The Photorespiratory Pathway of Leaf Peroxisomes

Reumann, Sigrun

doi:10.1007/978-94-015-9858-3_5

Cited by 17 publications

(20 citation statements)

References 228 publications

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“…The genes that were cloned from Arabidopsis were supplemented by the Arabidopsis orthologs of known PTS1/2-targeted matrix proteins, which were identified by sequence similarity. In case of unusually large gene families in Arabidopsis, such as that of the glycolate oxidase (GOX)-related proteins comprising five genes (Reumann, 2002), the orthologs corresponding to the reported proteins were identified according to maximum sequence similarity and similar tissuespecific expression pattern deduced from a ''digital northern'' (Mekhedov et al, 2000; data not shown). In a digital northern a maximum number of ESTs corresponding to the gene of interest are retrieved from all publicly accessible EST collections of the same plant species and analyzed semiquantitatively for the source from which the RNA was isolated (e.g.…”

Section: Identification Of Sequences Homologous To Pts1-and Pts2-targmentioning

confidence: 99%

“…; Schwartz et al, 1991) was excluded. In case of unusually large novel gene families in Arabidopsis, such as that of the GOX homologs comprising five genes (Reumann 2002), the Arabidopsis homolog(s) corresponding to the reported proteins were identified according to maximum sequence similarity and similar expression pattern deduced from a digital northern (Mekhedov et al, 2000; e.g. GOX1/2, At3g14415/20).…”

Section: Selection Of the Arabidopsis Proteins Suitable For The Bioinmentioning

confidence: 99%

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Specification of the Peroxisome Targeting Signals Type 1 and Type 2 of Plant Peroxisomes by Bioinformatics Analyses

2004

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To specify the C-terminal peroxisome targeting signal type 1 (PTS1) and the N-terminal PTS2 for higher plants, a maximum number of plant cDNAs and expressed sequence tags that are homologous to PTS1-and PTS2-targeted plant proteins was retrieved from the public databases and the primary structure of their targeting domains was analyzed for conserved properties. According to their high overall frequency in the homologs and their widespread occurence in different orthologous groups, nine major PTS1 tripeptides ([SA][RK] [LM]. without AKM. plus SRI. and PRL.) and two major PTS2 nonapeptides (R[LI]x 5 HL) were defined that are considered good indicators for peroxisomal localization if present in unknown proteins. A lower but significant number of homologs contained 1 of 11 minor PTS1 tripeptides or of 9 minor PTS2 nonapeptides, many of which have not been identified before in plant peroxisomal proteins. The region adjacent to the PTS peptides was characterized by specific conserved properties as well, such as a pronounced incidence of basic and Pro residues and a high positive net charge, which probably play an auxiliary role in peroxisomal targeting. By contrast, several peptides with assumed peroxisomal targeting properties were not found in any of the 550 homologs and hence play-if at all-only a minor role in peroxisomal targeting. Based on the definition of these major and minor PTS and on the recognition of additional conserved properties, the accuracy of predicting peroxisomal proteins can be raised and plant genomes can be screened for novel proteins of peroxisomes more successfully.

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Section: Identification Of Sequences Homologous To Pts1-and Pts2-targmentioning

confidence: 99%

Section: Selection Of the Arabidopsis Proteins Suitable For The Bioinmentioning

confidence: 99%

Specification of the Peroxisome Targeting Signals Type 1 and Type 2 of Plant Peroxisomes by Bioinformatics Analyses

2004

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“…Plant peroxisomes differentiate into tissue-and developmental-specific variants, such as leaf peroxisomes in mature leaves and glyoxysomes in germinating seeds, and typically participate in metabolic pathways and networks that are spread over multiple subcellular compartments. For instance, the recycling of 2-phosphoglycolate during photorespiration requires orchestration of 15 chloroplastic, peroxisomal, and mitochondrial enzymes and numerous transport proteins to transfer the intermediates between cell compartments (for review, see Reumann, 2002;Reumann and Weber, 2006). Similarly, fatty acids are released from lipid bodies during seed germination and transferred to glyoxysomes, where the carbon chain is transformed into sucrose in coordination with mitochondrial and cytosolic enzymes.…”

Section: Introductionmentioning

confidence: 99%

Proteome Analysis ofArabidopsisLeaf Peroxisomes Reveals Novel Targeting Peptides, Metabolic Pathways, and Defense Mechanisms

et al. 2007

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We have established a protocol for the isolation of highly purified peroxisomes from mature Arabidopsis thaliana leaves and analyzed the proteome by complementary gel-based and gel-free approaches. Seventy-eight nonredundant proteins were identified, of which 42 novel proteins had previously not been associated with plant peroxisomes. Seventeen novel proteins carried predicted peroxisomal targeting signals (PTS) type 1 or type 2; 11 proteins contained PTS-related peptides. Peroxisome targeting was supported for many novel proteins by in silico analyses and confirmed for 11 representative fulllength fusion proteins by fluorescence microscopy. The targeting function of predicted and unpredicted signals was investigated and SSL>, SSI>, and ASL> were established as novel functional PTS1 peptides. In contrast with the generally accepted confinement of PTS2 peptides to the N-terminal domain, the bifunctional transthyretin-like protein was demonstrated to carry internally a functional PTS2. The novel enzymes include numerous enoyl-CoA hydratases, short-chain dehydrogenases, and several enzymes involved in NADP and glutathione metabolism. Seven proteins, including b-glucosidases and myrosinases, support the currently emerging evidence for an important role of leaf peroxisomes in defense against pathogens and herbivores. The data provide new insights into the biology of plant peroxisomes and improve the prediction accuracy of peroxisome-targeted proteins from genome sequences.

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“…Although peroxisomes are best known for their roles in fatty acid b-oxidation and hydrogen peroxide metabolism, peroxisomes are ubiquitous organelles implicated in diverse cellular and developmental processes (Hayashi and Nishimura, 2003;Titorenko and Rachubinski, 2004). Approximately 280 Arabidopsis thaliana proteins are predicted to be targeted to the peroxisome matrix (Reumann et al, 2004); some of these act in photorespiration (Reumann, 2002), embryonic development (Lin et al, 1999;Hu et al, 2002;Schumann et al, 2003;Sparkes et al, 2003;Woodward and Bartel, 2005a), photomorphogenesis (Hu et al, 2002), and hormone metabolism, including jasmonic acid biosynthesis (Weber, 2002) and conversion of the protoauxin indole-3-butyric acid (IBA) into active indole-3-acetic acid (IAA) Woodward and Bartel, 2005b).…”

Section: Introductionmentioning

confidence: 99%

Identification and Functional Characterization ofArabidopsisPEROXIN4 and the Interacting Protein PEROXIN22[W]

et al. 2005

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Peroxins are genetically defined as proteins necessary for peroxisome biogenesis. By screening for reduced response to indole-3-butyric acid, which is metabolized to active auxin in peroxisomes, we isolated an Arabidopsis thaliana peroxin4 (pex4) mutant. This mutant displays sucrose-dependent seedling development and reduced lateral root production, characteristics of plant peroxisome malfunction. We used yeast two-hybrid analysis to determine that PEX4, an apparent ubiquitin-conjugating enzyme, interacts with a previously unidentified Arabidopsis protein, PEX22. A pex4 pex22 double mutant enhanced pex4 defects, confirming that PEX22 is a peroxin. Expression of both Arabidopsis genes together complemented yeast pex4 or pex22 mutant defects, whereas expression of either gene individually failed to rescue the corresponding yeast mutant. Therefore, it is likely that the Arabidopsis proteins can function similarly to the yeast PEX4–PEX22 complex, with PEX4 ubiquitinating substrates and PEX22 tethering PEX4 to the peroxisome. However, the severe sucrose dependence of the pex4 pex22 mutant is not accompanied by correspondingly strong defects in peroxisomal matrix protein import, suggesting that this peroxin pair may have novel plant targets in addition to those important in fungi. Isocitrate lyase is stabilized in pex4 pex22, indicating that PEX4 and PEX22 may be important during the remodeling of peroxisome matrix contents as glyoxysomes transition to leaf peroxisomes.

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The Photorespiratory Pathway of Leaf Peroxisomes

Cited by 17 publications

References 228 publications

Specification of the Peroxisome Targeting Signals Type 1 and Type 2 of Plant Peroxisomes by Bioinformatics Analyses

Specification of the Peroxisome Targeting Signals Type 1 and Type 2 of Plant Peroxisomes by Bioinformatics Analyses

Proteome Analysis ofArabidopsisLeaf Peroxisomes Reveals Novel Targeting Peptides, Metabolic Pathways, and Defense Mechanisms

Identification and Functional Characterization ofArabidopsisPEROXIN4 and the Interacting Protein PEROXIN22[W]

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