1
|
D’Ippolito R, Rabara D, Blanco MA, Alberico E, Drew MR, Ramakrishnan N, Sontan D, Widmeyer SRT, Scheidemantle GM, Messing S, Turner D, Arkin M, Maciag AE, Stephen AG, Esposito D, McCormick F, Nissley DV, DeHart CJ. A Top-Down Proteomic Assay to Evaluate KRAS4B-Compound Engagement. Anal Chem 2024; 96:5223-5231. [PMID: 38498381 PMCID: PMC10993199 DOI: 10.1021/acs.analchem.3c05626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024]
Abstract
Development of new targeted inhibitors for oncogenic KRAS mutants may benefit from insight into how a given mutation influences the accessibility of protein residues and how compounds interact with mutant or wild-type KRAS proteins. Targeted proteomic analysis, a key validation step in the KRAS inhibitor development process, typically involves both intact mass- and peptide-based methods to confirm compound localization or quantify binding. However, these methods may not always provide a clear picture of the compound binding affinity for KRAS, how specific the compound is to the target KRAS residue, and how experimental conditions may impact these factors. To address this, we have developed a novel top-down proteomic assay to evaluate in vitro KRAS4B-compound engagement while assessing relative quantitation in parallel. We present two applications to demonstrate the capabilities of our assay: maleimide-biotin labeling of a KRAS4BG12D cysteine mutant panel and treatment of three KRAS4B proteins (WT, G12C, and G13C) with small molecule compounds. Our results show the time- or concentration-dependence of KRAS4B-compound engagement in context of the intact protein molecule while directly mapping the compound binding site.
Collapse
Affiliation(s)
- Robert
A. D’Ippolito
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Dana Rabara
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Maria Abreu Blanco
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Emily Alberico
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Matthew R. Drew
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Nitya Ramakrishnan
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Dara Sontan
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Stephanie R. T. Widmeyer
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Grace M. Scheidemantle
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Simon Messing
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - David Turner
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Michelle Arkin
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, California 94143, United States
- Small
Molecule Discovery Center, University of
California, San Francisco, California 94143, United States
| | - Anna E. Maciag
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Andrew G. Stephen
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Dominic Esposito
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Frank McCormick
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
- Helen
Diller Family Comprehensive Cancer Center, University of California, San
Francisco, California 94158, United States
| | - Dwight V. Nissley
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Caroline J. DeHart
- NCI
RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| |
Collapse
|
2
|
Abstract
Lysine acetyltransferases (KATs) play a critical role in the regulation of transcription and other genomic functions. However, a persistent challenge is the development of assays capable of defining KAT activity directly in living cells. Toward this goal, here we report the application of a previously reported dCas9-p300 fusion as a transcriptional reporter of KAT activity. First, we benchmark the activity of dCas9-p300 relative to other dCas9-based transcriptional activators and demonstrate its compatibility with second generation short guide RNA architectures. Next, we repurpose this technology to rapidly identify small molecule inhibitors of acetylation-dependent gene expression. These studies validate a recently reported p300 inhibitor chemotype and reveal a role for p300s bromodomain in dCas9-p300-mediated transcriptional activation. Comparison with other CRISPR-Cas9 transcriptional activators highlights the inherent ligand tunable nature of dCas9-p300 fusions, suggesting new opportunities for orthogonal gene expression control. Overall, our studies highlight dCas9-p300 as a powerful tool for studying gene expression mechanisms in which acetylation plays a causal role and provide a foundation for future applications requiring spatiotemporal control over acetylation at specific genomic loci.
Collapse
Affiliation(s)
- Jonathan H Shrimp
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
| | - Carissa Grose
- Protein Expression Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc. , Frederick, Maryland 21702, United States
| | - Stephanie R T Widmeyer
- Protein Expression Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc. , Frederick, Maryland 21702, United States
| | - Abigail L Thorpe
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
| | - Ajit Jadhav
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health , Rockville, Maryland 20850, United States
| | - Jordan L Meier
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
| |
Collapse
|