Fucosyltransferases

Fucosyltransferases are a family of glycosyltransferase enzymes that catalyze the transfer of fucose from GDP-fucose to acceptor carbohydrates on glycoproteins and glycosphingolipids, creating fucosylated glycans. They function primarily in the Golgi apparatus and modify a broad range of glycans on cell surfaces and secreted proteins, influencing cell–cell interactions and signaling.

Based on the glycosidic linkage they form, many fucosyltransferases are categorized as alpha-1,2-, alpha-1,3/4-, or alpha-1,6-fucosyltransferases. In humans, FUT1 and FUT2 generate alpha-1,2 fucosylation that gives rise to the H antigen; FUT3 and related enzymes generate Lewis antigens by alpha-1,3/4 fucosylation; FUT8 adds fucose in alpha-1,6 linkage to the innermost GlcNAc of N-glycans (core fucosylation).

Other family members, including FUT4, FUT5, FUT6, FUT7, and FUT9, contribute additional alpha-1,3/4 fucosylations on diverse glycan substrates, shaping mucin glycosylation patterns and cell adhesion epitopes.

Biological roles of fucosyltransferases include regulation of blood group antigen expression, leukocyte trafficking through selectin ligands, mucin biology, and modulation of receptor function. Core fucosylation by FUT8, for example, can influence signaling and antibody activity.

Genetic variation in FUT genes affects phenotypes such as secretor status (FUT2 nonsecretors) and has been linked to infection susceptibility, microbiome composition, and inflammatory or neoplastic processes. In development and immunity, altered fucosylation patterns can impact tissue organization and host–pathogen interactions.