CMP Sialic Acid Transporter (CMPST)

CMPST is found in the membrane of the Golgi apparatus, where it transports nucleotide sugars into the Golgi. One such nucleotide sugar is CMP-sialic acid, which is imported into the Golgi by the encoded protein and subsequently glycosylated. Defects in this gene are a cause of congenital disorder of glycosylation type 2F (CDG2F). Two transcript variants encoding different isoforms have been found for this gene.The deduced 337-amino acid SLC35A1 protein has a molecular mass of approximately 29 kD and is approximately 65% identical to SLC35A2. Immunofluorescence microscopy demonstrated expression in microsomal vesicles and in the Golgi region, with the C terminus exposed to the cytosol. Northern blot analysis revealed ubiquitous expression of a 2.0-kb transcript.