Speaker: Fabio P. Gomes, Virginia Commonwealth University

Topic: Native Top-Down Characterization of Proteins and their Complexes in Breast Cancer Cells

Date: April 15, 2024

Time: 6:15 pm Dinner, 7:15 pm Presentation

Location: Shimadzu Scientific Instrument, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Jonathan Ferguson (jonathan.ferguson33@gmail.com) by Friday, April 12 if you will be attending the dinner.

Abstract: Oligomerization of proteins and their modified forms (proteoforms) produces functional protein complexes. Complexoforms are complexes that consist of the same set of proteins with different proteoforms. The ability to characterize these assemblies within cells is critical to understanding the molecular mechanisms involved in disease and to designing effective drugs. An outstanding biological question is how proteoforms drive function and oligomerization of complexoforms. However, tools to define endogenous proteoform-proteoform/ligand interactions are scarce. I will present a native top-down proteomics (nTDP) strategy that combines size-exclusion chromatography, nano direct infusion, field asymmetric ion mobility spectrometry, and multistage mass spectrometry to identify protein assemblies (≤70 kDa) in breast cancer cells and in cells that overexpress EGFR, which serves as a resistance model of estrogen receptor-α (ER-α) targeted therapies. This nTDP approach was able to identify ~104 complexoforms from 17 protein complexes, which revealed several molecular features of the breast cancer proteome, including EGFR-induced dissociation of nuclear transport factor 2 (NUTF2) assemblies that modulate ER activity. We found that the K4 and K55 posttranslational modification sites discovered with nTDP differentially impact the effects of NUTF2 on the inhibition of the ER signaling pathway.
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