title: The European Eel NCCβ Gene Encodes a Thiazide-resistant Na-Cl Cotransporter.
abstract: The thiazide-sensitive Na-Cl cotransporter (NCC) is the major pathway for salt reabsorption in the mammalian distal convoluted tubule. NCC plays a key role in the regulation of blood pressure. Its inhibition with thiazides constitutes the primary baseline therapy for arterial hypertension. However, the thiazide-binding site in NCC is unknown. Mammals have only one gene encoding for NCC. The eel, however, contains a duplicate gene. NCCα is an ortholog of mammalian NCC and is expressed in the kidney. NCCβ is present in the apical membrane of the rectum. Here we cloned and functionally characterized NCCβ from the European eel. The cRNA encodes a 1043-amino acid membrane protein that, when expressed in Xenopus oocytes, functions as an Na-Cl cotransporter with two major characteristics, making it different from other known NCCs. First, eel NCCβ is resistant to thiazides. Single-point mutagenesis supports that the absence of thiazide inhibition is, at least in part, due to the substitution of a conserved serine for a cysteine at position 379. Second, NCCβ is not activated by low-chloride hypotonic stress, although the unique Ste20-related proline alanine-rich kinase (SPAK) binding site in the amino-terminal domain is conserved. Thus, NCCβ exhibits significant functional differences from NCCs that could be helpful in defining several aspects of the structure-function relationship of this important cotransporter.
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico.
authors: Erika
authors: E
authors: Moreno
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico.
authors: Consuelo
authors: C
authors: Plata
authors: the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14080 Mexico City, Mexico.
authors: Alejandro
authors: A
authors: Rodríguez-Gama
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico.|the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14080 Mexico City, Mexico.
authors: Eduardo R
authors: ER
authors: Argaiz
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico.|the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14080 Mexico City, Mexico.
authors: Norma
authors: N
authors: Vázquez
authors: the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14080 Mexico City, Mexico.
authors: Karla
authors: K
authors: Leyva-Ríos
authors: the Department of Physiology, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510 Coyoacan, Mexico City, Mexico.
authors: León
authors: L
authors: Islas
authors: the Biology Department, Georgia Southern University, Statesboro, Georgia 30460.
authors: Christopher
authors: C
authors: Cutler
authors: the Escuela de Medicina, Universidad Panamericana, 03920 Mexico City, Mexico.
authors: Diana
authors: D
authors: Pacheco-Alvarez
authors: the Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Tlalpan, 14080 Mexico City, Mexico, and.
authors: Adriana
authors: A
authors: Mercado
authors: the School of Medicine, Universidad Autónoma del Estado de Hidalgo, 42034 Pachuca, Hidalgo, México.
authors: Raquel
authors: R
authors: Cariño-Cortés
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico.
authors: María
authors: M
authors: Castañeda-Bueno
authors: From the Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, 14080 Mexico City, Mexico, gamba@biomedicas.unam.mx.|the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14080 Mexico City, Mexico.
authors: Gerardo
authors: G
authors: Gamba
mesh_terms: D000818:Animals; D004351:Drug Resistance / Q000187:drug effects*; D004524:Eels / Q000235:genetics / Q000378:metabolism*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009865:Oocytes; D051381:Rats; D049993:Sodium Chloride Symporter Inhibitors / Q000494:pharmacology*; D049992:Sodium Chloride Symporters / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D029941:Fish Proteins; D049993:Sodium Chloride Symporter Inhibitors; D049992:Sodium Chloride Symporters
keywords: cardiovascular disease; renal physiology; sodium transport; structure-function; transporter