Cathepsin C Propeptide Interacts with Intestinal Alkaline Phosphatase and Heat Shock Cognate Protein 70 in Human Caco-2 Cells

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Author(s)

    • YAMADA Chiharu
    • Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School
    • OARADA Motoko
    • Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University
    • OKUMURA Yuushi
    • Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School
    • KISHI Kyoichi
    • Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School
    • NIKAWA Takeshi
    • Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School

Abstract

The oligomeric structure and the residual propeptide are distinct characteristics of cathepsin C from other members in the papain superfamily. In this study, we examined the physiological role of the cathepsin C propeptide. The stable overexpression of cathepsin C propeptide significantly decreased the activities of intestinal alkaline phosphatase (IAP) and sucrase in human Caco-2 intestinal epithelial cells, whereas it did not change the proliferation and cathepsin C activity. The overexpression of cathepsin C propeptide significantly decreased the amounts of IAP protein in differentiated Caco-2 cells, compared with the transfection of mock vector, whereas the amounts of IAP transcripts were not changed. Pulse-chase analysis confirmed that the reduction in IAP activity was due to an increase in IAP degradation, but not a decrease in IAP expression. For the mechanism of the enhanced IAP degradation, we identified proteins interacting with cathepsin C propeptide in Caco-2 cells by immunoprecipitation and mass spectrometry. Cathepsin C propeptide interacted with proteins with a molecular mass of approximately 70 kDa, including IAP and heat shock cognate protein 70. Our present results suggest that the propeptide of cathepsin C may stimulate the sorting to the lysosome, at least in part, contributing to the degradation of IAP in Caco-2 cells.<br>

Journal

  • The Journal of Physiological Sciences

    The Journal of Physiological Sciences 58(2), 105-111, 2008-04-01

    PHYSIOLOGICAL SOCIETY OF JAPAN

References:  30

Codes

  • NII Article ID (NAID)
    10022597892
  • NII NACSIS-CAT ID (NCID)
    AA12129145
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    18806546
  • NDL Article ID
    9476260
  • NDL Source Classification
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL Call No.
    Z53-D40
  • Data Source
    CJP  NDL  J-STAGE 
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