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Inhibition of RhoA-mediated SRF activation by p116Rip

Jacqueline Mulder1, Aafke Ariaens, Francis P G van Horck

  • 1Division of Cellular Biochemistry and Centre for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.

FEBS Letters
|October 26, 2005
PubMed

Insights

p116Rip protein inhibits RhoA-mediated transcription by disrupting the actomyosin cytoskeleton. This actin-binding protein

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • p116Rip is an actin-binding protein identified as a RhoA binding partner.
  • It interacts with myosin-II phosphatase regulatory subunit (MBS) and is crucial for Rho-regulated cytoskeletal contractility.

Purpose of the Study:

  • To investigate the role of p116Rip in RhoA-mediated activation of the transcription factor Serum Response Factor (SRF).
  • To elucidate the mechanism by which p116Rip influences RhoA signaling.

Main Methods:

  • Overexpression of wild-type and mutant p116Rip.
  • Assessment of RhoA-GTP levels.
  • Analysis of RhoA-induced SRF activation.
  • Investigation of p116Rip oligomerization and MBS binding.

Main Results:

  • p116Rip oligomerizes through its C-terminal coiled-coil domain.
  • Overexpressed p116Rip inhibits RhoA-induced SRF activation without altering RhoA-GTP levels.
  • Mutants of p116Rip unable to oligomerize or bind MBS retain inhibitory activity on SRF.

Conclusions:

  • p116Rip inhibits RhoA-mediated transcription.
  • The inhibitory mechanism involves the disassembly of the actomyosin cytoskeleton downstream of RhoA.
  • p116Rip's function in SRF regulation is independent of its direct interaction with MBS or its oligomerization status.

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