fucosyltransferase

Fucosyltransferases are enzymes that catalyze the transfer of fucose from GDP-fucose to specific acceptor molecules, producing fucosylated glycans or glycoproteins. In humans they are encoded by several FUT genes and are predominantly type II membrane proteins resident in the Golgi apparatus, with a short cytosolic tail and a single transmembrane helix followed by a luminal catalytic domain.

They differ in linkage specificity and acceptor preference. The best-characterized human enzymes include FUT1 and FUT2 (alpha1,2-fucosyltransferases) that synthesize the H antigen on glycoproteins and glycolipids; FUT3, FUT4, FUT5, FUT6, FUT7 generate Lewis-type antigens via α1,3/4 linkages; FUT8 is the sole known enzyme for core fucosylation, adding fucose in α1,6-linkage to the innermost GlcNAc of N-glycans. Additional FUTs contribute to tissue-specific fucosylation patterns.

Donor substrate GDP-fucose; acceptor substrates include N-acetyllactosamine-containing glycans on glycoproteins and glycolipids; product: fucosylated structures such as H, Lewis, and core-fucosylated N-glycans. These enzymes are part of the glycosylation machinery and influence cell-cell interactions, selectin binding, and immune recognition.

Biological and clinical relevance: Fucosylation patterns affect leukocyte trafficking, pathogen binding, and tumor behavior. FUT2 secretor status modulates susceptibility to norovirus and impacts gut microbiota composition; altered fucosylation is observed in various cancers and inflammatory diseases. Research uses gene knockout, overexpression, and glycan profiling to understand function.