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Proton ionophores prevent assembly of a peroxisomal protein

E Bellion, J M Goodman

    Cell
    |January 16, 1987
    PubMed

    Insights

    Proton ionophores disrupt the assembly of alcohol oxidase, a peroxisomal protein, by preventing octamerization and causing dissociation of existing octamers. This suggests energy is crucial for peroxisomal protein import and maturation.

    Area of Science:

    • Cell Biology
    • Biochemistry
    • Yeast Genetics

    Background:

    • Peroxisomal matrix proteins are imported post-translationally.
    • Alcohol oxidase is a homo-octameric flavoprotein found in the induced peroxisome of the methylotrophic yeast Candida boidinii.

    Purpose of the Study:

    • To investigate the role of proton gradients in the import and assembly of peroxisomal proteins.
    • To elucidate the assembly pathway of alcohol oxidase in Candida boidinii.

    Main Methods:

    • Treatment of Candida boidinii cells with proton ionophores.
    • Analysis of alcohol oxidase assembly and dissociation using biochemical assays.
    • Microscopy to observe protein localization and complex formation.

    Main Results:

    • Proton ionophores disrupt alcohol oxidase import and assembly.
    • Newly synthesized monomers fail to octamerize and form a membrane-associated complex.
    • Existing octamers dissociate into monomers upon drug addition.
    • Complex formation is reversible upon drug removal, leading to octamer generation.

    Conclusions:

    • Proton ionophores interfere with alcohol oxidase maturation.
    • A membrane-associated complex and labile octamers are likely intermediates in alcohol oxidase assembly.
    • Cellular energy is required for the import and maturation of peroxisomal proteins like alcohol oxidase.

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