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Updated: Aug 10, 2026
Identification of Kinase-substrate Pairs Using High Throughput Screening
Published on: August 29, 2015
Isolation of novel substrates using a tyrosine kinase overlay/in situ assay
1Department of Medicine, Division of Infectious Diseases and Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, NY, USA.
Abstract:
Identifying substrates of receptor and non-receptor protein tyrosine kinases (PTK), and how phosphorylation of these substrates affects signaling and cytoskeletal pathways, has been a key step in understanding the role of PTK in differentiation, mitogenesis and oncogenesis. However, it has been difficult to distinguish substrates phosphorylated directly by PTK vs those phosphorylated by PTK-activated kinases. The following describes an in situ/overlay technique in which purified PTK (in our case, FAK) can be used to identify potential substrates from filter lifts of protein produced from a cDNA expression library.
Insights
This study introduces a new method to identify direct protein tyrosine kinase (PTK) substrates. This technique helps distinguish PTK-phosphorylated proteins from those altered by downstream kinases, advancing PTK research.
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Protein tyrosine kinases (PTKs) are crucial in cell differentiation, proliferation, and cancer.
- Distinguishing direct PTK substrates from those phosphorylated by PTK-activated kinases is challenging.
- Understanding PTK substrate interactions is vital for deciphering signaling and cytoskeletal pathway regulation.
Purpose of the Study:
- To develop and describe an in situ/overlay technique for identifying direct PTK substrates.
- To enable the differentiation between proteins directly phosphorylated by PTKs and those phosphorylated by secondary kinases.
- To facilitate the study of focal adhesion kinase (FAK) substrates.
Main Methods:
- An in situ/overlay assay was developed using purified PTK (specifically FAK).
- The technique involves applying purified PTK to filter lifts of proteins expressed from a cDNA library.
- This method allows for the direct identification of potential PTK substrates.
Main Results:
- The described technique successfully identifies potential direct substrates of PTKs.
- It provides a means to differentiate direct PTK targets from indirect phosphorylation events.
- The method is demonstrated using purified focal adhesion kinase (FAK).
Conclusions:
- The developed in situ/overlay technique is effective for identifying direct PTK substrates.
- This method overcomes the challenge of distinguishing direct vs. indirect phosphorylation.
- It offers a valuable tool for investigating PTK roles in cellular processes like differentiation and oncogenesis.
