RagD auto-activating mutations impair MiT/TFE activity in kidney tubulopathy and cardiomyopathy syndrome


Heterozygous mutations in the gene encoding RagD GTPase were shown to cause a novel autosomal dominant condition characterized by kidney tubulopathy and cardiomyopathy. We previously demonstrated that RagD, and its paralogue RagC, mediate a non-canonical mTORC1 signaling pathway that inhibits the activity of TFEB and TFE3, transcription factors of the MiT/TFE family and master regulators of lysosomal biogenesis and autophagy. Here we show that RagD mutations causing kidney tubulopathy and cardiomyopathy are "auto- activating", even in the absence of Folliculin, the GAP responsible for RagC/D activation, and cause constitutive phosphorylation of TFEB and TFE3 by mTORC1, without affecting the phosphorylation of "canonical" mTORC1 substrates, such as S6K. By using HeLa and HK-2 cell lines, human induced pluripotent stem cell-derived cardiomyocytes and patient-derived primary fibroblasts, we show that RRAGD auto-activating mutations lead to inhibition of TFEB and TFE3 nuclear translocation and transcriptional activity, which impairs the response to lysosomal and mitochondrial injury. These data suggest that inhibition of MiT/TFE factors plays a key role in kidney tubulopathy and cardiomyopathy syndrome. © 2023. The Author(s).

Authors Sambri I, Ferniani M, Campostrini G, Testa M, Meraviglia V, de Araujo MEG, Dokládal L, Vilardo C, Monfregola J, Zampelli N, Vecchio Blanco FD, Torella A, Ruosi C, Fecarotta S, Parenti G, Staiano L, Bellin M, Huber LA, De Virgilio C, Trepiccione F, Nigro V, Ballabio A
Journal Nature communications
Publication Date 2023 May 15;14(1):2775
PubMed 37188688
PubMed Central PMC10185561
DOI 10.1038/s41467-023-38428-2

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