Interactions with WNK (With No Lysine) Family Members Regulate Oxidative Stress Response 1 and Ion Co-transporter Activity
| Autor: | Katherine Luby-Phelps, Svetlana Earnest, Szu Wei Tu, Samarpita Sengupta, Melanie H. Cobb, Kyle Wedin, Steve Stippec |
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| Rok vydání: | 2012 |
| Předmět: |
Cytoplasm
Sodium-Potassium-Chloride Symporters Immunoprecipitation Amino Acid Motifs Green Fluorescent Proteins Hypertonic Solutions Immunoblotting Protein Serine-Threonine Kinases Biology Biochemistry Minor Histocompatibility Antigens WNK Lysine-Deficient Protein Kinase 1 Animals Humans Solute Carrier Family 12 Member 2 Amino Acid Sequence Molecular Biology Ion transporter Solute Carrier Family 12 Member 1 Protein-Serine-Threonine Kinases Kinase Intracellular Signaling Peptides and Proteins Cell Biology WNK1 Rats Transport protein Cell biology Isoenzymes Protein Transport nervous system Hypotonic Solutions Microscopy Fluorescence Phosphorylation RNA Interference Signal Transduction Fluorescence Recovery After Photobleaching HeLa Cells Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 287:37868-37879 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m112.398750 |
| Popis: | Two of the four WNK (with no lysine (K)) protein kinases are associated with a heritable form of ion imbalance culminating in hypertension. WNK1 affects ion transport in part through activation of the closely related Ste20 family protein kinases oxidative stress-responsive 1 (OSR1) and STE20/SPS1-related proline-, alanine-rich kinase (SPAK). Once activated by WNK1, OSR1 and SPAK phosphorylate and stimulate the sodium, potassium, two chloride co-transporters, NKCC1 and NKCC2, and also affect other related ion co-transporters. We find that WNK1 and OSR1 co-localize on cytoplasmic puncta in HeLa and other cell types. We show that the C-terminal region of WNK1 including a coiled coil is sufficient to localize the fragment in a manner similar to the full-length protein, but some other fragments lacking this region are mislocalized. Photobleaching experiments indicate that both hypertonic and hypotonic conditions reduce the mobility of GFP-WNK1 in cells. The four WNK family members can phosphorylate the activation loop of OSR1 to increase its activity with similar kinetic constants. C-terminal fragments of WNK1 that contain three RFXV interaction motifs can bind OSR1, block activation of OSR1 by sorbitol, and prevent the OSR1-induced enhancement of ion co-transporter activity in cells, further supporting the conclusion that association with WNK1 is required for OSR1 activation and function at least in some contexts. C-terminal WNK1 fragments can be phosphorylated by OSR1, suggesting that OSR1 catalyzes feedback phosphorylation of WNK1. |
| Databáze: | OpenAIRE |
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