title: Complexes with mixed primary and secondary cellulose synthases are functional in Arabidopsis plants.
abstract: In higher plants, cellulose is synthesized by so-called rosette protein complexes with cellulose synthases (CESAs) as catalytic subunits of the complex. The CESAs are divided into two distinct families, three of which are thought to be specialized for the primary cell wall and three for the secondary cell wall. In this article, the potential of primary and secondary CESAs forming a functional rosette complex has been investigated. The membrane-based yeast two-hybrid and biomolecular fluorescence systems were used to assess the interactions between three primary (CESA1, CESA3, CESA6), and three secondary (CESA4, CESA7, CESA8) Arabidopsis (Arabidopsis thaliana) CESAs. The results showed that all primary CESAs can physically interact both in vitro and in planta with all secondary CESAs. Although CESAs are broadly capable of interacting in pairwise combinations, they are not all able to form functional complexes in planta. Analysis of transgenic lines showed that CESA7 can partially rescue defects in the primary cell wall biosynthesis in a weak cesa3 mutant. Green fluorescent protein-CESA protein fusions revealed that when CESA3 was replaced by CESA7 in the primary rosette, the velocity of the mixed complexes was slightly faster than the native primary complexes. CESA1 in turn can partly rescue defects in secondary cell wall biosynthesis in a cesa8ko mutant, resulting in an increase of cellulose content relative to cesa8ko. These results demonstrate that sufficient parallels exist between the primary and secondary complexes for cross-functionality and open the possibility that mixed complexes of primary and secondary CESAs may occur at particular times.
authors.affiliation: Department of Biology, Stanford University, Stanford, California 94305, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Carroll
authors.forename: Nasim
authors.initials: N
authors.lastname: Mansoori
authors.forename: Shundai
authors.initials: S
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.forename: Samantha
authors.initials: S
authors.lastname: Vernhettes
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Chris
authors.initials: C
authors.lastname: Somerville
authors.forename: Ying
authors.initials: Y
authors.lastname: Gu
authors.forename: Luisa M
authors.initials: LM
authors.lastname: Trindade
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D046912:Multiprotein Complexes / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000502:physiology; D058526:Plant Vascular Bundle / Q000201:enzymology / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D025941:Protein Interaction Mapping / Q000379:methods; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D059467:Transcriptome; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C120025:IRX3 protein, Arabidopsis; D046912:Multiprotein Complexes; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002482:Cellulose; C516179:At5g05170 protein, Arabidopsis; C110227:CESA1 protein, Arabidopsis; C420969:CESA8 protein, Arabidopsis; D005964:Glucosyltransferases