Sugar transporter involved in the transport of CMP-sialic acid from the cytoplasm into the Golgi. May transport important nucleotide sugars such as CMP-Kdo (2-keto-3-deoxy-D-manno-octulosonic acid) in physiological conditions. Belongs to the nucleotide-sugar transporter family. CMP-Sialate:CMP antiporter (TC 2.A.7.12) subfamily. Truncated N-terminus.