The RNA-Binding Protein KSRP Promotes Decay of β-Catenin mRNA and Is Inactivated by PI3K-AKT Signaling
2007

KSRP and β-Catenin mRNA Decay

publication Evidence: high

Author Information

Author(s): Gherzi Roberto, Trabucchi Michele, Ponassi Marco, Ruggiero Tina, Corte Giorgio, Moroni Christoph, Chen Ching-Yi, Khabar Khalid S, Andersen Jens S, Briata Paola

Primary Institution: Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy

Hypothesis

KSRP is required for the decay of β-catenin mRNA and is inactivated by PI3K-AKT signaling.

Conclusion

The study reveals that KSRP is crucial for the rapid degradation of β-catenin mRNA, and its phosphorylation by AKT signaling impairs this function.

Supporting Evidence

  • β-catenin mRNA is labile and its half-life is prolonged by Wnt and PI3K-AKT signaling.
  • KSRP is a major determinant of β-catenin mRNA instability.
  • AKT phosphorylates KSRP, impairing its ability to promote mRNA decay.
  • Insulin-induced AKT activation stabilizes β-catenin mRNA.
  • KSRP knockdown leads to increased β-catenin mRNA levels.
  • Phosphorylated KSRP interacts with 14-3-3, affecting its decay-promoting activity.
  • AKT activation impairs KSRP's interaction with the exosome.

Takeaway

KSRP helps break down a specific type of RNA that controls cell growth, and when a certain signal is turned on, it stops working, allowing the RNA to stick around longer.

Methodology

The study used RT-PCR and microarray analysis to assess mRNA stability and decay rates in response to various treatments.

Digital Object Identifier (DOI)

10.1371/journal.pbio.0050005

Want to read the original?

Access the complete publication on the publisher's website

View Original Publication