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Di Michele M, Stes E, Vandermarliere E, Arora R, Astorga-Wells J, Vandenbussche J, van Heerde E, Zubarev R, Bonnet P, Linders JTM, Jacoby E, Brehmer D, Martens L, Gevaert K. Limited Proteolysis Combined with Stable Isotope Labeling Reveals Conformational Changes in Protein (Pseudo)kinases upon Binding Small Molecules. J Proteome Res 2015; 14:4179-93. [PMID: 26293246 DOI: 10.1021/acs.jproteome.5b00282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Likely due to conformational rearrangements, small molecule inhibitors may stabilize the active conformation of protein kinases and paradoxically promote tumorigenesis. We combined limited proteolysis with stable isotope labeling MS to monitor protein conformational changes upon binding of small molecules. Applying this method to the human serine/threonine kinase B-Raf, frequently mutated in cancer, we found that binding of ATP or its nonhydrolyzable analogue AMP-PNP, but not ADP, stabilized the structure of both B-Raf(WT) and B-Raf(V600E). The ATP-competitive type I B-Raf inhibitor vemurafenib and the type II inhibitor sorafenib stabilized the kinase domain (KD) but had distinct effects on the Ras-binding domain. Stabilization of the B-Raf(WT) KD was confirmed by hydrogen/deuterium exchange MS and molecular dynamics simulations. Our results are further supported by cellular assays in which we assessed cell viability and phosphorylation profiles in cells expressing B-Raf(WT) or B-Raf(V600E) in response to vemurafenib or sorafenib. Our data indicate that an overall stabilization of the B-Raf structure by specific inhibitors activates MAPK signaling and increases cell survival, helping to explain clinical treatment failure. We also applied our method to monitor conformational changes upon nucleotide binding of the pseudokinase KSR1, which holds high potential for inhibition in human diseases.
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Affiliation(s)
- Michela Di Michele
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
| | - Elisabeth Stes
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
| | - Elien Vandermarliere
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
| | - Rohit Arora
- Institut de Chimie Organique et Analytique (ICOA), UMR 7311 CNRS-Université d'Orléans , Pôle de chimie, Rue de Chartres, 45100 Orléans, France
| | | | - Jonathan Vandenbussche
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
| | - Erika van Heerde
- Oncology Discovery, Janssen Research and Development, A Division of Janssen Pharmaceutica NV , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Roman Zubarev
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Scheelelaberatoriet Scheeles väg 2, SE-171 77 Stockholm, Sweden
| | - Pascal Bonnet
- Institut de Chimie Organique et Analytique (ICOA), UMR 7311 CNRS-Université d'Orléans , Pôle de chimie, Rue de Chartres, 45100 Orléans, France
| | - Joannes T M Linders
- Oncology Discovery, Janssen Research and Development, A Division of Janssen Pharmaceutica NV , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Edgar Jacoby
- Oncology Discovery, Janssen Research and Development, A Division of Janssen Pharmaceutica NV , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Dirk Brehmer
- Oncology Discovery, Janssen Research and Development, A Division of Janssen Pharmaceutica NV , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Lennart Martens
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
| | - Kris Gevaert
- Department of Medical Protein Research, VIB , A. Baertsoenkaai 3, 9000 Ghent, Belgium.,Department of Biochemistry, Ghent University , A. Baertsoenkaai 3, 9000 Ghent, Belgium
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