A dynamic mechanism for allosteric activation of Aurora kinase A by activation loop phosphorylation

Elife. 2018 Feb 21;7:e32766. doi: 10.7554/eLife.32766.

Abstract

Many eukaryotic protein kinases are activated by phosphorylation on a specific conserved residue in the regulatory activation loop, a post-translational modification thought to stabilize the active DFG-In state of the catalytic domain. Here we use a battery of spectroscopic methods that track different catalytic elements of the kinase domain to show that the ~100 fold activation of the mitotic kinase Aurora A (AurA) by phosphorylation occurs without a population shift from the DFG-Out to the DFG-In state, and that the activation loop of the activated kinase remains highly dynamic. Instead, molecular dynamics simulations and electron paramagnetic resonance experiments show that phosphorylation triggers a switch within the DFG-In subpopulation from an autoinhibited DFG-In substate to an active DFG-In substate, leading to catalytic activation. This mechanism raises new questions about the functional role of the DFG-Out state in protein kinases.

Keywords: computational biology; human; molecular biophysics; phosphorylation; protein dynamics; protein kinase; structural biology; systems biology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation*
  • Aurora Kinase A / chemistry*
  • Aurora Kinase A / metabolism*
  • Electron Spin Resonance Spectroscopy
  • Enzyme Activation*
  • Molecular Dynamics Simulation
  • Phosphorylation
  • Protein Processing, Post-Translational*
  • Spectrum Analysis

Substances

  • AURKA protein, human
  • Aurora Kinase A