SLC17A5 cotransports Neu5Ac, H+ from lysosomal lumen to cytosol

Stable Identifier
Reaction [transition]
Homo sapiens
Proton-coupled sialic acid co-transport
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SLC17A5 encodes a lysosomal sialic acid transporter, Sialin (AST, membrane glycoprotein HP59) (Verheijen et al. 1999, Fu et al. 2001). SLC17A5 exports sialic acid (N-acetylneuraminic acid, Neu5Ac) which is derived from the degradation of glycoconjugates. This export is dependent on the proton electrochemical gradient across the lysosomal membrane. SLC17A5 is present in the pathological tumor vasculature of the lung, breast, colon, and ovary, but not in the normal vasculature, suggesting that the protein may be critical to pathological angiogenesis. Sialin is not expressed in a variety of normal tissues, but is significantly expressed in human fetal lung. Defects in SLC17A5 cause Salla disease (SD) and infantile sialic acid storage disorder (ISSD aka N-acetylneuraminic acid storage disease, NSD). These belong to the sialic acid storage disease (SASD) group and are autosomal recessive neurodegenerative disorders characterised by hypotonia, cerebellar ataxia and mental retardation in very young infants (Verheijen et al. 1999, Aula et al. 2000).

Literature References
PubMed ID Title Journal Year
10581036 A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases

Peltonen, Leena, van der Spek, PJ, Verbeek, E, Joosse, M, Galjaard, H, Aula, P, Aula, N, Havelaar, AC, Verheijen, FW, Mancini, GM, Beerens, CE

Nat Genet 1999
11751519 Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis

Shi, E, Lloyd, RS, Yakes, FM, Hellerqvist, CG, Bardhan, S, Page, DL, Carter, C, Mernaugh, RL, Yan, HP, Wang, Y, Cetateanu, ND, Venkov, C, Fu, C, Wamil, BD

Clin Cancer Res 2001
10947946 The spectrum of SLC17A5-gene mutations resulting in free sialic acid-storage diseases indicates some genotype-phenotype correlation

Peltonen, Leena, Mancini, G, Månsson, JE, Aula, P, Aula, N, Timonen, R, Verheijen, F, Salomäki, P

Am J Hum Genet 2000
Catalyst Activity

sialic acid:proton symporter activity of SLC17A5 [lysosomal membrane]

Orthologous Events
Cross References
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