- Dephosphorylation of tau enhances its interaction with tubulin, leading to more robust microtubule assembly.
- The presence of a tau kinase in microtubule preparations suggests an endogenous regulatory mechanism for tau function.