title: Multiple N-glycans cooperate in the subcellular targeting and functioning of Arabidopsis KORRIGAN1.
abstract: Arabidopsis thaliana KORRIGAN1 (KOR1) is an integral membrane endo-β1,4-glucanase in the trans-Golgi network and plasma membrane that is essential for cellulose biosynthesis. The extracellular domain of KOR1 contains eight N-glycosylation sites, N1 to N8, of which only N3 to N7 are highly conserved. Genetic evidence indicated that cellular defects in attachment and maturation of these N-glycans affect KOR1 function in vivo, whereas the manner by which N-glycans modulate KOR1 function remained obscure. Site-directed mutagenesis analysis of green fluorescent protein (GFP)-KOR1 expressed from its native regulatory sequences established that all eight N-glycosylation sites (N1 to N8) are used in the wild type, whereas stt3a-2 cells could only inefficiently add N-glycans to less conserved sites. GFP-KOR1 variants with a single N-glycan at nonconserved sites were less effective than those with one at a highly conserved site in rescuing the root growth phenotype of rsw2-1 (kor1 allele). When functionally compromised, GFP-KOR1 tended to accumulate at the tonoplast. GFP-KOR1Δall (without any N-glycan) exhibited partial complementation of rsw2-1; however, root growth of this line was still negatively affected by the absence of complex-type N-glycan modifications in the host plants. These results suggest that one or several additional factor(s) carrying complex N-glycans cooperate(s) with KOR1 in trans to grant proper targeting/functioning in plant cells.
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rips
authors.affiliation: Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133.
authors.forename: Nolan
authors.initials: N
authors.lastname: Bentley
authors.affiliation: Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133.
authors.forename: In Sil
authors.initials: IS
authors.lastname: Jeong
authors.affiliation: Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133.
authors.forename: Justin L
authors.initials: JL
authors.lastname: Welch
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: von Schaewen
authors.affiliation: Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Molecular and Environmental Plant Science Program, Texas A&M University, College Station, Texas 77843-2133 koiwa@tamu.edu.
authors.forename: Hisashi
authors.identifier: http://orcid.org/0000-0002-7421-340X
authors.initials: H
authors.lastname: Koiwa
mesh_terms: D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000201:enzymology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism*; D017124:Conserved Sequence; D004843:Epistasis, Genetic; D017930:Genes, Reporter; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006602:Hexosyltransferases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D011134:Polysaccharides / Q000378:metabolism*; D021381:Protein Transport; D011523:Protoplasts / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C429844:KOR1 protein, Arabidopsis; D008565:Membrane Proteins; D011134:Polysaccharides; D049452:Green Fluorescent Proteins; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase; D002480:Cellulase