A potential role for calcium / calmodulin-dependent protein kinase-related peptide in neuronal apoptosis: in vivo and in vitro evidence

Authors

  • Geert J. Schenk,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Bart Engels,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Yan-Ping Zhang,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Carlos P. Fitzsimons,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Theo Schouten,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Marieke Kruidering,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • E. Ron de Kloet,

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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  • Erno Vreugdenhil

    1. Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research (LACDR), Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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Dr E. Vreugdenhil, as above.
E-mail: vreugden@lacdr.leidenuniv.nl

Abstract

Previously, we have established that a product of the doublecortin-like kinase (DCLK) gene, DCLK-short, is cleaved by caspases during serum deprivation. Subsequently, the N-terminal cleavage product of DCLK-short facilitates apoptosis in the neuroblastoma cell line NG108. As this N-terminal cleavage product is highly homologous to calcium/calmodulin-dependent protein kinase-related peptide (CARP), another DCLK gene splice variant, we aimed to determine the possible apoptotic properties of CARP in vivo and in vitro. We report highly specific CARP expression in apoptotic granule cells in the rat dentate gyrus after adrenalectomy relative to healthy granule cells. CARP is significantly upregulated in the suprapyramidal blade of the dentate gyrus, with varying levels of upregulation, depending on the extent of adrenalectomy-induced apoptosis. Similar to the caspase-cleaved N-terminus of DCLK-short, CARP overexpression itself facilitated apoptosis in serum-deprived NG108 cells. Furthermore, CARP facilitated polymerization of tubulin in vitro and was capable of interacting with growth factor receptor-bound protein 2, an intracellular protein involved in vesicle trafficking. Together, our data demonstrate a facilitating role for CARP in the apoptotic process in granule cell populations sensitive to adrenalectomy, and suggest that this proapoptotic effect is mediated by increasing the stability of the microtubule cytoskeleton.

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