Publication Information
Ebert et al., 2018
Abstract
Nat Plants. 2018 Oct;4(10):792-801. doi: 10.1038/s41477-018-0235-5. Epub 2018
Sep 17.
A Golgi UDP-GlcNAc transporter delivers substrates for N-linked glycans and
sphingolipids.
Ebert B(1), Rautengarten C(1), McFarlane HE(1), Rupasinghe T(2), Zeng W(1)(3),
Ford K(1)(3), Scheller HV(4)(5), Bacic A(1)(3), Roessner U(2), Persson S(1),
Heazlewood JL(6).
Author information:
(1)School of Biosciences, University of Melbourne, Melbourne, Victoria,
Australia.
(2)Metabolomics Australia, School of Biosciences, University of Melbourne,
Melbourne, Victoria, Australia.
(3)ARC Centre of Excellence in Plant Cell Walls, School of Biosciences,
University of Melbourne, Melbourne, Victoria, Australia.
(4)Joint BioEnergy Institute and Environmental Genomics and Systems Biology
Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
(5)Department of Plant and Microbial Biology, University of California,
Berkeley, CA, USA.
(6)School of Biosciences, University of Melbourne, Melbourne, Victoria,
Australia. jheazlewood@unimelb.edu.au.
Glycosylation requires activated glycosyl donors in the form of nucleotide
sugars to drive processes such as post-translational protein modifications and
glycolipid and polysaccharide biosynthesis. Most of these reactions occur in the
Golgi, requiring cytosolic-derived nucleotide sugars, which need to be actively
transferred into the Golgi lumen by nucleotide sugar transporters. We identified
a Golgi-localized nucleotide sugar transporter from Arabidopsis thaliana with
affinity for UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) and assigned it UDP-GlcNAc
transporter 1 (UGNT1). Profiles of N-glycopeptides revealed that plants carrying
the ugnt1 loss-of-function allele are virtually devoid of complex and hybrid
N-glycans. Instead, the N-glycopeptide population from these alleles exhibited
high-mannose structures, representing structures prior to the addition of the
first GlcNAc in the Golgi. Concomitantly, sphingolipid profiling revealed that
the biosynthesis of GlcNAc-containing glycosyl inositol phosphorylceramides
(GIPCs) is also reliant on this transporter. By contrast, plants carrying the
loss-of-function alleles affecting ROCK1, which has been reported to transport
UDP-GlcNAc and UDP-N-acetylgalactosamine, exhibit no changes in N-glycan or GIPC
profiles. Our findings reveal that plants contain a single UDP-GlcNAc
transporter that delivers an essential substrate for the maturation of N-glycans
and the GIPC class of sphingolipids.
DOI: 10.1038/s41477-018-0235-5
PMID: 30224661 [Indexed for MEDLINE]
