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Messenger RNA for a phorbol-ester induced 48,000 dalton protein from human melanoma cells

G Opdenakker, F Bosman, J Van Damme

    Biochemical and Biophysical Research Communications
    |April 14, 1986
    PubMed

    Insights

    Researchers isolated and characterized messenger RNA (mRNA) for a 48kDa protein in human melanoma cells. This protein is induced by phorbol ester and appears to be an intracellular, non-secreted polypeptide.

    Area of Science:

    • Molecular Biology
    • Cancer Research
    • Protein Biochemistry

    Background:

    • Phorbol esters are known to induce specific gene expression in various cell types.
    • Human melanoma cells provide a model system for studying cancer-related protein synthesis.
    • Simultaneous induction of 48kDa protein mRNA and tissue-type plasminogen activator suggests a coordinated cellular response.

    Purpose of the Study:

    • To isolate and characterize the messenger RNA (mRNA) encoding a 48kDa protein induced by phorbol ester in human melanoma cells.
    • To investigate the processing and nature of the 48kDa protein.
    • To determine if the protein is secreted or intracellular.

    Main Methods:

    • Isolation and characterization of 48kDa mRNA using phenol extraction and sucrose gradient sedimentation.
    • In vitro translation of mRNA using reticulocyte lysates.
    • Analysis of translation products via sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE).

    Main Results:

    • The 48kDa mRNA was successfully isolated and characterized, showing a sedimentation coefficient of 20S and possessing a poly(A)-tail.
    • In vitro translation consistently produced a 48kDa protein, regardless of microsomal membrane presence.
    • SDS-PAGE analysis revealed the protein to be a monomeric, one-chain polypeptide, with no detectable glycosylation or signal peptide cleavage.

    Conclusions:

    • The phorbol ester-induced 48kDa protein in human melanoma cells is synthesized as a non-secreted, intracellular protein.
    • The absence of signal peptide cleavage and glycosylation supports its intracellular localization.
    • Further research can explore the specific function of this intracellular protein in melanoma cells.

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