Solute Carrier Family 35, Member B3 (SLC35B3)

Sulfation of a variety of molecules, including glycoproteins, proteoglycans, and glycolipids, requires 3-prime phosphoadenosine 5-prime phosphosulfate (PAPS), a high-energy form of the universal sulfate donor. SLC35B3 translocates PAPS from the cytosol or nucleus, where it is synthesized, to the Golgi lumen for use. The deduced 401-amino acid protein has a calculated molecular mass of 44.6 kD. It is a type III transmembrane protein with 9 transmembrane domains and 8 potential N-glycosylation sites. Epitope-tagged PAPST2 localized to Golgi in a transfected human colon cancer cell line. Northern blot analysis detected a 2-kb PAPST2 transcript in colon cancer cell lines and normal colon tissue. Real-time PCR detected variable expression of PAPST2 in all tissues examined, with highest levels in colon, followed by pancreas.