PQBP1 promotes translational elongation and regulates hippocampal mGluR-LTD by suppressing eEF2 phosphorylation

Mol Cell. 2021 Apr 1;81(7):1425-1438.e10. doi: 10.1016/j.molcel.2021.01.032. Epub 2021 Mar 3.

Abstract

Eukaryotic elongation factor 2 (eEF2) mediates translocation of peptidyl-tRNA from the ribosomal A site to the P site to promote translational elongation. Its phosphorylation on Thr56 by its single known kinase eEF2K inactivates it and inhibits translational elongation. Extensive studies have revealed that different signal cascades modulate eEF2K activity, but whether additional factors regulate phosphorylation of eEF2 remains unclear. Here, we find that the X chromosome-linked intellectual disability protein polyglutamine-binding protein 1 (PQBP1) specifically binds to non-phosphorylated eEF2 and suppresses eEF2K-mediated phosphorylation at Thr56. Loss of PQBP1 significantly reduces general protein synthesis by suppressing translational elongation. Moreover, we show that PQBP1 regulates hippocampal metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) and mGluR-LTD-associated behaviors by suppressing eEF2K-mediated phosphorylation. Our results identify PQBP1 as a novel regulator in translational elongation and mGluR-LTD, and this newly revealed regulator in the eEF2K/eEF2 pathway is also an excellent therapeutic target for various disease conditions, such as neural diseases, virus infection, and cancer.

Keywords: PQBP1; Renpenning syndrome; eEF2; mGluR-LTD; novel object recognition; phosphorylation; protein synthesis; spatial recognition; translational elongation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • HEK293 Cells
  • HeLa Cells
  • Hippocampus / metabolism*
  • Humans
  • Long-Term Synaptic Depression*
  • Mice
  • Mice, Knockout
  • Peptide Chain Elongation, Translational*
  • Peptide Elongation Factor 2 / genetics
  • Peptide Elongation Factor 2 / metabolism*
  • Phosphorylation
  • Receptors, Metabotropic Glutamate / biosynthesis*
  • Receptors, Metabotropic Glutamate / genetics

Substances

  • DNA-Binding Proteins
  • PQBP1 protein, human
  • Peptide Elongation Factor 2
  • Pqbp1 protein, mouse
  • Receptors, Metabotropic Glutamate