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Updated: Oct 1, 2026

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

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

Published on: March 9, 2012

Participation of small GTPases Rac1 and Cdc42Hs in myoblast transformation

Mayya Meriane1, Sophie Charrasse, Franck Comunale

  • 1Centre de Recherche de Biochimie Macromoléculaire (CRBM), CNRS UPR 1086, 1919 Route de Mende, 34293 Montpellier Cedex, France.

Oncogene
|April 26, 2002
PubMed

Insights

Active Rac1 and Cdc42Hs small GTPases impair skeletal muscle cell differentiation and promote tumor growth. Constitutive activation of these proteins was found in rhabdomyosarcoma, suggesting their role in muscle tumor development.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Oncology

Background:

  • Previous studies indicated that active Rac1 and Cdc42Hs inhibit skeletal muscle cell differentiation.
  • The role of RhoA in these processes was less clear.

Purpose of the Study:

  • To investigate the role of Rac1, Cdc42Hs, and RhoA in skeletal muscle cell cycle exit and tumor formation.
  • To determine if Rac1 and Cdc42Hs are constitutively activated in rhabdomyosarcoma.

Main Methods:

  • L6 myoblast cell culture and differentiation.
  • Bromodeoxyuridine incorporation and cyclin D1 expression analysis.
  • Focus forming activity and soft agar growth assays.
  • Analysis of human rhabdomyosarcoma cell lines.
  • Use of dominant-negative forms of Rac1 and Cdc42Hs.

Main Results:

  • Active Rac1 and Cdc42Hs, but not RhoA, impaired L6 myoblast cell cycle exit.
  • Expression of active Rac1 and Cdc42Hs led to loss of contact inhibition and anchorage-dependent growth.
  • Constitutive activation of Rac1 and Cdc42Hs was observed in human rhabdomyosarcoma cell lines.
  • Dominant-negative Rac1 and Cdc42Hs inhibited RD rhabdomyosarcoma cell proliferation.

Conclusions:

  • Rac1 and Cdc42Hs play a significant role in inhibiting skeletal muscle cell differentiation and promoting cell proliferation.
  • Constitutive activation of Rac1 and Cdc42Hs is implicated in the pathogenesis of skeletal muscle tumors, specifically rhabdomyosarcoma.

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