Intracellular calcium modulates the nuclear translocation of calsenilin

Authors

  • Nikhat F. Zaidi,

    1. Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital Institute for Neurodegenerative Disease and Harvard Medical School, Charlestown, Massachusetts, USA
    Search for more papers by this author
  • Emma E. Thomson,

    1. Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital Institute for Neurodegenerative Disease and Harvard Medical School, Charlestown, Massachusetts, USA
    Search for more papers by this author
  • Eun-Kyoung Choi,

    1. Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital Institute for Neurodegenerative Disease and Harvard Medical School, Charlestown, Massachusetts, USA
    Search for more papers by this author
  • Joseph D. Buxbaum,

    1. Laboratory of Molecular Neuropsychiatry, Departments of Psychiatry and Neurobiology, Mount Sinai School of Medicine, New York, New York, USA
    Search for more papers by this author
  • Wilma Wasco

    1. Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital Institute for Neurodegenerative Disease and Harvard Medical School, Charlestown, Massachusetts, USA
    Search for more papers by this author

Address correspondence and reprint request to Wilma Wasco, Genetic and Aging Research Unit, Department of Neurology, Massachusetts General Hospital Institute for Neurodegenerative Disease and Harvard Medical School, Bldg. 114, 16th Street, Charlestown, MA 02129, USA.
E-mail: wasco@helix.mgh.harvard.edu

Abstract

Calsenilin, which was originally identified as a presenilin interacting protein, has since been shown to be involved in the processing of presenilin(s), the modulation of amyloid β-peptide (Aβ) levels and apoptosis. Subsequent to its original identification, calsenilin was shown to act as a downstream regulatory element antagonist modulator (and termed DREAM), as well as to interact with and modulate A-type potassium channels (and termed KChIP3). Calsenilin is primarily a cytoplasmic protein that must translocate to the nucleus to perform its function as a transcriptional repressor. This study was designed to determine the cellular events that modulate the translocation of calsenilin from the cytoplasm to the nucleus. The nuclear translocation of calsenilin was found to be enhanced following serum deprivation. A similar effect was observed when cells were treated with pharmacological agents that directly manipulate the levels of intracellular calcium (caffeine and the calcium ionophore A23187), suggesting that the increased levels of calsenilin in the nucleus are mediated by changes in intracellular calcium. A calsenilin mutant that was incapable of binding calcium retained the ability to translocate to the nucleus. Taken together, these findings indicate that the level of intracellular calcium can modulate the nuclear translocation of calsenilin and that this process does not involve the direct binding of calcium to calsenilin.

Ancillary