1. AMBRA1 links autophagy to cell proliferation and tumorigenesis by promoting c-Myc dephosphorylation and degradation
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Cecconi, Francesco, Cianfanelli, Valentina, Fuoco, Claudia, Lorente Pérez, María Del Mar, Salazar Roa, María, Quondamatteo, Fabio, Gherardini, Pier Federico, De Zio, Daniela, Nazio, Francesca, Antonioli, Manuela, D’Orazio, Melania, Skobo, Tatjana, Bordi, Matteo, Rohde, Mikkel, Dalla Valle, Luisa, Helmer-Citterich, Manuela, Gretzmeier, Christine, Dengjel, Joern, Fimia, Gian Maria, Piacentini, Mauro, Di Bartolomeo, Sabrina, Velasco Díez, Guillermo, Cecconi, Francesco, Cianfanelli, Valentina, Fuoco, Claudia, Lorente Pérez, María Del Mar, Salazar Roa, María, Quondamatteo, Fabio, Gherardini, Pier Federico, De Zio, Daniela, Nazio, Francesca, Antonioli, Manuela, D’Orazio, Melania, Skobo, Tatjana, Bordi, Matteo, Rohde, Mikkel, Dalla Valle, Luisa, Helmer-Citterich, Manuela, Gretzmeier, Christine, Dengjel, Joern, Fimia, Gian Maria, Piacentini, Mauro, Di Bartolomeo, Sabrina, and Velasco Díez, Guillermo
- Abstract
Acknowledgements We wish to thank M. Canney, V. Unterkircher, R. Laricchia and M. Salomé for excellent technical assistance, and M. Acuña Villa and M. W. Bennett for editorial and secretarial work. We also thank S. Campello for critical reading of the manuscript. We are indebted to R. Sears (Portland, Oregon, USA), A. C. Gingras (Toronto, Canada) and A. Teleman and K. Dimitriadis (Heidelberg, Germany) for providing us with V5–Flag–c-Myc and Flag–PR65A constructs and Tsc2 MEFs, respectively, and to S. Cannata (Rome) for his advice on histopathology. This work was supported by grants from KBVU (R72-A4408), Lundbeck Foundation (R167-2013-16100), Novo Nordisk Foundation (7559), The Bjarne Saxhof Foundation, AIRC (IG2010 and IG2012 to both F.C. and M.P.), and in part from FISM (2009), the Telethon Foundation (GGP10225), the Italian Ministry of University and Research (PRIN 2009 and FIRB Accordi di Programma 2011) and the Italian Ministry of Health (RF 2009). V.C. is supported by the Lundbeck Foundation (R165-2013-15982). Also, we are grateful to the Spanish Ministry of Economy and Competitiveness (MINECO) (PS09/01401; PI12/02248, FR2009-0052 and IT2009-0053) and to Fundación Mutua Madrileña (AP101042012) for funding the laboratory of G.V., Inhibition of a main regulator of cell metabolism, the protein kinase mTOR, induces autophagy and inhibits cell proliferation. However, the molecular pathways involved in the cross-talk between these two mTOR-dependent cell processes are largely unknown. Here we show that the scaffold protein AMBRA1, a member of the autophagy signalling network and a downstream target of mTOR, regulates cell proliferation by facilitating the dephosphorylation and degradation of the proto-oncogene c-Myc. We found that AMBRA1 favours the interaction between c-Myc and its phosphatase PP2A and that, when mTOR is inhibited, it enhances PP2A activity on this specific target, thereby reducing the cell division rate. As expected, such a de-regulation of c-Myc correlates with increased tumorigenesis in AMBRA1-defective systems, thus supporting a role for AMBRA1 as a haploinsufficient tumour suppressor gene., Depto. de Bioquímica y Biología Molecular, Fac. de Ciencias Biológicas, TRUE, pub
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- 2024
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