title: Immunolocalization of WNK4 in mouse kidney.
abstract: Initial reports claim that WNK4 localization is mainly at intercellular junctions of distal convoluted tubules (DCT) and cortical collecting ducts (CCD) in the kidney. However, we recently clarified the major targets of WNK4 kinase to be the OSR1/SPAK kinases and the Na-Cl co-transporter (NCC), an apical membrane protein in the DCT, thus raising the question of whether the cellular localization of WNK4 is at intercellular junctions. In this study, we re-evaluate the intrarenal and intracellular immunolocalization of WNK4 in the mouse kidney using a newly generated anti-WNK4 antibody. By performing double immunofluorescence of WNK4 with several nephron-segment-specific markers, we have found that WNK4 is present in podocytes in glomeruli, the cortical thick ascending limb of Henle's loop including macula densa, and the medullary collecting ducts (MCD), in addition to the previously identified nephron segments, i.e., DCT and CCD. These results are consistent with the finding that WNK4 constitutes a kinase cascade with OSR1/SPAK and NCC in the DCT, and highlights a novel role for WNK4 in nephron segments newly identified as being WNK4-positive in this study.
authors.affiliation: Department of Medicine, Kidney Center, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjyuku-ku, Tokyo, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Ohno
authors.forename: Keiko
authors.initials: K
authors.lastname: Uchida
authors.forename: Teiko
authors.initials: T
authors.lastname: Ohashi
authors.forename: Kosaku
authors.initials: K
authors.lastname: Nitta
authors.forename: Akihito
authors.initials: A
authors.lastname: Ohta
authors.forename: Motoko
authors.initials: M
authors.lastname: Chiga
authors.forename: Sei
authors.initials: S
authors.lastname: Sasaki
authors.forename: Shinichi
authors.initials: S
authors.lastname: Uchida
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D005455:Fluorescent Antibody Technique; D007668:Kidney / Q000201:enzymology* / Q000378:metabolism; D007686:Kidney Tubules, Distal / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D011955:Receptors, Drug / Q000378:metabolism; D064486:Solute Carrier Family 12, Member 3; D027981:Symporters / Q000378:metabolism
chemical_list: D011955:Receptors, Drug; C578875:Slc12a3 protein, mouse; D064486:Solute Carrier Family 12, Member 3; D027981:Symporters; C499024:Prkwnk4 protein, mouse; C486407:Stk39 protein, mouse; C534421:OXSR1 protein, mouse; D017346:Protein Serine-Threonine Kinases