RuPHOTACs Provide Photocontrol Over Protein Degradation with Optimized Properties for Biological Applications

Area of Science:

• Chemical Biology
• Molecular Biology
• Drug Discovery

Background:

• PROteolysis TArgeting Chimeras (PROTACs) induce protein degradation but lack spatiotemporal control, leading to off-target effects.
• Developing methods for precise control over PROTAC activity is crucial for therapeutic applications and chemical biology research.

Purpose of the Study:

• To develop light-activated PROTACs (RuPHOTACs) for spatiotemporal control of protein degradation.
• To validate RuPHOTACs targeting epigenetic regulators like bromodomain proteins, c-MYC, and PIM1.
• To implement a novel reporter system for accurate monitoring of protein degradation rates in live cells.

Main Methods:

• Synthesis and characterization of Ruthenium-based PHOToActivated Chimeras (RuPHOTACs).
• Validation of RuPHOTACs activity against target proteins using low-energy red light.
• Development of a Dendra2 fusion protein reporter system for live-cell analysis of protein degradation.

Main Results:

• RuPHOTACs demonstrated high selectivity for light-induced activation and improved potency.
• Effective degradation of bromodomain proteins, c-MYC, and PIM1 in vitro and in vivo.
• The Dendra2 reporter system accurately measured protein degradation rates, decoupling degradation from synthesis.

Conclusions:

• Ruthenium-based photocages enable precise light-triggered PROTAC activity, enhancing spatiotemporal control.
• RuPHOTACs offer advantages in selectivity, potency, and in vivo efficacy compared to traditional PROTACs.
• The novel reporter system provides a superior method for assessing PROTAC-mediated protein degradation in live cells.