Arabidopsis thaliana KORRIGAN1 protein: N-glycan modification, localization, and function in cellulose biosynthesis and osmotic stress responses [Arabidopsis thaliana KORRIGAN1 Protein: N-Glykan-Modification, Lokalisierung, und Funktion für die Zellulose-Biosynthese und osmotische Stress-Antworten]

von Schaewen, A; Rips, S; Jeong, IS; Koiwa, H

Abstract

Plant cellulose biosynthesis is a complex process involving cellulose-synthase complexes (CSCs) and various auxiliaryfactors essential for proper orientation and crystallinity of cellulose microfibrils in the apoplast. Among them isKORRIGAN1 (KOR1), a type-II membrane protein with multiple N-glycans within its C-terminal cellulase domain.N-glycosylation of the cellulase domain was important for KOR1 targeting to and retention within the trans-Golginetwork (TGN), and prevented accumulation of KOR1 at tonoplasts. The degree of successful TGN localization of KOR1agreed well with in vivo-complementation efficacy of the mutant, suggesting non-catalytic functions in the TGN.A dynamic interaction network involving microtubules, CSCs, KOR1, and currently unidentified glycoproteincomponent(s) likely determines stress-triggered re-organization of cellulose biosynthesis and resumption of cell-wallgrowth under stress.