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In Vitro Analysis of E3 Ubiquitin Ligase Function
06:06

In Vitro Analysis of E3 Ubiquitin Ligase Function

Published on: May 14, 2021

The E3 ligase TTC3 facilitates ubiquitination and degradation of phosphorylated Akt

Futoshi Suizu1, Yosuke Hiramuki, Fumihiko Okumura

  • 1Division of Cancer Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.

Developmental Cell
|January 12, 2010
PubMed

Insights

Tetratricopeptide repeat domain 3 (TTC3) acts as an E3 ligase, targeting the survival factor Akt for degradation. This interaction, elevated in Down syndrome (DS) cells, may contribute to DS symptoms.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • The serine/threonine kinase Akt is a crucial survival factor implicated in numerous human diseases.
  • While phosphorylation regulates Akt, other post-translational modifications influencing its activity are not well understood.

Purpose of the Study:

  • To investigate novel post-translational mechanisms modulating Akt activity.
  • To identify and characterize the function of tetratricopeptide repeat domain 3 (TTC3) in relation to Akt.

Main Methods:

  • Protein interaction studies to confirm TTC3 and Akt binding.
  • Ubiquitination assays to assess Akt modification by TTC3.
  • Cellular studies using siRNA and Akt activators in Down syndrome (DS) cell models.

Main Results:

  • Tetratricopeptide repeat domain 3 (TTC3) identified as an Akt-specific E3 ligase.
  • TTC3 binds to phosphorylated Akt, promoting its ubiquitination and nuclear degradation.
  • DS cells show increased TTC3, decreased phosphorylated Akt, and G2M cell cycle arrest, reversible by TTC3 inhibition or Akt activation.

Conclusions:

  • TTC3-mediated Akt degradation is a novel regulatory pathway.
  • The interaction between TTC3 and Akt may play a role in the pathophysiology of Down syndrome.

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