Fig. 1: Subcellular localization, catalytic activities, and biological relevance of human FUTs.
From: Structure, function, and implications of fucosyltransferases in health and disease
This figure illustrates the ER and Golgi compartments where fucosylation takes place. In the ER, the resident FUTs POFUT1, POFUT2, and POFUT3/4 catalyze the addition of Fuc to specific consensus motifs within certain domain structures: EGF-like domains, TSRs, and EMI domains, respectively. In the Golgi, FUTs mediate Fuc transfer with linkage specificity determined by enzyme subfamilies: FUT1 and FUT2 (α1,2-fucosylation) generate H-type epitopes; FUT3 and FUT5 (α1,3/4-fucosylation) produce various Lewis antigens including LeA, LeB, LeX, LeY, sLeA, and sLeX; FUT4, FUT6, FUT7, and FUT9 (α1,3-fucosylation) synthesize LeX, sLeX, and LeY; and FUT8 (α1,6-fucosylation) adds core Fuc to the chitobiose core of N-glycans. Symbols are used in accordance with the Symbol Nomenclature for Glycans (SNFG)293. The differential subcellular localization of FUTs, coupled with their stringent substrate specificity, constitutes a finely tuned regulatory system that minimizes enzymatic cross-reactivity. This spatial and functional compartmentalization enables precise modulation of the structure and function of fucosylated glycoconjugates across distinct cellular contexts. As a result, disruptions in the intracellular trafficking or localization of FUTs, despite preserved catalytic activity, can lead to aberrant glycosylation patterns with significant pathological consequences. Created in BioRender. Sanz Martínez, N. (2025) https://BioRender.com/pby9649.
