FUT3
Description
The FUT3 (fucosyltransferase 3 (Lewis blood group)) is a protein-coding gene located on chromosome 19.
FUT3, or Galactoside 3(4)-L-fucosyltransferase, is an enzyme encoded by the FUT3 gene in humans. It belongs to the fucosyltransferase family, which catalyzes the addition of fucose to precursor polysaccharides. FUT3 specifically has alpha(1,3)-fucosyltransferase and alpha(1,4)-fucosyltransferase activities. Mutations in FUT3 are responsible for most Lewis antigen-negative phenotypes. This gene exhibits multiple alternatively spliced variants that encode the same protein.
FUT3 catalyzes the transfer of L-fucose from guanosine diphosphate-beta-L-fucose to both the subterminal N-acetyl glucosamine (GlcNAc) of type 1 chain (beta-D-Gal-(1->3)-beta-D-GlcNAc) glycolipids and oligosaccharides via an alpha(1,4) linkage, and the subterminal glucose (Glc) or GlcNAc of type 2 chain (beta-D-Gal-(1->4)-beta-D- GlcNAc) oligosaccharides via an alpha(1,3) linkage, independently of the presence of terminal alpha-L-fucosyl-(1,2) moieties on the terminal galactose of these acceptors. This activity participates in the synthesis of antigens of the Lewis blood group system, including Lewis a (Le(a)), lewis b (Le(b)), Lewis x/SSEA-1 (Le(x)) and lewis y (Le(y)) antigens. FUT3 also catalyzes the transfer of L-fucose to subterminal GlcNAc of sialyl- and disialyl-lactotetraosylceramide to produce sialyl Lewis a (sLe(a)) and disialyl Lewis a via an alpha(1,4) linkage, potentially regulating cell surface sLe(a) expression and consequently influencing adhesive properties to E-selectin, cell proliferation and migration. Additionally, FUT3 catalyzes the transfer of an L-fucose to 3'-sialyl-N-acetyllactosamine by an alpha(1,3) linkage, allowing the formation of sialyl-Lewis x structure and potentially regulating the sialyl-Lewis x surface antigen expression and consequently adhesive properties to E-selectin. FUT3 prefers type 1 chain over type 2 acceptors, and type 1 tetrasaccharide is a better acceptor than type 1 disaccharide, suggesting a preference for a beta anomeric configuration of GlcNAc in the substrate. Individuals with active FUT3 are Lewis-positive (Le(+)), while those with inactive FUT3 are Lewis-negative (Le(-)).
FUT3 is also known as CD174, FT3B, FucT-III, LE, Les.
