Characterization of Ligand Binding to Pseudokinases Using a Thermal Shift Assay

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Pseudokinases are critical regulators of signal transduction pathways and emerging drug targets.
• Their regulatory functions rely on protein-protein interactions, unlike traditional kinases.
• Understanding ligand-induced conformational changes is key to their biological function.

Purpose of the Study:

• To describe a robust method for measuring pseudokinase-ligand interactions.
• To assess the druggability of pseudokinase nucleotide-binding sites.
• To optimize buffer conditions for protein stability.

Main Methods:

• Utilized a fluorescence-based thermal shift assay (TSA).
• Employed SYPRO Orange dye to detect protein unfolding via fluorescence changes.
• Measured shifts in thermal denaturation curves upon ligand binding.

Main Results:

• Successfully measured pseudokinase-ligand interactions for multiple pseudokinases (ErbB3/HER3, ILK, ROP5Bi, JAK1, JAK2, TYK2, MLKL, STRAD, TRIB1, VRK3, ROR1).
• Demonstrated the assay's ability to indicate ligand-induced increases in protein thermal stability.
• Validated the method for optimizing buffer conditions and protein stability.

Conclusions:

• The described TSA protocol is a reliable method for pseudokinase-ligand interaction studies.
• This assay aids in understanding pseudokinase mechanisms and identifying potential drug candidates.
• The method is adaptable for other protein families and stability optimization.