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Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Phosphorylation of the eukaryotic initiation factor 3f by cyclin-dependent kinase 11 during apoptosis

Jiaqi Shi1, John W B Hershey, Mark A Nelson

  • 1Department of Surgery, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA. sjq@email.arizona.edu

FEBS Letters
|February 28, 2009
PubMed

Insights

Cyclin-dependent kinase 11 (CDK11) phosphorylates eukaryotic initiation factor 3f (eIF3f) at a new site during apoptosis. This phosphorylation regulates translation and enhances eIF3f binding to the eIF3 complex.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Eukaryotic initiation factor 3 subunit f (eIF3f) is a key component of the translation initiation complex.
  • Cyclin-dependent kinase 11 (CDK11) is implicated as an effector in apoptotic pathways.
  • Previous work established CDK11(p46) as a kinase for eIF3f.

Purpose of the Study:

  • To identify novel phosphorylation sites on eIF3f by CDK11(p46) during apoptosis.
  • To elucidate the functional consequences of eIF3f phosphorylation on translation and apoptosis.

Main Methods:

  • In vivo phosphorylation analysis.
  • Identification of phosphorylation sites using mass spectrometry.
  • Co-immunoprecipitation assays to assess protein-protein interactions.

Main Results:

  • A second CDK11(p46) phosphorylation site on eIF3f, Thr119, was identified during apoptosis.
  • eIF3f is directly phosphorylated by CDK11(p46) in vivo.
  • Phosphorylation of eIF3f enhances its association with core eIF3 subunits.
  • This enhanced binding suggests eIF3f may inhibit translation during apoptosis.

Conclusions:

  • CDK11(p46) phosphorylation of eIF3f at Thr119 is a critical regulatory event during apoptosis.
  • Phosphorylation modulates eIF3f function in both translation and apoptosis.
  • eIF3f's interaction with the eIF3 complex is strengthened upon phosphorylation, potentially leading to translational repression.

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