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Role of T198 modification in the regulation of p27(Kip1) protein stability and function

Monica Schiappacassi1, Sara Lovisa, Francesca Lovat

  • 1Division of Experimental Oncology 2, Centro di Riferimento Oncologico, National Cancer Institute, Aviano, Italy.

Plos One
|March 23, 2011
PubMed

Insights

The tumor suppressor p27 (Kip1) protein

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Oncology

Background:

  • The tumor suppressor p27 (Kip1) is crucial in cancer progression.
  • p27's tumor suppression involves inhibiting Cyclin/CDK complexes and modulating cell motility.
  • The C-terminal portion and specifically Threonine 198 (T198) are key to p27's functions.

Purpose of the Study:

  • To investigate the role of Threonine 198 (T198) in p27 (Kip1) protein stability and cell motility.
  • To elucidate the mechanisms by which T198 influences p27's regulatory functions.

Main Methods:

  • Analysis of T198 modifications and their impact on p27 protein stability.
  • Investigation of T198 phosphorylation's role in cell motility regulation.
  • Assessment of p27's interaction with Cyclin/CDK complexes and Skp2.
  • Examination of proteasome-dependent degradation pathways.

Main Results:

  • Threonine 198 (T198) is essential for regulating p27 (Kip1) protein stability and cell motility.
  • T198 phosphorylation controls cell motility, while its steric hindrance regulates protein stability.
  • p27 stability is not affected by binding to Cyclin/CDK complexes or Skp2.
  • Conformational changes in p27's C-terminal region influence proteasome degradation.
  • T198 phosphorylation promotes p27/stathmin interaction, impacting cell motility.

Conclusions:

  • Threonine 198 (T198) is a critical regulatory site for p27 (Kip1) function.
  • Protein stability and cell motility are differentially regulated by T198's presence and phosphorylation.
  • These findings offer insights into p27's role in cancer and potential therapeutic strategies.

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