SLC35B2 encodes a Golgi membrane transporter that mediates the import of 3'-phosphoadenosine 5'-phosphosulfate (PAPS), the universal sulfate donor, from the cytosol into the Golgi lumen 1. This transport function is essential for sulfation reactions, particularly proteoglycan sulfation, which is critical for skeletal and brain development 1. The protein plays important roles in innate immunity by facilitating the production of sulfated glycosaminoglycans (sGAGs) that promote STING polymerization and activation in response to DNA virus infections 23. In cancer contexts, SLC35B2 enables protein tyrosine sulfation that affects tumor progression through modulation of signaling pathways, including Hippo signaling in hepatocellular carcinoma 4 and integrin β4 stability in pancreatic adenocarcinoma 5. Clinically, biallelic pathogenic variants in SLC35B2 cause hypomyelinating leukodystrophy 26 with chondrodysplasia, characterized by growth retardation, skeletal abnormalities, and severe intellectual disability due to impaired proteoglycan sulfation 1. The gene also shows differential expression patterns in psychiatric disorders, with reduced expression in bipolar disorder that is normalized by lithium treatment 6.