Cellulosic Microfibrils: Nascent Stages of Synthesis in a Higher Plant Cell

Mueller, Susette C.; Brown, R. Malcolm; Scott, Tom K.

doi:10.1126/science.194.4268.949

Cited by 89 publications

(39 citation statements)

References 14 publications

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“…Cellulose microfibrils are synthesized by a large membrane-bound protein complex. In the land plants and charophycean algae, the cellulose synthesis complex (CSC) has a "rosette" shape (Mueller et al, 1976;Mueller and Brown, 1980b;Kimura et al, 1999), and the entire CSC has reported diameters between 24 to 30 nm (Lerouxel et al, 2006). This structural information was revealed by freeze-fracture transmission electron microscopy, showing six lobes in a hexagonal arrangement at the point where the transmembrane helices of multiple cellulose synthase proteins (CESAs) cross the plasma membrane.…”

mentioning

confidence: 99%

A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers

et al. 2015

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A cellulose synthesis complex with a "rosette" shape is responsible for synthesis of cellulose chains and their assembly into microfibrils within the cell walls of land plants and their charophyte algal progenitors. The number of cellulose synthase proteins in this large multisubunit transmembrane protein complex and the number of cellulose chains in a microfibril have been debated for many years. This work reports a low resolution structure of the catalytic domain of CESA1 from Arabidopsis (Arabidopsis thaliana; AtCESA1CatD) determined by small-angle scattering techniques and provides the first experimental evidence for the self-assembly of CESA into a stable trimer in solution. The catalytic domain was overexpressed in Escherichia coli, and using a two-step procedure, it was possible to isolate monomeric and trimeric forms of AtCESA1CatD. The conformation of monomeric and trimeric AtCESA1CatD proteins were studied using small-angle neutron scattering and small-angle x-ray scattering. A series of AtCESA1CatD trimer computational models were compared with the small-angle x-ray scattering trimer profile to explore the possible arrangement of the monomers in the trimers. Several candidate trimers were identified with monomers oriented such that the newly synthesized cellulose chains project toward the cell membrane. In these models, the class-specific region is found at the periphery of the complex, and the plant-conserved region forms the base of the trimer. This study strongly supports the "hexamer of trimers" model for the rosette cellulose synthesis complex that synthesizes an 18-chain cellulose microfibril as its fundamental product.

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confidence: 99%

A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers

et al. 2015

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“…cell walls | CESA complexes | cell expansion | microtubules | polysaccharides C ellulose is synthesized at the plasma membrane by hexameric protein complexes with a diameter of 25-30 nm when observed by freeze-fracture electron microscopy in algae, moss, and vascular plants (1)(2)(3)(4). The only known component of the complexes is cellulose synthase (CESA), which is represented by 10 isoforms in Arabidopsis (5).…”

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confidence: 99%

Identification of a cellulose synthase-associated protein required for cellulose biosynthesis

Kaplinsky²,

Bringmann

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

234

242

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Cellulose synthase-interactive protein 1 (CSI1) was identified in a two-hybrid screen for proteins that interact with cellulose synthase (CESA) isoforms involved in primary plant cell wall synthesis. CSI1 encodes a 2,150-amino acid protein that contains 10 predicted Armadillo repeats and a C2 domain. Mutations in CSI1 cause defective cell elongation in hypocotyls and roots and reduce cellulose content. CSI1 is associated with CESA complexes, and csi1 mutants affect the distribution and movement of CESA complexes in the plasma membrane.

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“…This low density in vesiculated regions suggests that membrane surfaces had increased perhaps accompanied by lipid synthesis or the incorporation of lipid molecules which did not include the migration of intramembrane particles from the centre towards the vesiculated regions. Mueller et al (16). The following reasons strongly suggest that the hexagonal arrays of Micrasterias crux-melitensis are not artefacts but may be involved in the production of cell wall microfibrils.…”

Section: Discussionmentioning

confidence: 99%

“…However, these sections provide little information about the particles embedded in membranes. Recently, the structural relationship between cell wall microfibrils and plasma membrane particles has been pointed out using the freeze-fracture technique (10,14,16,18,19). In our study, intramembrane particles of dictyosomes, LVs and plasma membranes were examined by the freeze-fracture technique in order to gain further insight into cell wall synthesis and related questions.…”

Section: Micrasteriasmentioning

confidence: 99%

Membrane Structure of Dictyosomes, Large Vesicles and Plasma Membranes in a Green Alga, <I>Micrasterias crux-melitensis</I>

Noguchi

Tanaka

Ueda

1981

Cell Struct. Funct.

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ABSTRACT. Freeze-fracture replicas of the cisternal membranes of dictyosomes, large vesicle (LV) membranes and plasma membranes in the green alga, Micrasterias crux-melitensis, were examined by electron microscopy. Intramembrane particles were evenly distributed in the cisternal membranes in resting cells. In growing cells, the particle density decreased from the centre to the periphery of the cisternal membranes and was greatly diminished at the vesiculated parts. The particle density in LV membranes was about twenty percent that in cisternal membranes, but equivalent generally in the plasma membranes of growing daughter semicells. The possibility of the direct supply of LV membranes to the plasma membrane is discussed. In the plasma membranes of fully grown cells, rosette complexes with a hexagonal array were observed. Each rosette consisted of six particles. These complexes were assumed to correlate with microfibril formation in the cell wall.Dictyosomes show the conspicuous structural changes during cell growth in Micrasterias crux-melitensis (23). This structural change largely consists of the formation of large vesicles (LVs) at the margins of the dictyosomal cisternae. The LVs, in turn, may contribute to the formation of primary walls, adding their contents exocytotically to growing cell walls (22,24). Thus, the series of movements and transformations of dictyosomes and their derivative vesicles are closely related to cell wall synthesis. The behavior of dictyosomes and LVs during cell growth has been extensively studied by electron microscopy of thin sections (23). However, these sections provide little information about the particles embedded in membranes. Recently, the structural relationship between cell wall microfibrils and plasma membrane particles has been pointed out using the freeze-fracture technique (10,14,16,18,19). In our study, intramembrane particles of dictyosomes, LVs and plasma membranes were examined by the freeze-fracture technique in order to gain further insight into cell wall synthesis and related questions.

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Cellulosic Microfibrils: Nascent Stages of Synthesis in a Higher Plant Cell

Cited by 89 publications

References 14 publications

A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers

A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers

Identification of a cellulose synthase-associated protein required for cellulose biosynthesis

Membrane Structure of Dictyosomes, Large Vesicles and Plasma Membranes in a Green Alga, <I>Micrasterias crux-melitensis</I>

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