The PP2A-B55α phosphatase is a master regulator of mitochondrial degradation and biogenesis
Valentina Cianfanelli, Monica Nanni, Samantha Corrà, Sofia Mauri, David Sumpton, Sergio Lilla, Rossella De Cegli, Matteo Bordi, Giacomo Milletti, Caterina Ferraina, Arnaldur Hall, Michele Petraroia, Valentina Clausi, Ezio Giorda, Marco Scarsella, Alessandra Barbiera, Giulia Cadeddu, Marco Colasanti, Tiziana Persichini, Kenji Maeda, Apolinar Maya-Mendoza, Jiri Bartek, Chiara Di Malta, Franco Locatelli, Sara Zanivan, Shehab Ismail, Elena Ziviani, Francesco CecconiMitochondrial homeostasis relies on a tight balance between mitochondrial biogenesis and degradation. Although mitophagy is one of the main pathways involved in the clearance of damaged or old mitochondria, its coordination with mitochondrial biogenesis is poorly characterized. Here, by unbiased approaches including last-generation liquid chromatography coupled to mass spectrometry and transcriptomics, we identify the protein phosphatase PP2A-B55α/PPP2R2A as a Parkin-dependent regulator of mitochondrial number. Upon mitochondrial damage, PP2A-B55α determines the amplitude of mitophagy induction and execution by regulating both early and late mitophagy events. A few minutes after the insult, ULK1 is released from the inhibitory regulation of PP2A-B55α, whereas 2 to 4 hours later, PP2A-B55α promotes the nuclear translocation of TFEB, the master regulator of autophagy and lysosome genes, to support mitophagy execution. Moreover, PP2A-B55α controls a transcriptional program of mitochondrial biogenesis by stabilizing the Parkin substrate and PGC-1α inhibitor PARIS. PP2A-B55α targeting rescues neurodegenerative phenotypes in a fly model of Parkinson’s disease, thus suggesting potential therapeutic application.