Maite Baz-Martínez, Emilio Lecona, Mariano Esteban, Ahmed El Motiam, Yanis Hichem Bouzaher, Anxo Vidal, Manuel S. Rodriguez, Carlos F. de la Cruz-Herrera, Carmen Rivas, Rocío Seoane, Manuel Collado, Santiago Vidal, Ministerio de Ciencia, Innovación y Universidades (España), Xunta de Galicia, CIMUS Biomedical Research Institute [Santiago de Compostela], Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), University of Toronto, Universidad Autonoma de Madrid (UAM), Centro Nacional de Biotecnología [Madrid] (CNB-CSIC), Biocomputing Unit [Madrid], Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ministry of Science, Innovation and Universities, FEDER (BFU-2017-88880-P), Xunta de Galicia (ED431G2019/02), Universidade de Santiago de Compostela [Spain] (USC ), Instituto de Investigación Sanitaria de Santiago de Compostela / Health Research Institute of Santiago de Compostela (IDIS), Universidad Autónoma de Madrid (UAM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
Class I PI3K are heterodimers composed of a p85 regulatory subunit and a p110 catalytic subunit involved in multiple cellular functions. Recently, the catalytic subunit p110β has emerged as a class I PI3K isoform playing a major role in tumorigenesis. Understanding its regulation is crucial for the control of the PI3K pathway in p110β-driven cancers. Here we sought to evaluate the putative regulation of p110β by SUMO. Our data show that p110β can be modified by SUMO1 and SUMO2 in vitro, in transfected cells and under completely endogenous conditions, supporting the physiological relevance of p110β SUMOylation. We identify lysine residue 952, located at the activation loop of p110β, as essential for SUMOylation. SUMOylation of p110β stabilizes the protein increasing its activation of AKT which promotes cell growth and oncogenic transformation. Finally, we show that the regulatory subunit p85β counteracts the conjugation of SUMO to p110β. In summary, our data reveal that SUMO is a novel p110β interacting partner with a positive effect on the activation of the PI3K pathway., Funding at the laboratory of CR is provided by Ministry of Science, Innovation and Universities and FEDER (BFU-2017–88,880-P) and Xunta de Galicia (ED431G 2019/02). SV and RS are predoctoral fellows funded by Xunta de Galicia-Consellería de Cultura, Educación y Ordenación Universitaria (ED481A-2018/110 and ED481A-2020/160, respectively)