Title
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Mutations in the ER-shaping protein reticulon 2 cause the axon-degenerative disorder hereditary spastic paraplegia type 12
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Author
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Abstract
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Hereditary spastic paraplegias (HSPs) are a group of genetically heterogeneous neurodegenerative conditions. They are characterized by progressive spastic paralysis of the legs as a result of selective, length-dependent degeneration of the axons of the corticospinal tract. Mutations in 3 genes encoding proteins that work together to shape the ER into sheets and tubules receptor accessory protein 1 (REEP1), atlastin-1 (ATL1), and spastin (SPAST) have been found to underlie many cases of HSP in Northern Europe and North America. Applying Sanger and exome sequencing, we have now identified 3 mutations in reticulon 2 (RTN2), which encodes a member of the reticulon family of prototypic ER-shaping proteins, in families with spastic paraplegia 12 (SPG12). These autosomal dominant mutations included a complete deletion of RTN2 and a frameshift mutation predicted to produce a highly truncated protein. Wild-type reticulon 2, but not the truncated protein potentially encoded by the frameshift allele, localized to the ER RTN2 interacted with spastin, and this interaction required a hydrophobic region in spastin that is involved in ER localization and that is predicted to form a curvature-inducing/sensing hairpin loop domain. Our results directly implicate a reticulon protein in axonopathy, show that this protein participates in a network of interactions among HSP proteins involved in ER shaping, and further support the hypothesis that abnormal ER morphogenesis is a pathogenic mechanism in HSP. |
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Language
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English
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Source (journal)
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The journal of clinical investigation. - New York, N.Y., 1924, currens
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Publication
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New York, N.Y.
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2012
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ISSN
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0021-9738
[print]
1558-8238
[online]
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DOI
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10.1172/JCI60560
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Volume/pages
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122
:2
(2012)
, p. 538-544
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ISI
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000299765800020
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Full text (Publisher's DOI)
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Full text (open access)
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