SLC17A5 : solute carrier family 17 member 5
Description
The SLC17A5 (solute carrier family 17 member 5) is a protein-coding gene located on chromosome 6.
The SLC17A5 gene provides instructions for producing a protein called sialin that is located mainly on the membranes of lysosomes, compartments in the cell that digest and recycle materials. Sialin moves a molecule called free sialic acid, which is produced when certain proteins and fats are broken down, out of the lysosomes to other parts of the cell. Free sialic acid means that the sialic acid is not attached (bound) to other molecules. Researchers believe that sialin may also have other functions in brain cells, in addition to those associated with the lysosomes, but these additional functions are not well understood.
SLC17A5 encodes a multifunctional anion transporter that operates via two distinct transport mechanisms: proton-coupled anion cotransport and membrane potential-dependent anion transport. It functions as an electroneutral proton-coupled acidic monosaccharide symporter, exporting glucuronic acid and free sialic acid from lysosomes. This export is driven by the lysosomal pH gradient and may regulate lysosome function and sialylated conjugate metabolism, impacting oligodendrocyte differentiation and myelinogenesis in the central nervous system. SLC17A5 also acts as an electrogenic proton-coupled nitrate symporter, transporting nitrate ions across the basolateral membrane of salivary gland acinar cells. This function contributes to nitrate clearance from serum, leading to its concentration and secretion in saliva. Additionally, SLC17A5 uses membrane potential to drive the uptake of acidic amino acids and peptides into synaptic vesicles. It is responsible for storing L-aspartate and L-glutamate in pinealocytes, as well as the vesicular uptake of N-acetyl-L-aspartyl-L-glutamate neuropeptide. These functions are involved in aspartegic-associated glutamatergic neurotransmission and the activation of metabotropic receptors that inhibit subsequent transmitter release.
SLC17A5 is also known as AST, ISSD, NSD, SD, SIALIN, SIASD, SLD, VEAT.
