An apical expression signal of the renal type IIc Na+-dependent phosphate cotransporter in renal epithelial cells
| Autor: | Yoko Uehata, Akihiro Kamahara, Ken-ichi Miyamoto, Masae Sakata, Akiko Ohi, Aya Sakurai, Natsumi Kangawa, Sakiko Sugino, Hiroko Segawa, Takashi Nishiyama, Sawako Tatsumi, Yutaka Taketani, Keiji Hayashi, Mikiko Ito, Masashi Kuwahata |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
medicine.medical_specialty
Swine Physiology Recombinant Fusion Proteins Amino Acid Motifs Green Fluorescent Proteins Molecular Sequence Data Sodium-Phosphate Cotransporter Proteins Type IIc Protein Sorting Signals Biology Kidney Sodium-Phosphate Cotransporter Proteins Type IIa Transfection Sodium-Phosphate Cotransporter Proteins Type IIb Mice Dogs Internal medicine Cell polarity medicine Animals Humans Biotinylation Amino Acid Sequence Microscopy Confocal Sodium-Phosphate Cotransporter Proteins Cell Polarity Kidney metabolism Epithelial Cells Opossums Apical membrane Molecular biology Epithelium Protein Structure Tertiary Transport protein Protein Transport medicine.anatomical_structure Endocrinology Mutation LLC-PK1 Cells Caco-2 Cells Cotransporter |
| Zdroj: | American Journal of Physiology-Renal Physiology. 299:F243-F254 |
| ISSN: | 1522-1466 1931-857X |
| DOI: | 10.1152/ajprenal.00189.2009 |
| Popis: | The type IIc Na+-dependent phosphate cotransporter (NaPi-IIc) is specifically targeted to, and expressed on, the apical membrane of renal proximal tubular cells and mediates phosphate transport. In the present study, we investigated the signals that determine apical expression of NaPi-IIc with a focus on the role of the N- and the C-terminal tails of mouse NaPi-IIc in renal epithelial cells [opossum kidney (OK) and Madin-Darby canine kidney cells]. Wild-type NaPi-IIc, the cotransporter NaPi-IIa, as well as several IIa-IIc chimeras and deletion mutants, were fused to enhanced green fluorescent protein (EGFP), and their cellular localization was analyzed in polarized renal epithelial cells by confocal microscopy and by cell-surface biotinylation. Fluorescent EGFP-fused NaPi-IIc transporter proteins are correctly expressed in the apical membrane of OK cells. The apical expression of N-terminal deletion mutants (deletion of N-terminal 25, 50, or 69 amino acids) was not affected by truncation. In contrast, C-terminal deletion mutants (deletion of C-terminal 45, 50, or 62 amino acids) did not have correct apical expression. A more detailed mutational analysis indicated that a domain (amino acids WLHSL) in the cytoplasmic C terminus is required for apical expression of NaPi-IIc in renal epithelial cells. We conclude that targeting of NaPi-IIc to the apical cell surface is regulated by a unique amino acid motif in the cytoplasmic C-terminal domain. |
| Databáze: | OpenAIRE |
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