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Updated: Jul 24, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
10:27

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Raf-1 protein kinase is required for growth of induced NIH/3T3 cells

W Kolch1, G Heidecker, P Lloyd

  • 1Laboratory of Viral Carcinogenesis, NIH/NCI, Frederick Cancer Research and Development Center, Maryland 21702-1201.

Nature
|January 31, 1991
PubMed

Insights

Raf-1 kinase is essential for cell growth signaling. Inhibiting Raf-1 function blocks proliferation and transformation, confirming its role downstream of growth factor receptors and ras oncogenes.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Oncogenesis

Background:

  • Raf-1 protein kinase is a key regulator of growth factor-mediated signal transduction.
  • Its ubiquitous expression and role in proliferation suggest importance in receptor signaling pathways.

Purpose of the Study:

  • To determine if Raf-1 kinase is essential for serum- and TPA-regulated NIH/3T3 cell growth.
  • To investigate the role of Raf-1 in signal transduction downstream of growth factor receptors and oncogenes.

Main Methods:

  • Inhibition of Raf-1 function using c-raf-1 antisense RNA.
  • Expression of kinase-defective c-raf-1 mutants (craf301) and regulatory domain fragments (HCR).
  • Assessment of NIH/3T3 cell proliferation and DNA replication induced by serum or TPA.

Main Results:

  • Antisense RNA against c-raf-1 interfered with NIH/3T3 cell proliferation and reverted raf-transformed cells.
  • Inhibition of Raf-1 function, via antisense RNA or kinase-defective mutants, blocked proliferation and transformation induced by serum, TPA, and ras oncogenes.
  • Reduced Raf protein levels correlated with reduced DNA replication.

Conclusions:

  • Raf-1 kinase functions as an essential signal transducer in pathways initiated by serum growth factor receptors, protein kinase C, and ras.
  • Raf-1 is critical for mediating cellular responses to growth signals and oncogenic transformation.

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