Role of AQP2 in activation of calcium entry by hypotonicity: implications in cell volume regulation
| Autor: | Luciano Galizia, Valeria Rivarola, Paula Ford, Claudia Capurro, Maria del Pilar Flamenco |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
medicine.medical_specialty
Physiology Intracellular Space Aquaporin chemistry.chemical_element Gadolinium Calcium-Transporting ATPases Calcium Transfection Calcium in biology Cell Line Cell membrane Internal medicine medicine Animals Cell Size Aquaporin 2 Chemistry Cell biology Rats medicine.anatomical_structure Endocrinology Hypotonic Solutions Cell culture Thapsigargin Duct (anatomy) Intracellular |
| Zdroj: | American journal of physiology. Renal physiology. 294(3) |
| ISSN: | 1931-857X |
| Popis: | We previously reported in a rat cortical collecting duct cell line (RCCD1) that the presence of aquaporin 2 (AQP2) in the cell membrane is critical for the rapid activation of regulatory volume decrease mechanisms (RVD) (Ford et al. Biol Cell 97: 687–697, 2005). The aim of our present work was to investigate the signaling pathway that links AQP2 to this rapid RVD activation. Since it has been previously described that hypotonic conditions induce intracellular calcium ([Ca2+]i) increases in different cell types, we tested the hypothesis that AQP2 could have a role in activation of calcium entry by hypotonicity and its implication in cell volume regulation. Using a fluorescent probe technique, we studied [Ca2+]iand cell volume changes in response to a hypotonic shock in WT-RCCD1(not expressing aquaporins) and in AQP2-RCCD1(transfected with AQP2) cells. We found that after a hypotonic shock only AQP2-RCCD1cells exhibit a substantial increase in [Ca2+]i. This [Ca2+]iincrease is strongly dependent on extracellular Ca2+and is partially inhibited by thapsigargin (1 μM) indicating that the rise in [Ca2+]ireflects both influx from the extracellular medium and release from intracellular stores. Exposure of AQP2-RCCD1cells to 100 μM gadolinium reduced the increase in [Ca2+]isuggesting the involvement of a mechanosensitive calcium channel. Furthermore, exposure of cells to all of the above described conditions impaired rapid RVD. We conclude that the expression of AQP2 in the cell membrane is critical to produce the increase in [Ca2+]iwhich is necessary to activate RVD in RCCD1cells. |
| Databáze: | OpenAIRE |
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