A novel quantitative kinase assay using bacterial surface display and flow cytometry

PLoS One. 2013 Nov 15;8(11):e80474. doi: 10.1371/journal.pone.0080474. eCollection 2013.

Abstract

The inhibition of tyrosine kinases is a successful approach for the treatment of cancers and the discovery of kinase inhibitor drugs is the focus of numerous academic and pharmaceutical laboratories. With this goal in mind, several strategies have been developed to measure kinase activity and to screen novel tyrosine kinase inhibitors. Nevertheless, a general non-radioactive and inexpensive approach, easy to implement and adapt to a range of applications, is still missing. Herein, using Bcr-Abl tyrosine kinase, an oncogenic target and a model protein for cancer studies, we describe a novel cost-effective high-throughput screening kinase assay. In this approach, named the BacKin assay, substrates displayed on a Bacterial cell surface are incubated with Kinase and their phosphorylation is examined and quantified by flow cytometry. This approach has several advantages over existing approaches, as using bacteria (i.e. Escherichia coli) to display peptide substrates provides a self renewing solid support that does not require laborious chemical strategies. Here we show that the BacKin approach can be used for kinetic and mechanistic studies, as well as a platform to characterize and identify small-molecule or peptide-based kinase inhibitors with potential applications in drug development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / metabolism*
  • Cell Surface Display Techniques*
  • Enzyme Activation
  • Enzyme Assays / methods*
  • Flow Cytometry*
  • Fusion Proteins, bcr-abl / antagonists & inhibitors
  • Fusion Proteins, bcr-abl / chemistry
  • Fusion Proteins, bcr-abl / metabolism
  • Kinetics
  • Models, Molecular
  • Peptide Fragments / chemistry
  • Peptide Fragments / metabolism
  • Phosphotransferases / antagonists & inhibitors
  • Phosphotransferases / chemistry
  • Phosphotransferases / metabolism*
  • Protein Binding
  • Protein Conformation
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacology
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / chemistry
  • Protein-Tyrosine Kinases / metabolism
  • Reproducibility of Results
  • Substrate Specificity

Substances

  • Peptide Fragments
  • Protein Kinase Inhibitors
  • Phosphotransferases
  • Protein-Tyrosine Kinases
  • Fusion Proteins, bcr-abl

Grants and funding

This research was supported by an UQ Early Career Research Grant to STH. STH is the recipient of a Discovery Early Career Researcher Award [DE120103152], awarded by the Australian Research Council. DJC is a National Health and Medical Research Council Professorial Fellow [APP1026501]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.