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Regulation of p21ras activity

D R Lowy1, K Zhang, J E DeClue

  • 1Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD 20892.

Trends in Genetics : TIG
|November 1, 1991
PubMed

Insights

Ras genes produce GTP/GDP-binding proteins crucial for cell signaling. Their activity, regulated by GTP-p21ras levels, involves positive and negative control mechanisms like GAP and NF1, influencing mitogenic signals.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Oncogenes

Background:

  • Ras genes encode GTP/GDP-binding proteins essential for signal transduction.
  • These proteins mediate mitogenic signals from membrane tyrosine kinases to cellular targets.
  • The activity of p21ras is regulated by the concentration of its GTP-bound form.

Purpose of the Study:

  • To elucidate the regulatory mechanisms controlling p21ras activity.
  • To identify factors involved in the positive and negative regulation of ras signaling pathways.

Main Methods:

  • Analysis of ras gene function in cellular signaling pathways.
  • Investigation of protein-protein interactions involving ras proteins.
  • Biochemical assays to measure GTP/GDP binding and hydrolysis rates.

Main Results:

  • p21ras activity is tightly controlled by GTP-p21ras concentration.
  • GTPase-activating protein (GAP) and Neurofibromin 1 (NF1) negatively regulate p21ras by promoting GTP hydrolysis.
  • Other cellular factors positively regulate p21ras by facilitating GDP/GTP exchange.

Conclusions:

  • Ras signaling is modulated by a complex interplay of positive and negative regulators.
  • GAP and NF1 are key negative regulators of ras activity.
  • Understanding these regulatory mechanisms is vital for comprehending cell growth and disease states.

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