Reversible lysine-targeted probes reveal residence time-based kinase selectivity

Area of Science:

• Medicinal Chemistry
• Chemical Biology
• Drug Discovery

Background:

• Covalent inhibitors typically target cysteine residues, limiting their application.
• Engaging the catalytic lysine in protein kinases presents a challenge for selective covalent inhibition.
• Few lysine-targeting covalent inhibitors have demonstrated efficacy in vivo.

Purpose of the Study:

• To develop novel covalent inhibitors targeting protein kinase catalytic lysines.
• To explore reversible covalent engagement for sustained in vivo kinase inhibition.
• To achieve selectivity through differences in inhibitor residence time.

Main Methods:

• Design and synthesis of benzaldehyde-linked kinase inhibitors.
• Utilizing chemoproteomic probes to identify targeted kinases in cells and mice.
• Employing X-ray crystallography to elucidate structural basis of inhibitor-kinase interactions.

Main Results:

• Developed probes that reversibly and covalently engage over 200 protein kinases.
• Demonstrated enhanced probe-kinase residence time with ortho-hydroxyl substitution.
• Identified specific kinases, like Aurora A, with sustained in vivo occupancy.

Conclusions:

• Salicylaldehyde-based probes enable reversible covalent targeting of protein kinases via lysine.
• This approach broadens the scope of covalent inhibition to targets lacking druggable cysteines.
• The findings support the potential for sustained kinase engagement in vivo.