A light-resuming strategy as a screening method for selecting Sec61 inhibitors down-modulating PD-L1 expression.

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Sec61 translocon inhibitors offer a promising strategy for treating cancers and viral infections.
• A sensitive and direct screening platform for identifying Sec61 inhibitors is currently lacking.

Purpose of the Study:

• To develop a novel, sensitive, and direct screening assay for Sec61 inhibitors.
• To identify small molecules that interfere with protein translocation into the endoplasmic reticulum (ER).

Main Methods:

• Development of the "resuming luminescence upon translocation interference" (RELITE) assay.
• Utilizing firefly luciferase translocation into the ER and its subsequent diversion to the cytosol by Sec61 inhibitors.
• Screening for small molecules that inhibit PD-L1 protein expression by interfering with ER translocation.

Main Results:

• Successfully developed the RELITE assay for single-round screening of Sec61 inhibitors.
• Identified small molecules that impede PD-L1 protein expression by disrupting ER translocation.
• Demonstrated the assay's capability to select inhibitors that promote degradation of target proteins.

Conclusions:

• The RELITE assay provides a powerful tool for selecting Sec61 inhibitors.
• This method facilitates the identification of compounds for down-modulating disease-relevant protein expression.
• The developed assay will accelerate the discovery of novel therapeutics for various pathologies.