Activation of Pollen Tube Callose Synthase by Detergents (Evidence for Different Mechanisms of Action)

Hj, Li; Bacic, Antony; Read, Stephen M.

doi:10.1104/pp.114.4.1255

Cited by 35 publications

(40 citation statements)

References 36 publications

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“…Activation of GS by detergents other than OG, e.g. Chaps, ZW 3-16 and lysophosphatidylcholine, has been reported for the enzyme from pollen tubes of N. alata [49]. However, this effect was shown on particulate enzyme preparations and not after detergent extraction of GS from microsomal fractions.…”

Section: Discussionmentioning

confidence: 70%

Biosynthesis of (1→3)‐β‐d‐glucan (callose) by detergent extracts of a microsomal fraction from Arabidopsis thaliana

Him

Pélosi

Chanzy

et al. 2001

European Journal of Biochemistry

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The aim of this work was to develop a biochemical approach to study (1 !3)-b-D-glucan (callose) biosynthesis using suspension cultures of Arabidopsis thaliana. Optimal conditions for in vitro synthesis of callose corresponded to an assay mixture containing 50 mM Mops buffer, pH 6.8, 1 mM UDP-glucose, 8 mM Ca 21 and 20 mM cellobiose. The enzyme was Ca 21 -dependent, and addition of Mg 21 to the reaction mixture did not favour cellulose biosynthesis. Enzyme kinetics suggested the existence of positive homotropic cooperativity of (1 !3)-b-D-glucan synthase for the substrate UDP-glucose, in agreement with the hypothesis that callose synthase consists of a multimeric complex containing several catalytic subunits. Detergents belonging to different families were tested for their ability to extract and preserve membrane-bound (1 !3)-b-D-glucan synthase activity. Cryo-transmission electron microscopy experiments showed that n-octyl-b-D-glucopyranoside allowed the production of micelle-like structures, whereas vesicles were obtained with Chaps and Zwittergent 3-12. The morphology and size of the (1 !3)-b-D-glucans synthesized in vitro by fractions obtained with different detergents were affected by the nature of the detergent tested. These data suggest that the general organization of the glucan synthase complexes and the properties of the in vitro products are influenced by the detergent used for protein extraction. The reaction products synthesized by different detergent extracts were characterized by infrared spectroscopy, methylation analysis, 13 C-NMR spectroscopy, electron microscopy and X-ray diffraction. These products were identified as linear (1 !3)-b-D-glucans having a degree of polymerization higher than 100, a microfibrillar structure, and a low degree of crystallinity.

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Section: Discussionmentioning

confidence: 70%

Biosynthesis of (1→3)‐β‐d‐glucan (callose) by detergent extracts of a microsomal fraction from Arabidopsis thaliana

Him

Pélosi

Chanzy

et al. 2001

European Journal of Biochemistry

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“…Overall, however, the observed general lack of induction of callose synthase genes (Table V) may indicate that callose synthase activity is regulated posttranscriptionally. Activity of callose synthase protein has been suggested to be regulated by G-proteins and Ca 21 (Schlü pmann et al, 1993;Li et al, 1997;Verma and Hong, 2001), so it is possible that the observed (b-D-Glc) 3 -induction of callose accumulation arises through posttranscriptional regulation.…”

Section: Cell Wall-related Genes With Expression Altered By (B-d-glc)mentioning

confidence: 99%

Binding of Arabinogalactan Proteins by Yariv Phenylglycoside Triggers Wound-Like Responses in Arabidopsis Cell Cultures

Nothnagel

2004

Plant Physiology

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Arabinogalactan-proteins (AGPs) are cell wall proteoglycans and are widely distributed in the plant kingdom. Classical AGPs and some nonclassical AGPs are predicted to have a glycosylphosphatidylinositol lipid anchor and have been suggested to be involved in cell-cell signaling. Yariv phenylglycoside is a synthetic probe that specifically binds to plant AGPs and has been used to study AGP functions. We treated Arabidopsis suspension cell cultures with Yariv phenylglycoside and observed decreased cell viability, increased cell wall apposition and cytoplasmic vesiculation, and induction of callose deposition. The induction of cell wall apposition and callose synthesis led us to hypothesize that Yariv binding of plant surface AGPs triggers wound-like responses. To study the effect of Yariv binding to plant surface AGPs and to further understand AGP functions, an Arabidopsis whole genome array was used to monitor the transcriptional modifications after Yariv treatment. By comparing the genes that are induced by Yariv treatment with genes whose expressions have been previously shown to be induced by other conditions, we conclude that the gene expression profile induced by Yariv phenylglycoside treatment is most similar to that of wound induction. It remains uncertain whether the Yariv phenylglycoside cross-linking of cell surface AGPs induces these genes through a specific AGP-based signaling mechanism or through a general mechanical perturbation of the cell surface.Arabinogalactan-proteins (AGPs) are widely distributed in plant species and are located at the plasma membrane and cell wall and in the media of cell cultures. These proteoglycans are typically composed of at least 90% carbohydrate by weight. The AGP core polypeptide is usually rich in Hyp, Ser, Thr, and Ala. Extended motifs comparable to those of extensins are not generally found in AGPs, although short stretches of Hyp alternating with Ala or Ser occur in many AGPs. The sugar moieties are composed of (1/3)-b-D-galactan backbones and (1/6)-b-D-galactan side chains with terminal sugars of Ara or GlcUA (Nothnagel, 1997). In the classical AGPs, the nascent polypeptide chain is synthesized with a C-terminal hydrophobic sequence that is later replaced with a glycosylphosphatidylinositol lipid anchor in the mature protein (Gaspar et al., 2001). The Arabidopsis genome contains approximately 47 genes encoding AGP core polypeptides (Schultz et al., 2002).The abundance of AGP genes and the high degree of posttranslational modifications of AGPs suggest a high genome investment in the synthesis of AGPs, which indicates that these macromolecules have conserved and important roles in plants. Although several possible roles of AGPs have been suggested (MajewskaSawka and Nothnagel, 2000), the detailed biological functions of AGPs currently remain unknown. Many experiments have demonstrated that the expression of AGPs is developmentally regulated in tissueand organ-specific manners (Majewska-Sawka and Nothnagel, 2000). Other experiments showed that AGPs are involved in s...

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“…Because there are no plant CalS antibodies available, we used a monoclonal antibody against GFP to follow the presence of GFPCalS1 chimeric protein in different fractions during purification. It is known that CalS activity is associated with the membranes and can be extracted effectively from the membrane fraction by a zwitterionic detergent, 3-([3-cholamidopropyl]dimethylammonio)-1-propanesulfonic acid (Chaps) (Lawson et al, 1989;Meikle et al, 1991;Li et al, 1997). The use of the product-entrapment technique resulted in a 70-to 90-fold increase in CalS specific activity (data not shown) over the crude membrane extract, and a highly enriched fraction of the CalS enzyme was obtained.…”

Section: Copurification Of Chimeric Gfp-cals1 Protein With the Cals Cmentioning

confidence: 99%

A Cell Plate–Specific Callose Synthase and Its Interaction with Phragmoplastin

2001

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Callose is synthesized on the forming cell plate and several other locations in the plant. We cloned an Arabidopsis cDNA encoding a callose synthase (CalS1) catalytic subunit. The CalS1 gene comprises 42 exons with 41 introns and is transcribed into a 6.0-kb mRNA. The deduced peptide, with an approximate molecular mass of 226 kD, showed sequence homology with the yeast 1,3-␤ -glucan synthases and is distinct from plant cellulose synthases. CalS1 contains 16 predicted transmembrane helices with the N-terminal region and a large central loop facing the cytoplasm. CalS1 interacts with two cell plate-associated proteins, phragmoplastin and a novel UDP-glucose transferase that copurifies with the CalS complex. That CalS1 is a cell plate-specific enzyme is demonstrated by the observations that the green fluorescent protein-CalS1 fusion protein was localized at the growing cell plate, that expression of CalS1 in transgenic tobacco cells enhanced callose synthesis on the forming cell plate, and that these cell lines exhibited higher levels of CalS activity. These data also suggest that plant CalS may form a complex with UDP-glucose transferase to facilitate the transfer of substrate for callose synthesis. INTRODUCTIONCallose was first detected almost 100 years ago on sieve plates of phloem elements, around pollen mother cells, in pollen grains, and in pollen tubes on the basis of its specific staining with aniline blue. The chemical structure of callose was characterized by Aspinall and Kessler (1957). It is a linear 1,3-␤ -glucan with some 1,6-branches and differs from cellulose, the major component of the plant cell wall. Callose has been localized at other locations as well, including the cell plate, plasmodesmata, root hair, cotton seed hair, and spiral thickenings in tracheids (Stone and Clarke, 1992). The synthesis of callose also can be induced by wounding, pathogen infection, and physiological stress (Stone and Clarke, 1992;Kauss, 1996). The deposition of callose at the cell plate precedes the synthesis of cellulose (Kakimoto and Shibaoka, 1992;Samuels et al., 1995). It is believed that callose deposition into the tubulovesicular network during cell plate formation may provide the spreading force that widens the tubules and converts the network into a fenestrated sheet (Samuels et al., 1995;Staehelin and Hepler, 1996).Attempts to purify callose synthase (CalS) from higher plants during the last two decades have generated variable data about the molecular mass and subunit composition of this enzyme. Partially purified CalS preparations have been shown to contain six to nine major polypeptides ranging in size from 25 to 92 kD (Kamat et al., 1992;Wasserman et al., 1992;Dhugga and Ray, 1994;McCormack et al., 1997). Using various affinity labeling techniques, it has been reported that the presumptive "catalytic subunit" of CalS from higher plants has a molecular mass of between 32 and 57 kD (Read and Delmer, 1987;Frost et al., 1990;Delmer et al., 1991;Li and Brown, 1993; Gibeaut and Carpita, 1994). Labeling techniqu...

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Activation of Pollen Tube Callose Synthase by Detergents (Evidence for Different Mechanisms of Action)

Cited by 35 publications

References 36 publications

Biosynthesis of (1→3)‐β‐d‐glucan (callose) by detergent extracts of a microsomal fraction from Arabidopsis thaliana

Biosynthesis of (1→3)‐β‐d‐glucan (callose) by detergent extracts of a microsomal fraction from Arabidopsis thaliana

Binding of Arabinogalactan Proteins by Yariv Phenylglycoside Triggers Wound-Like Responses in Arabidopsis Cell Cultures

A Cell Plate–Specific Callose Synthase and Its Interaction with Phragmoplastin

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