Evidence for Autocatalytic Cross-Linking of Hydroxyproline-Rich Glycoproteins during Extracellular Matrix Assembly in Volvox

Ender, Frank; Godl, Klaus; Wenzl, Stephan; Sumper, Manfred

doi:10.1105/tpc.000711

Cited by 50 publications

(56 citation statements)

References 41 publications

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“…As shown by Ender et al (2002), two main Hyp-rich components (pherophorins DZ1 and DZ2) of the extracellular matrix of Volvox carteri are able to self-assemble and cross-link in an apparently autocatalytic reaction. Cross-linking of pherophorin DZ1 occurs via carbohydrate side chains by the formation of Ara-5Ј-phospho-5Ј-Ara phosphodiester bonds (Ender et al, 2002), as described previously for the extracellular matrix glycoproteins SSG 185 and pherophorin S (Holst et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

“…Cross-linking of pherophorin DZ1 occurs via carbohydrate side chains by the formation of Ara-5Ј-phospho-5Ј-Ara phosphodiester bonds (Ender et al, 2002), as described previously for the extracellular matrix glycoproteins SSG 185 and pherophorin S (Holst et al, 1989). To date, such a cross-linking mechanism has not been described for the cell wall glycoproteins of Chlamydomonas, although polypeptides were found to be released from the highly purified insoluble glycoprotein framework of this volvocine green alga during chemical deglycosylation by anhydrous HF/pyridine (Vogeler et al, 1990;Voigt et al, 1996; this report).…”

Section: Discussionmentioning

confidence: 99%

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14-3-3 Proteins Are Constituents of the Insoluble Glycoprotein Framework of the Chlamydomonas Cell Wall

Voigt

Frank

2003

Plant Cell

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The cell wall of the unicellular green alga Chlamydomonas reinhardtii consists predominantly of Hyp-rich glycoproteins, which also occur in the extracellular matrix of multicellular green algae and higher plants. In addition to the Hyp-rich polypeptides, the insoluble glycoprotein framework of the Chlamydomonas cell wall contains minor amounts of 14-3-3 proteins, as revealed by immunochemical studies and mass spectroscopic analysis of tryptic peptides. Polypeptides immunologically related to the 14-3-3 proteins also were found in the culture medium of Chlamydomonas. The levels of two of these 14-3-3-related polypeptides were decreased in the culture medium of the wall-deficient mutant cw-15 . These findings indicate that 14-3-3 proteins are involved in the cross-linking of Hyp-rich glycoproteins in the Chlamydomonas cell wall.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

14-3-3 Proteins Are Constituents of the Insoluble Glycoprotein Framework of the Chlamydomonas Cell Wall

Voigt

Frank

2003

Plant Cell

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“…Whereas many chimeric HRGPs in algae and higher plants resemble the agglutinins and Gp1 in having a single long P-rich sequence interconnecting, and perhaps penetrating, globular N-terminal and/or C-terminal domains (Baldwin et al, 1992;Ertl et al, 1992;Rubinstein et al, 1995;Woessner and Goodenough, 1989;Waffenschmidt et al, 1993;Wu et al, 1993;Woessner et al, 1994;Godl et al, 1997;Schultz et al, 1997;Ender et al, 1999Ender et al, , 2002Rodriguez et al, 1999;Bosch et al, 2001;Hallmann et al, 2001), other chimeric HRGPs have short P-rich segments that would at best form very short shafts (L. Song and W.L. Dentler, unpublished data, GenBank AF508983; Sumper and Hallmann, 1998;R.A.…”

Section: Organization Of Chimeric Hrgpsmentioning

confidence: 99%

PlusandMinusSexual Agglutinins fromChlamydomonas reinhardtii

et al. 2005

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Gametes of the unicellular green alga Chlamydomonas reinhardtii undergo sexual adhesion via enormous chimeric Hyp-rich glycoproteins (HRGPs), the plus and minus sexual agglutinins, that are displayed on their flagellar membrane surfaces. We have previously purified the agglutinins and analyzed their structural organization using electron microscopy. We report here the cloning and sequencing of the Sag1 and Sad1 genes that encode the two agglutinins and relate their derived amino acid sequences and predicted secondary structure to the morphology of the purified proteins. Both agglutinin proteins are organized into three distinct domains: a head, a shaft in a polyproline II configuration, and an N-terminal domain. The plus and minus heads are related in overall organization but poorly conserved in sequence except for two regions of predicted hydrophobic a-helix. The shafts contain numerous repeats of the PPSPX motif previously identified in Gp1, a cell wall HRGP. We propose that the head domains engage in autolectin associations with the distal termini of their own shafts and suggest ways that adhesion may involve head-head interactions, exolectin interactions between the heads and shafts of opposite type, and antiparallel shaft-shaft interactions mediated by carbohydrates displayed in polyproline II configurations.

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“…Although cross-linking of extracellular HRGPs in Volvox carteri appears to be autocatalytic (18), the formation of the extensin network in higher plants requires peroxide and peroxidase (1). Class III peroxidases can oxidize a variety of physiological substrates and, in general, demonstrate little substrate specificity, making it difficult to attribute a specific function to individual peroxidases in vivo.…”

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confidence: 99%

A Biochemical and Molecular Characterization of LEP1, an Extensin Peroxidase from Lupin

Price

Pinheiro

Soares

et al. 2003

Journal of Biological Chemistry

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An analysis of apoplastic extensin cross-linking activity in vegetative organs of Lupinus albus indicated that leaves contained the highest specific activity. Assays of peroxidases fractionated from this material demonstrated that this activity could be largely attributed to a soluble and apoplastic 51-kDa peroxidase, denoted LEP1. Relative to other purified peroxidases, LEP1 demonstrates high extensin cross-linking activity and can be classified as an extensin peroxidase (EP). Optimal conditions for the in vitro oxidation of other phenolic substrates included 1.5-3.0 mM peroxide at pH 5.0. EP activity of LEP1 was low under these conditions but optimal and substantially higher with 100 M peroxide and neutral pH, suggesting that physiological changes in pH and peroxide in muro could heavily influence the extensin cross-linking activity of LEP1 in vivo. Analysis of LEP1 glycans indicated 11-12 N-linked glycans, predominantly the heptasaccharide Man 3 XylFucGlcNAc 2 , but also larger structures showing substantial heterogeneity. Comparative assays with horseradish peroxidase isoform C and peanut peroxidases suggested the high level of glycosylation in LEP1 may be responsible for the high solubility of this EP in the apoplastic space. A fulllength cDNA corresponding to LEP1 was cloned. Quantitative reverse transcriptase-PCR demonstrated LEP1 induction in apical portions of etiolated hypocotyls 30 -60 min after exposure to white light, prior to the onset of growth inhibition. Comparative modeling of the translated sequence indicated an unusually unobstructed equatorial cleft across the substrate access channel, which might facilitate interaction with extensin and confer higher EP activity.

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Evidence for Autocatalytic Cross-Linking of Hydroxyproline-Rich Glycoproteins during Extracellular Matrix Assembly in Volvox

Cited by 50 publications

References 41 publications

14-3-3 Proteins Are Constituents of the Insoluble Glycoprotein Framework of the Chlamydomonas Cell Wall

14-3-3 Proteins Are Constituents of the Insoluble Glycoprotein Framework of the Chlamydomonas Cell Wall

PlusandMinusSexual Agglutinins fromChlamydomonas reinhardtii

A Biochemical and Molecular Characterization of LEP1, an Extensin Peroxidase from Lupin

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