A chloroplast processing enzyme functions as the general stromal processing peptidase

Richter, Stefan; Lamppa, Gayle K.

doi:10.1073/pnas.95.13.7463

Cited by 176 publications

(135 citation statements)

References 49 publications

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“…The transit peptide consensus motif of (Val/Ile)-X-(Ala/Cys)2Ala that was described by Gavel and von Heijne (1990) and detected in the LAP-A proteins (Gu et al, 1996a) was not detected in the N-terminal region of LAP-N. Richter and Lamppa (1998) showed that the stromal endopeptidase that processes plant transit peptides primarily cleaves between Arg/Lys and Ala residues; this motif was not detected in LAP-A or LAP-N, although there was an abundance of basic residues in these proteins between residues 45 and 49 (Fig. 6).…”

Section: Rnas and Proteinsmentioning

confidence: 99%

Isolation and Characterization of the Neutral Leucine Aminopeptidase (LapN) of Tomato

Park

Walling

2003

Plant Physiology

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Tomatoes (Lycopersicon esculentum) express two forms of leucine aminopeptidase (LAP-A and LAP-N) and two LAP-like proteins. The relatedness of LAP-N and LAP-A was determined using affinity-purified antibodies to four LAP-A protein domains. Antibodies to epitopes in the most N-terminal region were able to discriminate between LAP-A and LAP-N, whereas antibodies recognizing central and COOH-terminal regions recognized both LAP polypeptides. Two-dimensional immunoblots showed that LAP-N and the LAP-like proteins were detected in all vegetative (leaves, stems, roots, and cotyledons) and reproductive (pistils, sepals, petals, stamens, and floral buds) organs examined, whereas LAP-A exhibited a distinct expression program. LapN was a single-copy gene encoding a rare-class transcript. A full-length LapN cDNA clone was isolated, and the deduced sequence had 77% peptide sequence identity with the wound-induced LAP-A. Leucyl aminopeptidases (LAPs; EC 3.4.11.1) are members of the M17 family of peptidases (Barrett et al., 1998). LAPs are ubiquitous being found in animals, plants, and prokaryotic cells. These hexameric metallopeptidases catalyze the release of the N-terminal residues from protein, peptide, fluorometric, and chromogenic substrates. The best characterized LAPs are from Bos taurus, Escherichia coli and tomato (Lycopersicon esculentum). X-ray crystal structures of the bovine and E. coli LAPs have provided insight into the LAP catalytic mechanism (Kim and Lipscomb, 1994;Sträter and Lipscomb, 1995;Sträter et al., 1999a). The roles of selected residues of the E. coli and tomato LAPs in chromogenic or peptide substrate catalysis, respectively, have been tested by site-directed mutagenesis (Sträter et al., 1999b;Gu and Walling, 2002).In most plants, three classes of LAP-related polypeptides are detected using a tomato LAP antiserum, including the 66-and 77-kD LAP-like proteins and the 55-kD neutral LAP (LAP-N; Chao et al., 2000). Only in a subset of the Solanaceae is a second 55-kD LAP species (LAP-A) detected (Hildmann et al., 1992;Gu et al., 1996b;Chao et al., 2000). In tomato, LAP-A protomers have an acidic pI and are encoded by two genes (LapA1 and LapA2), which are expressed during floral and fruit development. The LapA genes are not expressed in foliage from healthy plants (Chao et al., 1999). However, LapA RNAs, proteins, and activities accumulate locally and systemically in leaves after wounding, Pseudomonas syringae pv. tomato and Phytophthora parasitica infection, and caterpillar feeding (Pautot et al., 1993(Pautot et al., , 2001Gu et al., 1996b;Chao et al., 1999;Jwa and Walling, 2001). The activation of LapA gene expression by jasmonic acid (JA), abscisic acid, the phytotoxin coronatine (a JA mimic), and suppression of LapA by salicylic acid is consistent with the regulation of the tomato LapA genes by the wound octadecanoid pathway (Chao et al., 1999). LapA genes also respond to signals generated during water deficit and salinity stress (Chao et al., 1999). The potato (Solanum tuberosum) Lap RNAs also ac...

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Section: Rnas and Proteinsmentioning

confidence: 99%

Isolation and Characterization of the Neutral Leucine Aminopeptidase (LapN) of Tomato

Park

Walling

2003

Plant Physiology

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“…Testing newly identified proteins by both programs is probably the best option at the moment to get additional support/confirmation for chloroplast localization. It has been noted that in many cases, an additional amino acid residue needs to be removed to obtain the mature protein sequence (Richter and Lamppa, 1998;Emanuelsson et al, 1999).…”

Section: Consensus Sequences and Prediction Of Localization And Cleavmentioning

confidence: 99%

Proteomics of the Chloroplast: Systematic Identification and Targeting Analysis of Lumenal and Peripheral Thylakoid Proteins

Peltier

Friso

Kalume³

et al. 2000

Plant Cell

336

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The soluble and peripheral proteins in the thylakoids of pea were systematically analyzed by using two-dimensional electrophoresis, mass spectrometry, and N-terminal Edman sequencing, followed by database searching. After correcting to eliminate possible isoforms and post-translational modifications, we estimated that there are at least 200 to 230 different lumenal and peripheral proteins. Sixty-one proteins were identified; for 33 of these proteins, a clear function or functional domain could be identified, whereas for 10 proteins, no function could be assigned. For 18 proteins, no expressed sequence tag or full-length gene could be identified in the databases, despite experimental determination of a significant amount of amino acid sequence. Nine previously unidentified proteins with lumenal transit peptides are presented along with their full-length genes; seven of these proteins possess the twin arginine motif that is characteristic for substrates of the TAT pathway. Logoplots were used to provide a detailed analysis of the lumenal targeting signals, and all nuclear-encoded proteins identified on the two-dimensional gels were used to test predictions for chloroplast localization and transit peptides made by the software programs ChloroP, PSORT, and SignalP. A combination of these three programs was found to provide a useful tool for evaluating chloroplast localization and transit peptides and also could reveal possible alternative processing sites and dual targeting. The potential of proteomics for plant biology and homology-based searching with mass spectrometry data is discussed.

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“…The plastid contains several proteases including stromal ClpP (Olinares et al, 2011), stromal and thylakoid Deg (Schuhmann and Adamska, 2012), thylakoid FtsH (Adam et al, 2001;Sokolenko et al, 2002;Peltier et al, 2004), the intramembrane rhomboid proteases (Adam, 2013), and the thylakoid-bound SppA (Lensch et al, 2001) and Egy1 proteases (Chen et al, 2005). Moreover, several processing proteases exist in these organelles, such as SPP (stromal processing peptidase) and TPP (thylakoid processing protease), which are required for cleaving the transit peptide and the thylakoid targeting domain, respectively (Oelmüller et al, 1996;Richter and Lamppa, 1998). Among these proteases, only the ClpP1 subunit is encoded by the chloroplast genome.…”

Section: Introductionmentioning

confidence: 99%

Conditional Depletion of the Chlamydomonas Chloroplast ClpP Protease Activates Nuclear Genes Involved in Autophagy and Plastid Protein Quality Control

et al. 2014

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Plastid protein homeostasis is critical during chloroplast biogenesis and responses to changes in environmental conditions. Proteases and molecular chaperones involved in plastid protein quality control are encoded by the nucleus except for the catalytic subunit of ClpP, an evolutionarily conserved serine protease. Unlike its Escherichia coli ortholog, this chloroplast protease is essential for cell viability. To study its function, we used a recently developed system of repressible chloroplast gene expression in the alga Chlamydomonas reinhardtii. Using this repressible system, we have shown that a selective gradual depletion of ClpP leads to alteration of chloroplast morphology, causes formation of vesicles, and induces extensive cytoplasmic vacuolization that is reminiscent of autophagy. Analysis of the transcriptome and proteome during ClpP depletion revealed a set of proteins that are more abundant at the protein level, but not at the RNA level. These proteins may comprise some of the ClpP substrates. Moreover, the specific increase in accumulation, both at the RNA and protein level, of small heat shock proteins, chaperones, proteases, and proteins involved in thylakoid maintenance upon perturbation of plastid protein homeostasis suggests the existence of a chloroplast-to-nucleus signaling pathway involved in organelle quality control. We suggest that this represents a chloroplast unfolded protein response that is conceptually similar to that observed in the endoplasmic reticulum and in mitochondria.

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A chloroplast processing enzyme functions as the general stromal processing peptidase

Cited by 176 publications

References 49 publications

Isolation and Characterization of the Neutral Leucine Aminopeptidase (LapN) of Tomato

Isolation and Characterization of the Neutral Leucine Aminopeptidase (LapN) of Tomato

Proteomics of the Chloroplast: Systematic Identification and Targeting Analysis of Lumenal and Peripheral Thylakoid Proteins

Conditional Depletion of the Chlamydomonas Chloroplast ClpP Protease Activates Nuclear Genes Involved in Autophagy and Plastid Protein Quality Control

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