Michael R Lazear, Jarrett R Remsberg, Martin G Jaeger, Katherine Rothamel, Hsuan-Lin Her, Kristen E DeMeester, Evert Njomen, Simon J Hogg, Jahan Rahman, Landon R Whitby, Sang Joon Won, Michael A Schafroth, Daisuke Ogasawara, Minoru Yokoyama, Garrett L Lindsey, Haoxin Li, Jason Germain, Sabrina Barbas, Joan Vaughan, Thomas W Hanigan, Vincent F Vartabedian, Christopher J Reinhardt, Melissa M Dix, Seong Joo Koo, Inha Heo, John R Teijaro, Gabriel M Simon, Brahma Ghosh, Omar Abdel-Wahab, Kay Ahn, Alan Saghatelian, Bruno Melillo, Stuart L Schreiber, Gene W Yeo, Benjamin F Cravatt
Most human proteins lack chemical probes, and several large-scale and generalizable small-molecule binding assays have been introduced to address this problem. How compounds discovered in such "binding-first" assays affect protein function, nonetheless, often remains unclear. Here, we describe a "function-first" proteomic strategy that uses size exclusion chromatography (SEC) to assess the global impact of electrophilic compounds on protein complexes in human cells. Integrating the SEC data with cysteine-directed activity-based protein profiling identifies changes in protein-protein interactions that are caused by site-specific liganding events, including the stereoselective engagement of cysteines in PSME1 and SF3B1 that disrupt the PA28 proteasome regulatory complex and stabilize a dynamic state of the spliceosome, respectively...
April 18, 2023: Molecular Cell