1. Photoaffinity Labeling and Quantitative Chemical Proteomics Identify LXRβ as the Functional Target of Enhancers of Astrocytic apoE
- Author
-
Christopher W. am Ende, Ethan Lawrence Fisher, Erica C. Dresselhaus, Leah Cleary, John M. Humphrey, Edelweiss Evrard, Douglas S. Johnson, Patrick Robert Verhoest, Jamison B. Tuttle, Travis T. Wager, Longfei Xie, Emily Sylvain, Zhen Huang, Martin Pettersson, Uthpala Seneviratne, Lorraine F. Lanyon, Michael Marconi, Claire M. Steppan, Gayathri Ramaswamy, Simone Sciabola, Christopher John Helal, Michael Eric Green, Butler Todd W, and Paramita Mukherjee
- Subjects
Proteomics ,Thermal shift assay ,Phenotypic screening ,Clinical Biochemistry ,Peptide ,Biology ,Ligands ,01 natural sciences ,Biochemistry ,Article ,Cell Line ,chemistry.chemical_compound ,Apolipoproteins E ,Drug Discovery ,Humans ,Enhancer ,Liver X receptor ,Molecular Biology ,Liver X Receptors ,Pharmacology ,chemistry.chemical_classification ,Photoaffinity labeling ,010405 organic chemistry ,0104 chemical sciences ,chemistry ,Astrocytes ,Molecular Medicine ,Lead compound ,Protein Binding - Abstract
Summary Utilizing a phenotypic screen, we identified chemical matter that increased astrocytic apoE secretion in vitro. We designed a clickable photoaffinity probe based on a pyrrolidine lead compound and carried out probe-based quantitative chemical proteomics in human astrocytoma CCF-STTG1 cells to identify liver x receptor β (LXRβ) as the target. Binding of the small molecule ligand stabilized LXRβ, as shown by cellular thermal shift assay (CETSA). In addition, we identified a probe-modified peptide by mass spectrometry and proposed a model where the photoaffinity probe is bound in the ligand-binding pocket of LXRβ. Taken together, our findings demonstrated that the lead chemical matter bound directly to LXRβ, and our results highlight the power of chemical proteomic approaches to identify the target of a phenotypic screening hit. Additionally, the LXR photoaffinity probe and lead compound described herein may serve as valuable tools to further evaluate the LXR pathway.
- Published
- 2021