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

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Tyrosine kinase inhibition is a validated strategy for cancer treatment.
• Developing novel kinase inhibitors requires efficient screening assays.
• Existing assays often lack cost-effectiveness, simplicity, or broad applicability.

Purpose of the Study:

• To develop a novel, cost-effective, high-throughput screening assay for kinase activity.
• To establish a general, non-radioactive method adaptable for various applications.
• To utilize Bcr-Abl tyrosine kinase as a model for assay development and validation.

Main Methods:

• The Bacterial Kinase (BacKin) assay employs peptide substrates displayed on the surface of *Escherichia coli*.
• Kinase activity is measured by quantifying substrate phosphorylation.
• Flow cytometry is used for examining and quantifying phosphorylation events.

Main Results:

• The BacKin assay provides a cost-effective and high-throughput method for kinase screening.
• Bacteria serve as a self-renewing solid support, eliminating complex chemical strategies.
• The assay is suitable for kinetic studies, mechanistic investigations, and inhibitor characterization.

Conclusions:

• The BacKin assay is a versatile and advantageous platform for identifying small-molecule and peptide-based kinase inhibitors.
• This approach facilitates cancer drug development by offering a simplified and economical screening tool.
• The method demonstrates potential for broad application in kinase research and pharmaceutical laboratories.