Cloning, tissue distribution, genomic organization, and functional characterization of NBC3, a new member of the sodium bicarbonate cotransporter family.
Previous functional studies have demonstrated that muscle intracellular pH regulation is mediated by sodium-coupled bicarbonate transport, Na+/H+ exchange, and Cl-/bicarbonate exchange. We report the cloning, sequence analysis, tissue distribution, genomic organization, and functional analysis of a new member of the sodium bicarbonate cotransporter (NBC) family, NBC3, from human skeletal muscle. mNBC3 encodes a 1214-residue polypeptide with 12 putative membrane-spanning domains. The approximately 7.8-kilobase transcript is expressed uniquely in skeletal muscle and heart. The NBC3 gene (SLC4A7) spans approximately 80 kb and is composed of 25 coding exons and 24 introns that are flanked by typical splice donor and acceptor sequences. Expression of mNBC3 cRNA in Xenopus laevis oocytes demonstrated that the protein encodes a novel stilbene-insensitive 5-(N-ethyl-N-isopropyl)-amiloride-inhibitable sodium bicarbonate cotransporter.
Pushkin
A
A
Division of Nephrology, Center for Health Sciences, UCLA School of Medicine, Los Angeles, California 90095-1698, USA.
Abuladze
N
N
Lee
I
I
Newman
D
D
Hwang
J
J
Kurtz
I
I
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D020224:Expressed Sequence Tags; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D027982:Sodium-Bicarbonate Symporters; D014982:Xenopus laevis
D002352:Carrier Proteins; D008565:Membrane Proteins; C422022:SLC4A7 protein, human; D027982:Sodium-Bicarbonate Symporters