The cellulase KORRIGAN is part of the Cellulose Synthase Complex
Plant Physiol. 2014 Jun 19, pp.114.241216
Vain T, Crowell EF, Timpano H, Biot E, Desprez T, Mansoori N, Trindade LM, Pagant S, Robert S, Höfte H, Gonneau M, Vernhettes S

Plant growth and organ formation depend on the oriented deposition of load-bearing cellulose microfibrils in the cell wall. Cellulose is synthesized by a large molecular weight (MW) Cellulose Synthase Complex (CSC), which comprises at least three distinct cellulose synthases (CESAs). Cellulose synthesis in plants or bacteria also requires the activity of an endo-1,4-β-D-glucanase (EGase), the exact function of which in the synthesis process is not known. Here, we first show that a leaky mutation in the Arabidopsis thaliana membrane-bound EGase KORRIGAN1 (KOR1) not only caused reduced CSC movement in the plasma membrane but also a reduced cellulose synthesis inhibitor-induced accumulation of CSCs in intracellular compartments. This suggests a role for KOR1 both in the synthesis of cellulose microfibrils and in the intracellular trafficking of CSCs. Next, we used a multidisciplinary approach including live cell imaging, gel filtration chromatography analysis, split ubiquitin assays in yeast and -bimolecular fluorescence complementation to show that, in contrast to previous observations, KOR1 is an integral part of the primary cell wall cellulose synthase complex in the plasma membrane.
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