Pseudokinase-converting mutation in protein kinase C alpha drives chordoid glioma by pathway rewiring
Abstract
Chordoid glioma (ChG) is a rare, low-grade brain tumor characterized by a novel recurrent point mutation, D463H, in the kinase domain of protein kinase C alpha (PKCα). The mutation is invariably an Asp to His substitution, suggesting a unique function beyond catalytic inactivation associated with other cancer-associated PKCα mutations. Here, we show that this mutation converts PKCα into a pseudokinase, abolishing catalytic activity, and, additionally, confers novel scaffolding functions. Activity assays in vitro and in cellulo revealed that PKCα D463H is catalytically inactive and functions as a dominant-negative to suppress endogenous PKC activity. Molecular dynamics simulations predicted that mutation to His, but not Asn, not only destabilizes the active site, but stabilizes the substrate-binding helices in the kinase C-lobe to potentially promote aberrant interactions. Supporting this, phosphoproteomic, proximity labeling, and coimmunoprecipitation mass spectrometry data from cells overexpressing PKCα D463H identified both altered phosphorylation of substrates and binding to multiple proteins involved in cell–cell junctions compared to WT enzyme. Last, single nuclei RNAseq established that ChG derives from specialized tanycytes. Our data reveal that this disease-defining, fully penetrant mutation converts PKCα into a pseudokinase with novel scaffold functions that uniquely rewire the cellular interactome to impair cell junction function.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (21)
Charlotte Bellamy
Institut du Cerveau, Paris Brain Institute (ICM, CNRS, Inria, Inserm), équipe labellisée Ligue Nationale contre le Cancer, Hôpital de la Pitié Salpêtrière, Sorbonne Université
Hannah Tovell
Tiffany H. Kao
Alexandr Kornev
LSP Consulting LLC
Quentin Letourneur
Assistance Publique - Hôpitaux de Paris, Sorbonne Université, Site de Recherche Intégrée sur le Cancer Curamus
Janan Arslan
Institut du Cerveau, Paris Brain Institute (ICM, CNRS, Inria, Inserm), équipe labellisée Ligue Nationale contre le Cancer, Hôpital de la Pitié Salpêtrière, Sorbonne Université
Selina Schwaighofer
Institute of Molecular Biology and Center for Molecular Biosciences (CMBI), University of Innsbruck
Timothy R. Baffi
Department of Pharmacology, University of California, San Diego
Florent Dingli
CurieCoreTech Mass Spectrometry Proteomics, Institut Curie, Paris Sciences Lettres (PSL) Research University
Damarys Loew
Julie Lerond
Institut du Cerveau, Paris Brain Institute (ICM, CNRS, Inria, Inserm), équipe labellisée Ligue Nationale contre le Cancer, Hôpital de la Pitié Salpêtrière, Sorbonne Université
Stephane Liva
Inserm, U900, Institute Curie
Brigitte Izac
CNRS, INSERM, Institut Cochin, Université Paris Cité
Muriel Andrieu
Université Paris Cité, CNRS UMR 8104, Inserm U1016
Homa Adle-Biassette
Assistance Publique - Hôpitaux de Paris, Hôpital Lariboisière, Department of Pathology
Jean-Vianney Barnier
CNRS, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay
Eduard Stefan
Institute of Molecular Biology and Center for Molecular Biosciences (CMBI), University of Innsbruck
Susan S. Taylor
Marc Sanson
Alexandra C. Newton
Franck Bielle