The protein encoded by this gene catalyzes the O-sulfation of tyrosine residues within acidic regions of proteins. The encoded protein is a type II integral membrane protein found in the Golgi body. Alternative splicing produces multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2018] see less The protein encoded by this gene catalyzes the O-sulfation of tyrosine residues within acidic regions of proteins. The encoded protein is a type II integral membrane protein found in the Golgi body. Alternative splicing produces multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2018]