Search
sodium bicarbonate cotransporter 3 (sodium bicarbonate cotransporter 2, sodium bicarbonate cotransporter 2b, bicarbonate transporter, solute carrier family 4 member 7, SLC4A7, BT, NBC2, NBC2B, NBC3, SBC2, SLC4A6)
Function:
1) electroneutral Na+ & HCO3- dependent cotransporter with a Na+:HCO3- 1:1 stoichiometry
2) regulates intracellular pH
3) bicarbonate salvage in secretory epithelia (putative)
4) Na+ channel activity (putative)
5) transporter activity is regulated by carbonic anhydrase 2, cAMP & PKA; insensitive to stilbene
6) interacts with CFTR through SLC9A3R1/EBP50
7) interacts with USH1C
8) forms a complex with ATP6V1B1 & SLC9A3R1/EBP50
9) PDZ-binding motif mediates interaction with the CFTR, SLC9A3R1/EBP50 complex & USH1C
10) interacts with CA2/carbonic anhydrase 2 (pH dependent)
Kinetic parameters:
- KM=24 mM for external Na+
Compartment:
- cell membrane, basolateral cell membrane,
- apical cell membrane ?
- localizes to the stereocilia of cochlear outer hair cells & to lateral membrane of cochlear inner hair cells
Alternative splicing: named isoforms=5
Expression:
- highly expressed in testis, spleen
- expressed in retina, colon, small intestine, ovary, thymus, prostate, muscle, heart, kidney
- isoform 1 is expressed in skeletal muscle, heart muscle
General
glycoprotein
phosphoprotein
solute carrier family 4 (SLC4, SLC4A)
transmembrane 11e protein
Properties
SIZE: MW = 136 kD
entity length = 1214 aa
COMPARTMENT: cellular membrane
MOTIF: exoplasmic domain {1-608}
MOTIF: N-glycosylation site {N171}
N-glycosylation site {N269}
N-glycosylation site {N398}
N-glycosylation site {N406}
transmembrane domain {609-629}
cytoplasmic loop {630-637}
transmembrane domain {638-658}
exoplasmic loop {659-695}
transmembrane domain {696-716}
cytoplasmic loop {717-725}
transmembrane domain {726-746}
exoplasmic loop {747-817}
MOTIF: N-glycosylation site {N786}
transmembrane domain {818-838}
cytoplasmic loop {839-861}
transmembrane domain {862-882}
exoplasmic loop {883-908}
transmembrane domain {909-929}
cytoplasmic loop {930-954}
transmembrane domain {955-975}
exoplasmic loop {976-1011}
transmembrane domain {1012-1032}
cytoplasmic loop {1033-1034}
transmembrane domain {1035-1055}
exoplasmic loop {1056-1092}
transmembrane domain {1093-1113}
cytoplasmic domain {1114-1214}
MOTIF: binding site
SITE: 1134-1136
FOR-BINDING-OF: carbonic anhydrase-2
PDZ recognition motif
NAME: PDZ recognition motif
SITE: 1211-1214
FOR-BINDING-VIA: PDZ domain
Ser phosphorylation site {S1213}
Database Correlations
OMIM 603353
UniProt Q9Y6M7
Pfam PF00955
References
UniProt :accession Q9Y6M7