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2.A.31.4.1
Boron transporter, NcBC1 or SLC4a11. In the absence of borate, it functions as a Na+ and OH- (H+) channel. In the presence of borate, it functions as an electrogenic Na+-coupled borate cotransporter (Park et al., 2004).  Three genetic corneal dystrophies (congenital hereditary endothelial dystrophy type 2 (CHED2), Harboyan syndrome and Fuchs endothelial corneal dystrophy (FECD) arise from mutations of the SLC4a11 gene, which cause blindness from fluid accumulation in the corneal stroma.  It can mediate water flux at a rate comparable to aquaporin in a process that is independent of solute transport (Vilas et al. 2013).  Reviewed by Patel and Parker 2015.  A 3-d homology model rationalizes vaious pathology-causing mutations (Badior et al. 2016). SLC4A11 is also a cell adhesion molecule involving extracellular loop 3, and cell adhesion defects contribute to FECD and CHED pathology (Malhotra et al. 2019). pH-dependence of Slc4a11-mediated H+ conductance is influenced by intracellular lysine residues and modified by disease-linked mutations (Quade et al. 2020).

Accession Number:Q8NBS3
Protein Name:NaBC1
Length:891
Molecular Weight:99581.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:13
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate Boride

Cross database links:

RefSeq: NP_001167561.1    NP_114423.1   
Entrez Gene ID: 83959   
Pfam: PF00955    PF00359   
OMIM: 217400  phenotype
217700  phenotype
610206  gene
KEGG: hsa:83959    hsa:83959   

Gene Ontology

GO:0016323 C:basolateral plasma membrane
GO:0016021 C:integral to membrane
GO:0015106 F:bicarbonate transmembrane transporter activity
GO:0046715 F:boron transmembrane transporter activity
GO:0015252 F:hydrogen ion channel activity
GO:0005452 F:inorganic anion exchanger activity
GO:0005272 F:sodium channel activity
GO:0005351 F:sugar:hydrogen symporter activity
GO:0015701 P:bicarbonate transport
GO:0046713 P:boron transport
GO:0030003 P:cellular cation homeostasis
GO:0009401 P:phosphoenolpyruvate-dependent sugar phospho...
GO:0015992 P:proton transport
GO:0006814 P:sodium ion transport
GO:0046715 F:borate transmembrane transporter activity
GO:0042044 P:fluid transport
GO:0009401 P:phosphoenolpyruvate-dependent sugar phosphotransferase system

References (27)

[1] “Human BTR1, a new bicarbonate transporter superfamily member and human AE4 from kidney.”  Parker M.D.et.al.   11302728
[2] “The DNA sequence and comparative analysis of human chromosome 20.”  Deloukas P.et.al.   11780052
[3] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[4] “Complete sequencing and characterization of 21,243 full-length human cDNAs.”  Ota T.et.al.   14702039
[5] “NaBC1 is a ubiquitous electrogenic Na+-coupled borate transporter essential for cellular boron homeostasis and cell growth and proliferation.”  Park M.et.al.   15525507
[6] “SLC4A11 mutations in Fuchs endothelial corneal dystrophy.”  Vithana E.N.et.al.   18024964
[7] “Mutations in sodium-borate cotransporter SLC4A11 cause recessive congenital hereditary endothelial dystrophy (CHED2).”  Vithana E.N.et.al.   16767101
[8] “Autosomal recessive corneal endothelial dystrophy (CHED2) is associated with mutations in SLC4A11.”  Jiao X.et.al.   16825429
[9] “Borate transporter SLC4A11 mutations cause both Harboyan syndrome and non-syndromic corneal endothelial dystrophy.”  Desir J.et.al.   17220209
[10] “Human BTR1, a new bicarbonate transporter superfamily member and human AE4 from kidney.”  Parker M.D.et.al.   11302728
[11] “The DNA sequence and comparative analysis of human chromosome 20.”  Deloukas P.et.al.   11780052
[12] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[13] “Complete sequencing and characterization of 21,243 full-length human cDNAs.”  Ota T.et.al.   14702039
[14] “NaBC1 is a ubiquitous electrogenic Na+-coupled borate transporter essential for cellular boron homeostasis and cell growth and proliferation.”  Park M.et.al.   15525507
[15] “SLC4A11 mutations in Fuchs endothelial corneal dystrophy.”  Vithana E.N.et.al.   18024964
[16] “Oligomerization of SLC4A11 protein and the severity of FECD and CHED2 corneal dystrophies caused by SLC4A11 mutations.”  Vilas G.L.et.al.   22072594
[17] “Mutations in sodium-borate cotransporter SLC4A11 cause recessive congenital hereditary endothelial dystrophy (CHED2).”  Vithana E.N.et.al.   16767101
[18] “Novel SLC4A11 mutations in patients with recessive congenital hereditary endothelial dystrophy (CHED2). Mutation in brief #958. Online.”  Ramprasad V.L.et.al.   17397048
[19] “Autosomal recessive corneal endothelial dystrophy (CHED2) is associated with mutations in SLC4A11.”  Jiao X.et.al.   16825429
[20] “Borate transporter SLC4A11 mutations cause both Harboyan syndrome and non-syndromic corneal endothelial dystrophy.”  Desir J.et.al.   17220209
[21] “Mutational spectrum of the SLC4A11 gene in autosomal recessive congenital hereditary endothelial dystrophy.”  Sultana A.et.al.   17679935
[22] “Identification of mutations in the SLC4A11 gene in patients with recessive congenital hereditary endothelial dystrophy.”  Hemadevi B.et.al.   18474783
[23] “Mutational spectrum of SLC4A11 in autosomal recessive CHED in Saudi Arabia.”  Aldahmesh M.A.et.al.   19369245
[24] “Novel human pathological mutations. Gene symbol: SLC4A11. Disease: Corneal endothelial dystrophy 2.”  Chai S.M.et.al.   20108384
[25] “Missense mutations in the sodium borate cotransporter SLC4A11 cause late-onset Fuchs corneal dystrophya.”  Riazuddin S.A.et.al.   20848555
[26] “SLC4A11 prevents osmotic imbalance leading to corneal endothelial dystrophy, deafness, and polyuria.”  Groger N.et.al.   20185830
[27] “Congenital hereditary endothelial dystrophy - mutation analysis of SLC4A11 and genotype-phenotype correlation in a North Indian patient cohort.”  Paliwal P.et.al.   21203343

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MSQVGGRGDR CTQEVQGLVH GAGDLSASLA ENSPTMSQNG YFEDSSYYKC DTDDTFEARE 
61:	EILGDEAFDT ANSSIVSGES IRFFVNVNLE MQATNTENEA TSGGCVLLHT SRKYLKLKNF 
121:	KEEIRAHRDL DGFLAQASIV LNETATSLDN VLRTMLRRFA RDPDNNEPNC NLDLLMAMLF 
181:	TDAGAPMRGK VHLLSDTIQG VTATVTGVRY QQSWLCIICT MKALQKRHVC ISRLVRPQNW 
241:	GENSCEVRFV ILVLAPPKMK STKTAMEVAR TFATMFSDIA FRQKLLETRT EEEFKEALVH 
301:	QRQLLTMVSH GPVAPRTKER STVSLPAHRH PEPPKCKDFV PFGKGIREDI ARRFPLYPLD 
361:	FTDGIIGKNK AVGKYITTTL FLYFACLLPT IAFGSLNDEN TDGAIDVQKT IAGQSIGGLL 
421:	YALFSGQPLV ILLTTAPLAL YIQVIRVICD DYDLDFNSFY AWTGLWNSFF LALYAFFNLS 
481:	LVMSLFKRST EEIIALFISI TFVLDAVKGT VKIFWKYYYG HYLDDYHTKR TSSLVSLSGL 
541:	GASLNASLHT ALNASFLASP TELPSATHSG QATAVLSLLI MLGTLWLGYT LYQFKKSPYL 
601:	HPCVREILSD CALPIAVLAF SLISSHGFRE IEMSKFRYNP SESPFAMAQI QSLSLRAVSG 
661:	AMGLGFLLSM LFFIEQNLVA ALVNAPENRL VKGTAYHWDL LLLAIINTGL SLFGLPWIHA 
721:	AYPHSPLHVR ALALVEERVE NGHIYDTIVN VKETRLTSLG ASVLVGLSLL LLPVPLQWIP 
781:	KPVLYGLFLY IALTSLDGNQ LVQRVALLLK EQTAYPPTHY IRRVPQRKIH YFTGLQVLQL 
841:	LLLCAFGMSS LPYMKMIFPL IMIAMIPIRY ILLPRIIEAK YLDVMDAEHR P