A missense mutation in human INSC causes peripheral neuropathy

EMBO Mol Med. 2024 May;16(5):1091-1114. doi: 10.1038/s44321-024-00062-w. Epub 2024 Apr 8.

Abstract

PAR3/INSC/LGN form an evolutionarily conserved complex required for asymmetric cell division in the developing brain, but its post-developmental function and disease relevance in the peripheral nervous system (PNS) remains unknown. We mapped a new locus for axonal Charcot-Marie-Tooth disease (CMT2) and identified a missense mutation c.209 T > G (p.Met70Arg) in the INSC gene. Modeling the INSCM70R variant in Drosophila, we showed that it caused proprioceptive defects in adult flies, leading to gait defects resembling those in CMT2 patients. Cellularly, PAR3/INSC/LGN dysfunction caused tubulin aggregation and necrotic neurodegeneration, with microtubule-stabilizing agents rescuing both morphological and functional defects of the INSCM70R mutation in the PNS. Our findings underscore the critical role of the PAR3/INSC/LGN machinery in the adult PNS and highlight a potential therapeutic target for INSC-associated CMT2.

Keywords: Inscuteable; Charcot–Marie–Tooth Neuropathy Type 2; Microtubule-Stabilizing Agents; Necrosis; Proprioception.

MeSH terms

  • Adaptor Proteins, Signal Transducing* / genetics
  • Adaptor Proteins, Signal Transducing* / metabolism
  • Animals
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Charcot-Marie-Tooth Disease* / genetics
  • Charcot-Marie-Tooth Disease* / pathology
  • Cytoskeletal Proteins* / genetics
  • Cytoskeletal Proteins* / metabolism
  • Disease Models, Animal
  • Drosophila / genetics
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Humans
  • Mutation, Missense*
  • Nuclear Proteins
  • Peripheral Nervous System Diseases / genetics
  • Peripheral Nervous System Diseases / pathology
  • Tubulin / genetics
  • Tubulin / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • MAD2L1BP protein, human
  • Nuclear Proteins
  • Tubulin
  • insc protein, Drosophila
  • INSC protein, human
  • Cytoskeletal Proteins
  • Drosophila Proteins