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Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
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Published on: March 9, 2012

Transformation by Rous sarcoma virus: effects of src gene expression on the synthesis and phosphorylation of cellular

K Radke, G S Martin

    Proceedings of the National Academy of Sciences of the United States of America
    |October 1, 1979
    PubMed

    Insights

    Rous sarcoma virus infection alters cellular protein synthesis and phosphorylation. A specific 36,000 Mr phosphoprotein emerges early in viral transformation, potentially targeted by pp60src kinase.

    Area of Science:

    • Cell Biology
    • Virology
    • Molecular Biology

    Background:

    • Rous sarcoma virus (RSV) infection causes significant changes in chicken embryo fibroblast growth and morphology.
    • Understanding the molecular mechanisms of viral transformation is crucial for cancer research.

    Purpose of the Study:

    • To investigate the effects of RSV infection on cellular polypeptide synthesis and phosphorylation.
    • To identify specific protein alterations associated with viral transformation.

    Main Methods:

    • Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was employed to analyze protein synthesis and phosphorylation patterns.
    • [35S]methionine and [32P]orthophosphate labeling were used to track newly synthesized and phosphorylated proteins, respectively.
    • Experiments utilized a temperature-sensitive mutant of RSV to study early transformation events.

    Main Results:

    • RSV infection did not induce significant de novo synthesis or complete suppression of major cellular polypeptides.
    • Quantitative changes were observed in a small fraction (approx. 4%) of [35S]methionine-labeled polypeptides.
    • A 36,000 Mr phosphoprotein was detected in RSV-transformed cells, appearing rapidly upon temperature shift in cells infected with a temperature-sensitive mutant.

    Conclusions:

    • Viral transformation by RSV leads to subtle quantitative changes in protein synthesis but significant alterations in protein phosphorylation.
    • The early appearance of the 36,000 Mr phosphoprotein suggests its role as an early event in transformation.
    • This phosphoprotein is a potential target for the kinase activity of pp60src, a key viral oncoprotein.

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