O-FucT-2 adds O-fucose to thrombospondin type 1 repeats (TSRs), and appears conserved in bilateria. The O-fucosylation of TSRs appears to play a role in regulating secretion of metalloproteases of the ADAMTS superfamily. O-fucosyltransferase-like proteins are GDP-fucose dependent enzymes with similarities to the family 1 glycosyltransferases (GT1). They are soluble ER proteins that may be proteolytically cleaved from a membrane-associated preprotein, and are involved in the O-fucosylation of protein substrates, the core fucosylation of growth factor receptors, and other processes.