The function of Ensembl gene identifier ENSG00000186866 (POFUT2, protein O-fucosyltransferase 2) is as follows. GDP-fucose protein O-fucosyltransferase involved in one of the two pathways responsible for protein O-linked fucosylation, a unique post-translational modification of cysteine-knotted proteins that regulates various biological functions. This pathway targets proteins with Thrombospondin type-1 (TSP1) repeats (TSR) in the endoplasmic reticulum. Catalyzes the reaction that attaches fucose through an O-glycosidic linkage to a conserved serine or threonine residue in the consensus sequence C1-X-X-S/T-C2 of thrombospondin type I repeats (TSRs) where C1 and C2 are the first and second cysteines of the repeat, respectively (PubMed:22588082). O-fucosylates members of several protein families including the ADAMTS, the thrombospondin (TSP) and spondin families (Probable) (PubMed:17395588). Required for the proper secretion of ADAMTS family members such as ADAMTSL1 and ADAMTS13 (PubMed:17395588, PubMed:17395589). The O-fucosylation of TSRs is also required for restricting epithelial to mesenchymal transition (EMT), maintaining the correct patterning of mesoderm and localization of the definite endoderm (By similarity). {ECO:0000250|UniProtKB:Q8VHI3, ECO:0000269|PubMed:17395588, ECO:0000269|PubMed:17395589, ECO:0000269|PubMed:22588082, ECO:0000305|PubMed:11067851, ECO:0000305|PubMed:16464858}.