Nature Communications (May 2023)

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

  • Irene Sambri,
  • Marco Ferniani,
  • Giulia Campostrini,
  • Marialuisa Testa,
  • Viviana Meraviglia,
  • Mariana E. G. de Araujo,
  • Ladislav Dokládal,
  • Claudia Vilardo,
  • Jlenia Monfregola,
  • Nicolina Zampelli,
  • Francesca Del Vecchio Blanco,
  • Annalaura Torella,
  • Carolina Ruosi,
  • Simona Fecarotta,
  • Giancarlo Parenti,
  • Leopoldo Staiano,
  • Milena Bellin,
  • Lukas A. Huber,
  • Claudio De Virgilio,
  • Francesco Trepiccione,
  • Vincenzo Nigro,
  • Andrea Ballabio

DOI
https://doi.org/10.1038/s41467-023-38428-2
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 13

Abstract

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Abstract 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.