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2.A.1.14.10
Lysosomal sialate transporter (Salla disease and infantile sialate storage disease protein, Sialin, of 419 aas and 12 TMSs (Morin et al., 2004)). Also transports glucuronic acid and aspartate. Structure-function studies have identify crucial residues and substrate-induced conformational changes (Courville et al., 2010). Also called SLC17A5. The substrate binding pocket has been identified based on modeling studies (Pietrancosta et al., 2012).  NAAG (N-acetylaspartylglutamate) an abundant neuropeptide in the vertebrate nervous system that is released from synaptic terminals in a calcium-dependent manner and acts as an agonist at the type II metabotropic glutamate receptor mGluR3, is transported into synaptic vesicles before it is secreted. Lodder-Gadaczek et al. 2013 demonstrate that vesicular uptake of NAAG and the related peptide NAAG2 (N-acetylaspartylglutamylglutamate) is mediated by sialin (SLC17A5). Sialin is probably the only vesicular transporter for NAAG and NAAG2, because transport of both peptides was not detectable in vesicles isolated from sialin-deficient mice.  Sialin also transports nitrate in the plasma membrane of salivary glands (Qin et al. 2012). Sialin interacts with nitrate and participates in the regulation of NO production and cell biological functions for body homeostasis (Wang and Qin 2022). Sialin mediates the flux of sialic acid from lysosomes to the cytoplasm (Li et al. 2022).

Accession Number:Q9NRA2
Protein Name:Sialin
Length:495
Molecular Weight:54640.00
Species: [9606]
Number of TMSs:12
Location1 / Topology2 / Orientation3: Lysosome membrane1 / Multi-pass membrane protein2
Substrate N-acetyl-beta-neuraminic acid

Cross database links:

RefSeq: NP_036566.1   
Entrez Gene ID: 26503   
Pfam: PF07690   
OMIM: 236750  phenotype
269920  phenotype
604322  gene
604369  phenotype
KEGG: hsa:26503    hsa:26503   

Gene Ontology

GO:0005887 C:integral to plasma membrane
GO:0005765 C:lysosomal membrane
GO:0005624 C:membrane fraction
GO:0005351 F:sugar:hydrogen symporter activity
GO:0006820 P:anion transport
GO:0055085 P:transmembrane transport
GO:0016023 C:cytoplasmic membrane-bounded vesicle
GO:0015136 F:sialic acid transmembrane transporter activity

References (15)

[1] “Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis.”  Fu C.et.al.   11751519
[2] “A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases.”  Verheijen F.W.et.al.   10581036
[3] “Complete sequencing and characterization of 21,243 full-length human cDNAs.”  Ota T.et.al.   14702039
[4] “The DNA sequence and analysis of human chromosome 6.”  Mungall A.J.et.al.   14574404
[5] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[6] “The spectrum of SLC17A5-gene mutations resulting in free sialic acid-storage diseases indicates some genotype-phenotype correlation.”  Aula N.et.al.   10947946
[7] “Sialic acid storage disease of the Salla phenotype in American monozygous twin female sibs.”  Martin R.A.et.al.   12794687
[8] “Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis.”  Fu C.et.al.   11751519
[9] “A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases.”  Verheijen F.W.et.al.   10581036
[10] “Complete sequencing and characterization of 21,243 full-length human cDNAs.”  Ota T.et.al.   14702039
[11] “The DNA sequence and analysis of human chromosome 6.”  Mungall A.J.et.al.   14574404
[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] “Integral and associated lysosomal membrane proteins.”  Schroeder B.et.al.   17897319
[14] “The spectrum of SLC17A5-gene mutations resulting in free sialic acid-storage diseases indicates some genotype-phenotype correlation.”  Aula N.et.al.   10947946
[15] “Sialic acid storage disease of the Salla phenotype in American monozygous twin female sibs.”  Martin R.A.et.al.   12794687

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MRSPVRDLAR NDGEESTDRT PLLPGAPRAE AAPVCCSARY NLAILAFFGF FIVYALRVNL 
61:	SVALVDMVDS NTTLEDNRTS KACPEHSAPI KVHHNQTGKK YQWDAETQGW ILGSFFYGYI 
121:	ITQIPGGYVA SKIGGKMLLG FGILGTAVLT LFTPIAADLG VGPLIVLRAL EGLGEGVTFP 
181:	AMHAMWSSWA PPLERSKLLS ISYAGAQLGT VISLPLSGII CYYMNWTYVF YFFGTIGIFW 
241:	FLLWIWLVSD TPQKHKRISH YEKEYILSSL RNQLSSQKSV PWVPILKSLP LWAIVVAHFS 
301:	YNWTFYTLLT LLPTYMKEIL RFNVQENGFL SSLPYLGSWL CMILSGQAAD NLRAKWNFST 
361:	LCVRRIFSLI GMIGPAVFLV AAGFIGCDYS LAVAFLTIST TLGGFCSSGF SINHLDIAPS 
421:	YAGILLGITN TFATIPGMVG PVIAKSLTPD NTVGEWQTVF YIAAAINVFG AIFFTLFAKG 
481:	EVQNWALNDH HGHRH