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Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter
Inorganic phosphate (P(i)) is crucial for proper cellular function in all organisms. In mammals, type II Na‐Pi cotransporters encoded by members of the Slc34 gene family play major roles in the maintenance of P(i) homeostasis. However, the molecular mechanisms regulating Na‐Pi cotransporter activity...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656865/ https://www.ncbi.nlm.nih.gov/pubmed/31342668 http://dx.doi.org/10.14814/phy2.14156 |
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author | Mizutani, Natsuki Okochi, Yoshifumi Okamura, Yasushi |
author_facet | Mizutani, Natsuki Okochi, Yoshifumi Okamura, Yasushi |
author_sort | Mizutani, Natsuki |
collection | PubMed |
description | Inorganic phosphate (P(i)) is crucial for proper cellular function in all organisms. In mammals, type II Na‐Pi cotransporters encoded by members of the Slc34 gene family play major roles in the maintenance of P(i) homeostasis. However, the molecular mechanisms regulating Na‐Pi cotransporter activity within the plasma membrane are largely unknown. In the present study, we used two approaches to examine the effect of changing plasma membrane phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P(2)) levels on the activities of two electrogenic Na‐Pi cotransporters, NaPi‐IIa and NaPi‐IIb. To deplete plasma membrane PI(4,5)P(2) in Xenopus oocytes, we utilized Ciona intestinalis voltage‐sensing phosphatase (Ci‐VSP), which dephosphorylates PI(4,5)P(2) to phosphatidylinositol 4‐phosphate (PI(4)P). Upon activation of Ci‐VSP, NaPi‐IIb currents were significantly decreased, whereas NaPi‐IIa currents were unaffected. We also used the rapamycin‐inducible Pseudojanin (PJ) system to deplete both PI(4,5)P(2) and PI(4)P from the plasma membrane of cultured Neuro 2a cells. Depletion of PI(4,5)P(2) and PI(4)P using PJ significantly reduced NaPi‐IIb activity, but NaPi‐IIa activity was unaffected, which excluded the possibility that NaPi‐IIa is equally sensitive to PI(4,5)P(2) and PI(4)P. These results indicate that NaPi‐IIb activity is regulated by PI(4,5)P(2), whereas NaPi‐IIa is not sensitive to either PI(4,5)P(2) or PI(4)P. In addition, patch clamp recording of NaPi‐IIa and NaPi‐IIb currents in cultured mammalian cells enabled kinetic analysis with higher temporal resolution, revealing their distinct kinetic properties. |
format | Online Article Text |
id | pubmed-6656865 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-66568652019-07-31 Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter Mizutani, Natsuki Okochi, Yoshifumi Okamura, Yasushi Physiol Rep Original Research Inorganic phosphate (P(i)) is crucial for proper cellular function in all organisms. In mammals, type II Na‐Pi cotransporters encoded by members of the Slc34 gene family play major roles in the maintenance of P(i) homeostasis. However, the molecular mechanisms regulating Na‐Pi cotransporter activity within the plasma membrane are largely unknown. In the present study, we used two approaches to examine the effect of changing plasma membrane phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P(2)) levels on the activities of two electrogenic Na‐Pi cotransporters, NaPi‐IIa and NaPi‐IIb. To deplete plasma membrane PI(4,5)P(2) in Xenopus oocytes, we utilized Ciona intestinalis voltage‐sensing phosphatase (Ci‐VSP), which dephosphorylates PI(4,5)P(2) to phosphatidylinositol 4‐phosphate (PI(4)P). Upon activation of Ci‐VSP, NaPi‐IIb currents were significantly decreased, whereas NaPi‐IIa currents were unaffected. We also used the rapamycin‐inducible Pseudojanin (PJ) system to deplete both PI(4,5)P(2) and PI(4)P from the plasma membrane of cultured Neuro 2a cells. Depletion of PI(4,5)P(2) and PI(4)P using PJ significantly reduced NaPi‐IIb activity, but NaPi‐IIa activity was unaffected, which excluded the possibility that NaPi‐IIa is equally sensitive to PI(4,5)P(2) and PI(4)P. These results indicate that NaPi‐IIb activity is regulated by PI(4,5)P(2), whereas NaPi‐IIa is not sensitive to either PI(4,5)P(2) or PI(4)P. In addition, patch clamp recording of NaPi‐IIa and NaPi‐IIb currents in cultured mammalian cells enabled kinetic analysis with higher temporal resolution, revealing their distinct kinetic properties. John Wiley and Sons Inc. 2019-07-24 /pmc/articles/PMC6656865/ /pubmed/31342668 http://dx.doi.org/10.14814/phy2.14156 Text en © 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Mizutani, Natsuki Okochi, Yoshifumi Okamura, Yasushi Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title | Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title_full | Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title_fullStr | Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title_full_unstemmed | Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title_short | Distinct functional properties of two electrogenic isoforms of the SLC34 Na‐Pi cotransporter |
title_sort | distinct functional properties of two electrogenic isoforms of the slc34 na‐pi cotransporter |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656865/ https://www.ncbi.nlm.nih.gov/pubmed/31342668 http://dx.doi.org/10.14814/phy2.14156 |
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