Transportin 1 colocalization with Fused in Sarcoma (FUS) inclusions is not characteristic for amyotrophic lateral sclerosis-FUS confirming disrupted nuclear import of mutant FUS and distinguishing it from frontotemporal lobar degeneration with FUS inclusions

C. Troakes, T. Hortobágyi, C. Vance, S. Al-Sarraj, B. Rogelj, C. E. Shaw

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16 Citations (Scopus)

Abstract

Aims: Transportin 1 (TNPO 1) is an abundant component of the Fused in Sarcoma (FUS)-immunopositive inclusions seen in a subgroup of frontotemporal lobar degeneration (FTLD-FUS). TNPO 1 has been shown to bind to the C-terminal nuclear localizing signal (NLS) of FUS and mediate its nuclear import. Amyotrophic lateral sclerosis (ALS)-linked C-terminal mutants disrupt TNPO 1 binding to the NLS and impair nuclear import in cell culture. If this held true for human ALS then we predicted that FUS inclusions in patients with C-terminal FUS mutations would not colocalize with TNPO 1. Methods: Expression of TNPO 1 and colocalization with FUS was studied in the frontal cortex of FTLD-FUS (n=3) and brain and spinal cord of ALS-FUS (n=3), ALS-C9orf72 (n=3), sporadic ALS (n=7) and controls (n=7). Expression levels and detergent solubility of TNPO 1 was measured by Western blot. Results: Aggregates of TNPO 1 were abundant and colocalized with FUS inclusions in the cortex of all FTLD-FUS cases. In contrast, no TNPO 1-positive aggregates or FUS colocalization was evident in two-thirds, ALS-FUS cases and was rare in one ALS-FUS case. Nor were they present in C9orf72 or sporadic ALS. No increase in the levels of TNPO 1 was seen in Western blots of spinal cord tissues from all ALS cases compared with controls. Conclusions: These findings confirm that C-terminal FUS mutations prevent TNPO 1 binding to the NLS, inhibiting nuclear import and promoting cytoplasmic aggregation. The presence of TNPO 1 in wild-type FUS aggregates in FTLD-FUS distinguishes the two pathologies and implicates different disease mechanisms.

Original languageEnglish
Pages (from-to)553-561
Number of pages9
JournalNeuropathology and Applied Neurobiology
Volume39
Issue number5
DOIs
Publication statusPublished - Aug 2013

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Frontotemporal Lobar Degeneration
Karyopherins
Cell Nucleus Active Transport
Amyotrophic Lateral Sclerosis
Sarcoma
Spinal Cord
Western Blotting
Mutation

Keywords

  • ALS
  • FTLD
  • FUS
  • TNPO 1
  • Transportin 1

ASJC Scopus subject areas

  • Clinical Neurology
  • Pathology and Forensic Medicine
  • Neurology
  • Histology
  • Physiology (medical)

Cite this

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title = "Transportin 1 colocalization with Fused in Sarcoma (FUS) inclusions is not characteristic for amyotrophic lateral sclerosis-FUS confirming disrupted nuclear import of mutant FUS and distinguishing it from frontotemporal lobar degeneration with FUS inclusions",
abstract = "Aims: Transportin 1 (TNPO 1) is an abundant component of the Fused in Sarcoma (FUS)-immunopositive inclusions seen in a subgroup of frontotemporal lobar degeneration (FTLD-FUS). TNPO 1 has been shown to bind to the C-terminal nuclear localizing signal (NLS) of FUS and mediate its nuclear import. Amyotrophic lateral sclerosis (ALS)-linked C-terminal mutants disrupt TNPO 1 binding to the NLS and impair nuclear import in cell culture. If this held true for human ALS then we predicted that FUS inclusions in patients with C-terminal FUS mutations would not colocalize with TNPO 1. Methods: Expression of TNPO 1 and colocalization with FUS was studied in the frontal cortex of FTLD-FUS (n=3) and brain and spinal cord of ALS-FUS (n=3), ALS-C9orf72 (n=3), sporadic ALS (n=7) and controls (n=7). Expression levels and detergent solubility of TNPO 1 was measured by Western blot. Results: Aggregates of TNPO 1 were abundant and colocalized with FUS inclusions in the cortex of all FTLD-FUS cases. In contrast, no TNPO 1-positive aggregates or FUS colocalization was evident in two-thirds, ALS-FUS cases and was rare in one ALS-FUS case. Nor were they present in C9orf72 or sporadic ALS. No increase in the levels of TNPO 1 was seen in Western blots of spinal cord tissues from all ALS cases compared with controls. Conclusions: These findings confirm that C-terminal FUS mutations prevent TNPO 1 binding to the NLS, inhibiting nuclear import and promoting cytoplasmic aggregation. The presence of TNPO 1 in wild-type FUS aggregates in FTLD-FUS distinguishes the two pathologies and implicates different disease mechanisms.",
keywords = "ALS, FTLD, FUS, TNPO 1, Transportin 1",
author = "C. Troakes and T. Hortob{\'a}gyi and C. Vance and S. Al-Sarraj and B. Rogelj and Shaw, {C. E.}",
year = "2013",
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language = "English",
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T1 - Transportin 1 colocalization with Fused in Sarcoma (FUS) inclusions is not characteristic for amyotrophic lateral sclerosis-FUS confirming disrupted nuclear import of mutant FUS and distinguishing it from frontotemporal lobar degeneration with FUS inclusions

AU - Troakes, C.

AU - Hortobágyi, T.

AU - Vance, C.

AU - Al-Sarraj, S.

AU - Rogelj, B.

AU - Shaw, C. E.

PY - 2013/8

Y1 - 2013/8

N2 - Aims: Transportin 1 (TNPO 1) is an abundant component of the Fused in Sarcoma (FUS)-immunopositive inclusions seen in a subgroup of frontotemporal lobar degeneration (FTLD-FUS). TNPO 1 has been shown to bind to the C-terminal nuclear localizing signal (NLS) of FUS and mediate its nuclear import. Amyotrophic lateral sclerosis (ALS)-linked C-terminal mutants disrupt TNPO 1 binding to the NLS and impair nuclear import in cell culture. If this held true for human ALS then we predicted that FUS inclusions in patients with C-terminal FUS mutations would not colocalize with TNPO 1. Methods: Expression of TNPO 1 and colocalization with FUS was studied in the frontal cortex of FTLD-FUS (n=3) and brain and spinal cord of ALS-FUS (n=3), ALS-C9orf72 (n=3), sporadic ALS (n=7) and controls (n=7). Expression levels and detergent solubility of TNPO 1 was measured by Western blot. Results: Aggregates of TNPO 1 were abundant and colocalized with FUS inclusions in the cortex of all FTLD-FUS cases. In contrast, no TNPO 1-positive aggregates or FUS colocalization was evident in two-thirds, ALS-FUS cases and was rare in one ALS-FUS case. Nor were they present in C9orf72 or sporadic ALS. No increase in the levels of TNPO 1 was seen in Western blots of spinal cord tissues from all ALS cases compared with controls. Conclusions: These findings confirm that C-terminal FUS mutations prevent TNPO 1 binding to the NLS, inhibiting nuclear import and promoting cytoplasmic aggregation. The presence of TNPO 1 in wild-type FUS aggregates in FTLD-FUS distinguishes the two pathologies and implicates different disease mechanisms.

AB - Aims: Transportin 1 (TNPO 1) is an abundant component of the Fused in Sarcoma (FUS)-immunopositive inclusions seen in a subgroup of frontotemporal lobar degeneration (FTLD-FUS). TNPO 1 has been shown to bind to the C-terminal nuclear localizing signal (NLS) of FUS and mediate its nuclear import. Amyotrophic lateral sclerosis (ALS)-linked C-terminal mutants disrupt TNPO 1 binding to the NLS and impair nuclear import in cell culture. If this held true for human ALS then we predicted that FUS inclusions in patients with C-terminal FUS mutations would not colocalize with TNPO 1. Methods: Expression of TNPO 1 and colocalization with FUS was studied in the frontal cortex of FTLD-FUS (n=3) and brain and spinal cord of ALS-FUS (n=3), ALS-C9orf72 (n=3), sporadic ALS (n=7) and controls (n=7). Expression levels and detergent solubility of TNPO 1 was measured by Western blot. Results: Aggregates of TNPO 1 were abundant and colocalized with FUS inclusions in the cortex of all FTLD-FUS cases. In contrast, no TNPO 1-positive aggregates or FUS colocalization was evident in two-thirds, ALS-FUS cases and was rare in one ALS-FUS case. Nor were they present in C9orf72 or sporadic ALS. No increase in the levels of TNPO 1 was seen in Western blots of spinal cord tissues from all ALS cases compared with controls. Conclusions: These findings confirm that C-terminal FUS mutations prevent TNPO 1 binding to the NLS, inhibiting nuclear import and promoting cytoplasmic aggregation. The presence of TNPO 1 in wild-type FUS aggregates in FTLD-FUS distinguishes the two pathologies and implicates different disease mechanisms.

KW - ALS

KW - FTLD

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KW - TNPO 1

KW - Transportin 1

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