title: Osmotic stress induces the phosphorylation of WNK4 Ser575 via the p38MAPK-MK pathway.
abstract: The With No lysine [K] (WNK)-Ste20-related proline/alanine-rich kinase (SPAK)/oxidative stress-responsive kinase 1 (OSR1) pathway has been reported to be a crucial signaling pathway for triggering pseudohypoaldosteronism type II (PHAII), an autosomal dominant hereditary disease that is characterized by hypertension. However, the molecular mechanism(s) by which the WNK-SPAK/OSR1 pathway is regulated remain unclear. In this report, we identified WNK4 as an interacting partner of a recently identified MAP3K, apoptosis signal-regulating kinase 3 (ASK3). We found that WNK4 is phosphorylated in an ASK3 kinase activity-dependent manner. By exploring the ASK3-dependent phosphorylation sites, we identified Ser575 as a novel phosphorylation site in WNK4 by LC-MS/MS analysis. ASK3-dependent WNK4 Ser575 phosphorylation was mediated by the p38MAPK-MAPK-activated protein kinase (MK) pathway. Osmotic stress, as well as hypotonic low-chloride stimulation, increased WNK4 Ser575 phosphorylation via the p38MAPK-MK pathway. ASK3 was required for the p38MAPK activation induced by hypotonic stimulation but was not required for that induced by hypertonic stimulation or hypotonic low-chloride stimulation. Our results suggest that the p38MAPK-MK pathway might regulate WNK4 in an osmotic stress-dependent manner but its upstream regulators might be divergent depending on the types of osmotic stimuli.
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.|Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Maruyama
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Yumie
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Umeda
authors.affiliation: Centre de Recherche sur l'Inflammation, UMRS 1149, Université Paris 7, site Bichat, 75018, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Vandewalle
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.|Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ichijo
authors.affiliation: Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Naguro
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D004789:Enzyme Activation; D015870:Gene Expression; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins; D009997:Osmotic Pressure; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids; D002352:Carrier Proteins; C489837:KLHL3 protein, human; D008840:Microfilament Proteins; D017346:Protein Serine-Threonine Kinases; C433806:WNK4 protein, human; D048051:p38 Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C550123:MAP3K15 protein, human