Primary structure and functional expression of a cDNA encoding the thiazide-sensitive, electroneutral sodium-chloride cotransporter.
Electroneutral Na+:Cl- cotransport systems are involved in a number of important physiological processes including salt absorption and secretion by epithelia and cell volume regulation. One group of Na+:Cl- cotransporters is specifically inhibited by the benzothiadiazine (thiazide) class of diuretic agents and can be distinguished from Na+:K+:2Cl- cotransporters based on a lack of K+ requirement and insensitivity to sulfamoylbenzoic acid diruetics like bumetanide. We report here the isolation of a cDNA encoding a thiazide-sensitive, electroneutral sodium-chloride cotransporter from the winter flounder urinary bladder using an expression cloning strategy. The pharmacological and kinetic characteristics of the cloned cotransporter are consistent with the properties of native thiazide-sensitive sodium-chloride cotransporters in teleost urinary bladder and mammalian renal distal tubule epithelia. The nucleotide sequence predicts a protein of 1023 amino acids (112 kDa) with 12 putative membrane-spanning regions, which is not related to other previously cloned sodium or chloride transporters. Northern hybridization shows two different gene products: a 3.7-kb mRNA localized only to the urinary bladder and a 3.0-kb mRNA present in several non-bladder/kidney tissues.
Gamba
G
G
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
Saltzberg
S N
SN
Lombardi
M
M
Miyanoshita
A
A
Lytton
J
J
Hediger
M A
MA
Brenner
B M
BM
Hebert
S C
SC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001581:Benzothiadiazines / Q000494:pharmacology*; D002352:Carrier Proteins / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D005432:Flounder; D007422:Intestines / Q000502:physiology; D007700:Kinetics; D008961:Models, Structural; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D016366:Open Reading Frames; D009928:Organ Specificity; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D049992:Sodium Chloride Symporters; D027981:Symporters; D001743:Urinary Bladder / Q000502:physiology*; D014982:Xenopus laevis
D001581:Benzothiadiazines; D002352:Carrier Proteins; D011994:Recombinant Proteins; D049992:Sodium Chloride Symporters; D027981:Symporters; D004247:DNA; D012964:Sodium