Journal of Molecular Neuroscience

, Volume 38, Issue 1, pp 19–30

Effects of Ubiquilin 1 on the Unfolded Protein Response

  • Alice Lu
  • Mikko Hiltunen
  • Donna M. Romano
  • Hilkka Soininen
  • Bradley T. Hyman
  • Lars Bertram
  • Rudolph E. Tanzi
Article

DOI: 10.1007/s12031-008-9155-6

Cite this article as:
Lu, A., Hiltunen, M., Romano, D.M. et al. J Mol Neurosci (2009) 38: 19. doi:10.1007/s12031-008-9155-6
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Abstract

Previous studies have implicated the unfolded protein response (UPR) in the pathogenesis of Alzheimer’s disease (AD). We previously reported that DNA variants in the ubiquilin 1 (UBQLN1) gene increase the risk for AD. Since UBQLN1 has been shown to play a role in the UPR, we assessed the effects of overexpression and downregulation of UBQLN1 splice variants during tunicamycin-induced ER stress. In addition to previously described transcript variants, TV1 and TV2, we identified two novel transcript variants of UBQLN1 in brain: TV3 (lacking exons 2–4) and TV4 (lacking exon 4). Overexpression of TV1–3, but not TV4 significantly decreased the mRNA induction of UPR-inducible genes, C/EBP homologous protein (CHOP), BiP/GRP78, and protein disulfide isomerase (PDI) during the UPR. Stable overexpression of TV1–3, but not TV4, also significantly decreased the induction of CHOP protein and increased cell viability during the UPR. In contrast, downregulation of UBQLN1 did not affect CHOP mRNA induction, but instead increased PDI mRNA levels. These findings suggest that overexpression UBQLN1 transcript variants TV1–3, but not TV4, exert a protective effect during the UPR by attenuating CHOP induction and potentially increasing cell viability.

Keywords

UBQLN1Ubiquilin 1UPRUnfolded protein responseCHOPC/EBP homologous proteinPDIProtein disulfide isomeraseBiP/GRP78ADAlzheimer’s disease

Copyright information

© Humana Press Inc. 2008

Authors and Affiliations

  • Alice Lu
    • 1
    • 2
  • Mikko Hiltunen
    • 1
    • 3
    • 4
  • Donna M. Romano
    • 1
  • Hilkka Soininen
    • 3
    • 4
  • Bradley T. Hyman
    • 5
  • Lars Bertram
    • 1
  • Rudolph E. Tanzi
    • 1
    • 2
  1. 1.Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative DiseaseMassachusetts General HospitalCharlestownUSA
  2. 2.Harvard Medical SchoolCharlestownUSA
  3. 3.Department of NeurologyUniversity HospitalKuopioFinland
  4. 4.Department of NeurologyUniversity of KuopioKuopioFinland
  5. 5.Alzheimer’s Research Unit, MassGeneral Institute for Neurodegenerative DiseaseMassachusetts General HospitalCharlestownUSA