ORAI1 Mutations with Distinct Channel Gating Defects in Tubular Aggregate Myopathy

Johann Böhm, Monica Bulla, Jill E. Urquhart, Edoardo Malfatti, Simon G. Williams, James O'Sullivan, Anastazja Szlauer, Catherine Koch, Giovanni Baranello, Marina Mora, Michela Ripolone, Raffaella Violano, Maurizio Moggio, Helen Kingston, Timothy Dawson, Christian G. DeGoede, John Nixon, Anne Boland, Jean François Deleuze, Norma RomeroWilliam G. Newman, Nicolas Demaurex, Jocelyn Laporte

Research output: Contribution to journalArticle

Abstract

Calcium (Ca2+) is a physiological key factor, and the precise modulation of free cytosolic Ca2+ levels regulates multiple cellular functions. Store-operated Ca2+ entry (SOCE) is a major mechanism controlling Ca2+ homeostasis, and is mediated by the concerted activity of the Ca2+ sensor STIM1 and the Ca2+ channel ORAI1. Dominant gain-of-function mutations in STIM1 or ORAI1 cause tubular aggregate myopathy (TAM) or Stormorken syndrome, whereas recessive loss-of-function mutations are associated with immunodeficiency. Here, we report the identification and functional characterization of novel ORAI1 mutations in TAM patients. We assess basal activity and SOCE of the mutant ORAI1 channels, and we demonstrate that the G98S and V107M mutations generate constitutively permeable ORAI1 channels, whereas T184M alters the channel permeability only in the presence of STIM1. These data indicate a mutation-dependent pathomechanism and a genotype/phenotype correlation, as the ORAI1 mutations associated with the most severe symptoms induce the strongest functional cellular effect. Examination of the non-muscle features of our patients strongly suggests that TAM and Stormorken syndrome are spectra of the same disease. Overall, our results emphasize the importance of SOCE in skeletal muscle physiology, and provide new insights in the pathomechanisms involving aberrant Ca2+ homeostasis and leading to muscle dysfunction.

Original languageEnglish
Pages (from-to)426-438
Number of pages13
JournalHuman Mutation
Volume38
Issue number4
DOIs
Publication statusPublished - Apr 1 2017

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Keywords

  • calcium
  • ORAI1
  • SOCE
  • STIM1
  • Stormorken syndrome
  • tubular aggregate myopathy

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

Cite this

Böhm, J., Bulla, M., Urquhart, J. E., Malfatti, E., Williams, S. G., O'Sullivan, J., Szlauer, A., Koch, C., Baranello, G., Mora, M., Ripolone, M., Violano, R., Moggio, M., Kingston, H., Dawson, T., DeGoede, C. G., Nixon, J., Boland, A., Deleuze, J. F., ... Laporte, J. (2017). ORAI1 Mutations with Distinct Channel Gating Defects in Tubular Aggregate Myopathy. Human Mutation, 38(4), 426-438. https://doi.org/10.1002/humu.23172