TMEM63C mutations cause mitochondrial morphology defects and underlie hereditary spastic paraplegia

Luis Carlos Tábara, Fatema Al-Salmi, Reza Maroofian, Amna Mohammed Al-Futaisi, Fathiya Al-Murshedi, Joanna Kennedy, Jacob O Day, Thomas Courtin, Aisha Al-Khayat, Hamid Galedari, Neda Mazaheri, Margherita Protasoni, Mark Johnson, Joseph S Leslie, Claire G Salter, Lettie E Rawlins, James Fasham, Almundher Al-Maawali, Nikol Voutsina, Perrine CharlesLaura Harrold, Boris Keren, Edmund R S Kunji, Barbara Vona, Gholamreza Jelodar, Alireza Sedaghat, Gholamreza Shariati, Henry Houlden, Andrew H Crosby, Julien Prudent, Emma L Baple

Research output: Contribution to journalArticlepeer-review

Abstract

The hereditary spastic paraplegias (HSP) are among the most genetically diverse of all Mendelian disorders. They comprise a large group of neurodegenerative diseases that may be divided into 'pure HSP' in forms of the disease primarily entailing progressive lower-limb weakness and spasticity, and 'complex HSP' when these features are accompanied by other neurological (or non-neurological) clinical signs. Here, we identified biallelic variants in the transmembrane protein 63C (TMEM63C) gene, encoding a predicted osmosensitive calcium-permeable cation channel, in individuals with hereditary spastic paraplegias associated with mild intellectual disability in some, but not all cases. Biochemical and microscopy analyses revealed that TMEM63C is an endoplasmic reticulum-localized protein, which is particularly enriched at mitochondria-endoplasmic reticulum contact sites. Functional in cellula studies indicate a role for TMEM63C in regulating both endoplasmic reticulum and mitochondrial morphologies. Together, these findings identify autosomal recessive TMEM63C variants as a cause of pure and complex HSP and add to the growing evidence of a fundamental pathomolecular role of perturbed mitochondrial-endoplasmic reticulum dynamics in motor neurone degenerative diseases.

Original languageEnglish
Pages (from-to)3095-3107
Number of pages13
JournalBrain : a journal of neurology
Volume145
Issue number9
DOIs
Publication statusPublished - Sep 14 2022

Keywords

  • Calcium Channels/genetics
  • Endoplasmic Reticulum/genetics
  • Humans
  • Mitochondria/pathology
  • Mutation
  • Spastic Paraplegia, Hereditary/genetics

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