PIM-induced phosphorylation of Notch3 promotes breast cancer tumorigenicity in a CSL-independent fashion.

Autor:	Landor SKJ; Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland., Santio NM; Department of Biology, University of Turku, Turku, Finland., Eccleshall WB; Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland; Department of Biology, University of Turku, Turku, Finland., Paramonov VM; Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland; Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Turku, Finland., Gagliani EK; Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Ohio, USA., Hall D; Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Ohio, USA., Jin SB; Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden., Dahlström KM; Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi, Turku, Finland., Salminen TA; Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi, Turku, Finland., Rivero-Müller A; Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland; Department of Biology, University of Turku, Turku, Finland., Lendahl U; Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden., Kovall RA; Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Ohio, USA., Koskinen PJ; Department of Biology, University of Turku, Turku, Finland. Electronic address: paivi.koskinen@utu.fi., Sahlgren C; Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland; Department of Biomedical Engineering, Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands. Electronic address: csahlgre@abo.fi.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2021 Jan-Jun; Vol. 296, pp. 100593. Date of Electronic Publication: 2021 Mar 26.
DOI:	10.1016/j.jbc.2021.100593
Abstrakt:	Dysregulation of the developmentally important Notch signaling pathway is implicated in several types of cancer, including breast cancer. However, the specific roles and regulation of the four different Notch receptors have remained elusive. We have previously reported that the oncogenic PIM kinases phosphorylate Notch1 and Notch3. Phosphorylation of Notch1 within the second nuclear localization sequence of its intracellular domain (ICD) enhances its transcriptional activity and tumorigenicity. In this study, we analyzed Notch3 phosphorylation and its functional impact. Unexpectedly, we observed that the PIM target sites are not conserved between Notch1 and Notch3. Notch3 ICD (N3ICD) is phosphorylated within a domain, which is essential for formation of a transcriptionally active complex with the DNA-binding protein CSL. Through molecular modeling, X-ray crystallography, and isothermal titration calorimetry, we demonstrate that phosphorylation of N3ICD sterically hinders its interaction with CSL and thereby inhibits its CSL-dependent transcriptional activity. Surprisingly however, phosphorylated N3ICD still maintains tumorigenic potential in breast cancer cells under estrogenic conditions, which support PIM expression. Taken together, our data indicate that PIM kinases modulate the signaling output of different Notch paralogs by targeting distinct protein domains and thereby promote breast cancer tumorigenesis via both CSL-dependent and CSL-independent mechanisms. Competing Interests: Conflict of interest U. L. holds research grants from Merck KGaA, no personal remuneration. All other authors declare that they have no conflicts of interest with the contents of this article. (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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