AUTHOR=Soto Maria J. , Prabhakar Pradeep Kumar , Wang Hsin-Tzu , Backe Jason , Chapla Digantkumar , Bartetzko Max , Black Ian M. , Azadi Parastoo , Peña Maria J. , Pfrengle Fabian , Moremen Kelley W. , Urbanowicz Breeanna R. , Hahn Michael G. 

TITLE=AtFUT4 and AtFUT6 Are Arabinofuranose-Specific Fucosyltransferases

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.589518

DOI=10.3389/fpls.2021.589518

ISSN=1664-462X

ABSTRACT=<p>The bulk of plant biomass is comprised of plant cell walls, which are complex polymeric networks, composed of diverse polysaccharides, proteins, polyphenolics, and hydroxyproline-rich glycoproteins (HRGPs). Glycosyltransferases (GTs) work together to synthesize the saccharide components of the plant cell wall. The <italic>Arabidopsis thaliana</italic> fucosyltransferases (FUTs), <italic>At</italic>FUT4, and <italic>At</italic>FUT6, are members of the plant-specific GT family 37 (GT37). <italic>At</italic>FUT4 and <italic>At</italic>FUT6 transfer fucose (Fuc) onto arabinose (Ara) residues of arabinogalactan (AG) proteins (AGPs) and have been postulated to be non-redundant AGP-specific FUTs. <italic>At</italic>FUT4 and <italic>At</italic>FUT6 were recombinantly expressed in mammalian HEK293 cells and purified for biochemical analysis. We report an updated understanding on the specificities of <italic>At</italic>FUT4 and <italic>At</italic>FUT6 that are involved in the synthesis of wall localized AGPs. Our findings suggest that they are selective enzymes that can utilize various arabinogalactan (AG)-like and non-AG-like oligosaccharide acceptors, and only require a free, terminal arabinofuranose. We also report with GUS promoter-reporter gene studies that <italic>AtFUT4</italic> and <italic>AtFUT6</italic> gene expression is sub-localized in different parts of developing <italic>A. thaliana</italic> roots.</p>