Relationship between sodium-dependent phosphate transporter (NaPi-IIc) function and cellular vacuole formation in opossum kidney cells

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Author(s)

    • Shiozaki Yuji
    • Department of Molecular Nutrition, University of Tokushima Graduate School
    • Segawa Hiroko
    • Department of Molecular Nutrition, University of Tokushima Graduate School
    • Ohnishi Saori
    • Department of Molecular Nutrition, University of Tokushima Graduate School
    • Ohi Akiko
    • Department of Molecular Nutrition, University of Tokushima Graduate School
    • Ito Mikiko
    • Human Science and Environment, University of Hyogo Graduate School
    • Kaneko Ichiro
    • Department of Molecular Nutrition, University of Tokushima Graduate School
    • Kido Shinsuke
    • Laboratory of Clinical Nutrition, Department of Food Science and Nutrition, Kinki University Faculty of Agriculture
    • Tatsumi Sawako
    • Department of Molecular Nutrition, University of Tokushima Graduate School

Abstract

NaPi-IIc/SLC34A3 is a sodium-dependent inorganic phosphate (Pi) transporter in the renal proximal tubules and its mutations cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). In the present study, we created a specific antibody for opossum SLC34A3, NaPi-IIc (oNaPi-IIc), and analyzed its localization and regulation in opossum kidney cells (a tissue culture model of proximal tubular cells). Immunoreactive oNaPi-IIc protein levels increased during the proliferative phase and decreased during differentiation. Moreover, stimulating cell growth upregulated oNaPi-IIc protein levels, whereas suppressing cell proliferation downregulated oNaPi-IIc protein levels. Immunocytochemistry revealed that endogenous and exogenous oNaPi-IIc proteins localized at the protrusion of the plasma membrane, which is a phosphatidylinositol 4,5-bisphosphate (PIP<sub>2</sub>) rich-membrane, and at the intracellular vacuolar membrane. Exogenous NaPi-IIc also induced cellular vacuoles and localized in the plasma membrane. The ability to form vacuoles is specific to electroneutral NaPi-IIc, and not electrogenic NaPi-IIa or NaPi-IIb. In addition, mutations of NaPi-IIc (S138F and R468W) in HHRH did not cause cellular PIP<sub>2</sub>-rich vacuoles. In conclusion, our data anticipate that NaPi-IIc may regulate PIP<sub>2</sub> production at the plasma membrane and cellular vesicle formation. J. Med. Invest. 62: 209-218, August, 2015

Journal

  • The Journal of Medical Investigation

    The Journal of Medical Investigation 62(3.4), 209-218, 2015

    Faculty of Medicine Tokushima University

Codes

  • NII Article ID (NAID)
    130005099143
  • NII NACSIS-CAT ID (NCID)
    AA11166929
  • Text Lang
    ENG
  • Article Type
    journal article
  • ISSN
    1343-1420
  • Data Source
    IR  J-STAGE 
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