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Protein phosphatase 2C is responsible for VP-induced dephosphorylation of AQP2 serine 261
- Publication Year :
- 2017
- Publisher :
- American Physiological Society, 2017.
-
Abstract
- Aquaporin 2 (AQP2) trafficking is regulated by phosphorylation and dephosphorylation of serine residues in the AQP2 COOH terminus. Vasopressin (VP) binding to its receptor (V2R) leads to a cascade of events that result in phosphorylation of serine 256 (S256), S264, and S269, but dephosphorylation of S261. To identify which phosphatase is responsible for VP-induced S261 dephosphorylation, we pretreated cells with different phosphatase inhibitors before VP stimulation. Sanguinarine, a specific protein phosphatase (PP) 2C inhibitor, but not inhibitors of PP1, PP2A (okadaic acid), or PP2B (cyclosporine), abolished VP-induced S261 dephosphorylation. However, sanguinarine and VP significantly increased phosphorylation of ERK, a kinase that can phosphorylate S261; inhibition of ERK by PD98059 partially decreased baseline S261 phosphorylation. These data support a role of ERK in S261 phosphorylation but suggest that, upon VP treatment, increased phosphatase activity overcomes the increase in ERK activity, resulting in overall dephosphorylation of S261. We also found that sanguinarine abolished VP-induced S261 dephosphorylation in cells expressing mutated AQP2 S256A, suggesting that the phosphorylation state of S261 is independent of S256. Sanguinarine alone did not induce AQP2 membrane trafficking, nor did it inhibit VP-induced AQP2 membrane accumulation in cells and kidney tissues, suggesting that S261 does not play an observable role in acute AQP2 membrane accumulation. In conclusion, PP2C activity is required for S261 AQP2 dephosphorylation upon VP stimulation, which occurs independently of S256 phosphorylation. Understanding the pathways involved in modulating PP2C will help elucidate the role of S261 in cellular events involving AQP2.
- Subjects :
- 0301 basic medicine
MAPK/ERK pathway
Receptors, Vasopressin
Physiology
Swine
Vasopressins
Phosphatase
Aquaporin
Biology
Pyruvate dehydrogenase phosphatase
In Vitro Techniques
Kidney
Transfection
Dephosphorylation
Serine
Rats, Sprague-Dawley
03 medical and health sciences
0302 clinical medicine
Animals
Enzyme Inhibitors
Phosphorylation
Extracellular Signal-Regulated MAP Kinases
Vasopressin receptor
Aquaporin 2
urogenital system
Cell biology
Protein Phosphatase 2C
Protein Transport
030104 developmental biology
Biochemistry
030220 oncology & carcinogenesis
Mutation
LLC-PK1 Cells
Research Article
Signal Transduction
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....db081e187c51fe2071623eac3d0c13b8