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Updated: Aug 15, 2026

Adenofection: A Method for Studying the Role of Molecular Chaperones in Cellular Morphodynamics by Depletion-Rescue Experiments
12:34

Adenofection: A Method for Studying the Role of Molecular Chaperones in Cellular Morphodynamics by Depletion-Rescue Experiments

Published on: September 16, 2016

Modulation of adenylate cyclase by guanine nucleotides and Kirsten sarcoma virus mediated transformation

D Saltarelli, S Fischer, G Gacon

    Biochemical and Biophysical Research Communications
    |February 28, 1985
    PubMed

    Insights

    Activated ras genes in tumor cells produce p21 proteins. Researchers found that p21 protein levels correlate with changes in adenylate cyclase activity, suggesting a role in cell signaling.

    Area of Science:

    • Molecular Biology
    • Cellular Biology
    • Oncology

    Background:

    • Activated ras genes in tumor cells encode 21,000-dalton proteins (p21).
    • These p21 proteins bind guanine nucleotides and associate with the inner plasma membrane.
    • The function of p21 proteins in relation to other GTP-binding proteins requires investigation.

    Purpose of the Study:

    • To investigate the regulation of adenylate cyclase (AC) activity by guanine nucleotides in fibroblasts expressing temperature-sensitive ras.
    • To determine if p21 protein expression influences AC activity.
    • To correlate alterations in the AC system with ras gene expression.

    Main Methods:

    • Utilized membrane preparations from C127 fibroblasts transformed with a temperature-sensitive Kirsten sarcoma virus mutant (Ts 371).
    • Assessed adenylate cyclase (AC) activity in response to guanine nucleotides (GMP P(NH)P) at different temperatures (33°C vs. 39°C).
    • Compared results with rat fibroblasts infected with Rous Sarcoma virus and C127 cells infected with wild-type KiMSV.

    Main Results:

    • Increased AC stimulation by GMP P(NH)P was observed when cells were shifted to the non-permissive temperature (39°C), indicating a link to p21 expression.
    • This effect was more pronounced at lower Mg++ and GMP P(NH)P concentrations.
    • AC stimulation remained unchanged in Rous Sarcoma virus-infected cells, while it was depressed in wild-type KiMSV-infected cells.

    Conclusions:

    • Demonstrated the feasibility of correlating changes in the adenylate cyclase system with ras gene expression.
    • Provided experimental evidence supporting the investigation of p21 protein physiological functions.
    • Highlighted the potential of using AC activity as a marker for ras gene activity in cellular processes.

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