Antiporter transporting nucleotide sugars such as UDP-N- acetylglucosamine (UDP-GlcNAc), UDP-glucose (UDP-Glc) and GDP- mannose (GDP-Man) pooled in the cytosol into the lumen of the Golgi in exchange for the corresponding nucleosides monophosphates (UMP for UDP-sugars and GMP for GDP-sugars). May take part in heparan sulfate synthesis by supplying UDP-Glc-NAc, the donor substrate, and thus be involved in growth factor signaling.
