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Microtubule assembly using the microtubule-associated protein MAP-2 prepared in defined states of phosphorylation

A S Murthy, M Flavin

    European Journal of Biochemistry
    |December 1, 1983
    PubMed

    Insights

    Phosphorylation of microtubule-associated protein 2 (MAP-2) by kinases decreases microtubule assembly rates and increases subunit loss. Dephosphorylation by phosphatases reverses these effects, highlighting phosphorylation

    Area of Science:

    • Cell Biology
    • Neuroscience
    • Biochemistry

    Background:

    • Microtubule-associated protein 2 (MAP-2) is crucial for microtubule dynamics.
    • The role of MAP-2 phosphorylation in regulating microtubule assembly is not fully understood.

    Purpose of the Study:

    • To investigate the impact of MAP-2 phosphorylation on microtubule assembly and stability.
    • To characterize the effects of specific phosphorylation states on MAP-2 binding to microtubules.

    Main Methods:

    • Preparation of MAP-2 in defined phosphorylation states using kinase and phosphatase treatments.
    • Assembly of microtubules with phosphorylated and dephosphorylated MAP-2.
    • Analysis of microtubule assembly kinetics, subunit loss rates, and MAP-2 binding to taxol-stabilized microtubules.

    Main Results:

    • Phosphorylation of MAP-2 (24 mol/mol) decreased microtubule assembly rate and increased subunit loss from both ends.
    • Microtubule length and critical concentration remained unaffected by MAP-2 phosphorylation.
    • Phosphorylation reduced MAP-2 binding to taxol-stabilized microtubules, an effect reversed by phosphatase treatment.

    Conclusions:

    • MAP-2 phosphorylation significantly alters microtubule dynamics, primarily by affecting assembly and disassembly rates.
    • The findings suggest a regulatory role for MAP-2 phosphorylation in neuronal development and function.
    • Further research is needed to identify brain-specific phosphatases that regulate MAP-2 activity.

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