Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in protein kinase activity have been investigated during the early response of suspension cultured cells of French bean to fungal elicitor. One of the kinases activated has a known target, phenylalanine ammonia-lyase (PAL), which has an important role in plant defence responses, and was purified. Kinase acivity during purification was monitored for both the PAL-derived peptide and syntide-2, which it also phosphorylated. The kinase had an Mr of 55,000 on the basis of gel migration, 45Ca2+ binding, autophosphorylation and phosphorylation of various substrates using in-gel assays. The kinase has been characterised with respect to kinetics and other properties in vitro and appears to be a CDPK. In-gel assays were also used to show that this kinase and a number of other CDPKs of similar Mr showed complex changes in elicitor-treated suspension-cultured cells of French bean. An activation was observed within 10 min and was maintained for up to 4 h. The time course of activation was different from MAP kinase and casein kinase assayed in the same extracts. However, at 5 min after addition of elicitor there is a transient inactivation of the CDPKs before activation. This inactivation can be mimicked by adding forskolin to the cells 30 min before elicitation, which brings about changes in the cellular pH. Forskolin potentiates the oxidative burst when elicitor is subsequently added while the CDPK cannot be activated by elicitor upon forskolin treatment. In contrast, intracellular acidification brought about by forskolin brings about slight activation of MAPkinase.
Plant Mol Biol 2002 Jul
PMID:Regulation of CDPKs, including identification of PAL kinase, in biotically stressed cells of French bean. 1209 Jun 28

Sulfated fucans are common structural components of the cell walls of marine brown algae. Using a fucan-degrading hydrolase isolated from a marine bacterium, we prepared sulfated fucan oligosaccharides made of mono- and disulfated fucose units alternatively bound by alpha-1,4 and alpha-1,3 glycosidic linkages, respectively. Here, we report on the elicitor activity of such fucan oligosaccharide preparations in tobacco. In suspension cell cultures, oligofucans at the dose of 200 microg ml(-1) rapidly induced a marked alkalinization of the extracellular medium and the release of hydrogen peroxide. This was followed within a few hours by a strong stimulation of phenylalanine ammonia-lyase and lipoxygenase activities. Tobacco leaves treated with oligofucans locally accumulated salicylic acid (SA) and the phytoalexin scopoletin and expressed several pathogenesis-related (PR) proteins, but they displayed no symptoms of cell death. Fucan oligosaccharides also induced the systemic accumulation of SA and the acidic PR protein PR-1, two markers of systemic acquired resistance (SAR). Consistently, fucan oligosaccharides strongly stimulated both local and systemic resistance to tobacco mosaic virus (TMV). The use of transgenic plants unable to accumulate SA indicated that, as in the SAR primed by TMV, SA is required for the establishment of oligofucan-induced resistance.
Mol Plant Microbe Interact 2003 Feb
PMID:Sulfated fucan oligosaccharides elicit defense responses in tobacco and local and systemic resistance against tobacco mosaic virus. 1257 45

Acidovorax avenae causes a brown stripe disease in monocot plants. We recently reported that a rice-incompatible strain of A. avenae caused hypersensitive cell death in rice and that the flagellin of the incompatible strain was involved in this response. The incompatible strain induced the rapid generation of H2O2 accompanying hypersensitive cell death and the expression of defense genes such as PAL, Cht-1, PBZ1, and LOX, whereas the compatible strain did not. The purified incompatible flagellin also induced the expression of PAL, Cht-1, and PBZ1, but LOX expression was not induced by the incompatible flagellin. PAL and LOX enzymatic activities were increased by inoculation with the incompatible strain, whereas only PAL activity was increased by the incompatible flagellin. Interestingly, the flagellin-deficient incompatible strain lost the ability to generate H2O2 and induce hypersensitive cell death, but PAL, Cht-1, and PBZ1 expression still were induced by inoculation with the deficient strain, suggesting that induction of these genes is regulated not only by flagellin but also by some other signal. Thus, the incompatible flagellin of A. avenae is a specific elicitor in rice, but it is not the only factor capable of inducing the rice defense system.
Mol Plant Microbe Interact 2003 May
PMID:Flagellin from an incompatible strain of Acidovorax avenae mediates H2O2 generation accompanying hypersensitive cell death and expression of PAL, Cht-1, and PBZ1, but not of Lox in rice. 1274 13

The phytotoxic protein PcF (Phytophthora cactorum-Fragaria) is a 5.6-kDa cysteine-rich, hydroxyproline-containing protein that is secreted in limited amounts by P. cactorum, an oomycete pathogen of tomato, strawberry and other relevant crop plants. Although we have shown that pure PcF triggers plant reactivity, its mechanism of action is not yet understood. Here we show that PcF, like other known fungal protein elicitors involved in pathogen-plant interaction, stimulates the activity of the defense enzyme phenylalanine ammonia lyase (EC 4.3.1.5) in tomato seedlings. Recognizing that a key step in understanding the mechanism of action of PcF at a molecular level is knowledge of its three-dimensional structure, we overexpressed this protein extracellularly in Pichia pastoris. The preliminary structural and functional characterization of a recombinant PcF homologue, N4-rPcF, is reported. Interestingly, although N4-rPcF is devoid of proline hydroxylation and has four additional amino acid residues attached to its N terminus, its secondary structure and biological activity are indistinguishable from wild-type PcF.
Cell Mol Life Sci 2003 Jul
PMID:PcF protein from Phytophthora cactorum and its recombinant homologue elicit phenylalanine ammonia lyase activation in tomato. 1294 33

Recent studies demonstrate that presenilins (PSs) and signal peptide peptidase (SPP) are members of a novel protease family of integral membrane proteins that may utilize a catalytic mechanism similar to classic aspartic proteases such as pepsin, renin and cathepsin D. The defining features of the PSs and SPP are their ability to cleave substrate polypeptides within a transmembrane region, the presence of two active site aspartate residues in adjacent membrane-spanning regions and a conserved PAL motif near their COOH-terminus. PSs appear to be the catalytic subunit of multiprotein complexes that possess gamma-secretase activity. Because this activity generates the amyloid beta peptide (Abeta) deposited in the brain of patients with Alzheimer's disease (AD), PSs are considered therapeutic targets in AD. In contrast to PSs that are not active unless part of a larger complex, SPP does not appear to require protein co-factors. Because of its requirement for hepatitis C virus maturation and a possible immune modulatory role, SPP is also considered a potential therapeutic target. Four additional PS/SPP homologs have been identified in humans; yet, their functions have not been elucidated. Herein, we will review the recent advances in our understanding of the PS/SPP family of proteases as well as discuss aspects of intramembrane cleavage that are not well understood.
Hum Mol Genet 2003 Oct 15
PMID:Intramembrane-cleaving aspartic proteases and disease: presenilins, signal peptide peptidase and their homologs. 1296 28

As the cowpea rust fungus penetrates the wall of a cowpea epidermal cell, resistant and susceptible plants exhibit different ultrastructural and cytochemical changes within the epidermal protoplast. To examine plant gene expression at this stage of infection, cytoplasm was extracted from individual inoculated or uninoculated epidermal cells before the fungal penetration peg reached the cell lumen. Initial differential colony hybridization screening of an expressed sequence tag library constructed from globally amplified cDNAs generated from the inoculated resistant cells resulted in 80 clones (out of 835) with a differential hybridization pattern. Further slot-blot screening and screening of the amplified cDNAs generated from inoculated or uninoculated, resistant or susceptible cells revealed 28 separate genes, mostly with no matching sequences in the databases, that were up-regulated in response to the growth of the fungus through the wall of resistant or susceptible cells. Five genes, including those coding for beta- and alpha-tubulin, were found to be down-regulated specifically in inoculated, susceptible cells, and five were specifically up-regulated in inoculated, resistant cells, including a PR-10 homolog and a phenylalanine ammonia-lyase gene. Probing the amplified cDNAs from each cell type for the expression of cell death-related genes revealed that an LLS1 homolog (vuLLS1), cloned from cowpea, was up-regulated by infection in both resistant and susceptible cells and that a homolog of HSR203J was differentially up-regulated in resistant cells. These data show that changes in gene expression predicting the subsequent expression of susceptibility or hypersensitive resistance to fungal infection occur prior to the fungus entering the cell lumen.
Mol Plant Microbe Interact 2003 Sep
PMID:cDNAs generated from individual epidermal cells reveal that differential gene expression predicting subsequent resistance or susceptibility to rust fungal infection occurs prior to the fungus entering the cell lumen. 1297 7

Rehmannia glutinosa is a medicinal herb that is tolerant to the non-selective herbicide paraquat. Acteoside, a phenolic compound present in the plant, has been shown to inhibit paraquat. To understand regulation of the phenylpropanoid pathway that produces the acteoside moiety, we isolated a phenylalanine ammonia-lyase (PAL) cDNA clone (RgPAL1) and used it to examine PAL expression. The deduced 712 amino acid sequence of the open reading frame contains the conserved active site and potential phosphorylation sites of other plant PALs. RgPAL1 mRNA was detected in the leaves, flowers and roots of healthy plants, and the level of the mRNA was higher in leaves than in flowers and roots. RgPAL1 mRNA was induced in leaves by paraquat, H2O2, UV light, wounding, yeast extract, jasmonic acid and ethephon. The transcript level and enzyme activity increased gradually from 6 to 24 h after exposure to paraquat or jasmonic acid. Induction of RgPAL1 by paraquat and stress-related phytohormones suggests that it is involved in the regulation of the phenylpropanoid pathway under oxidative stress.
Mol Cells 2003 Aug 31
PMID:Induction of phenylalanine ammonia-lyase gene expression by paraquat and stress-related hormones in Rehmannia glutinosa. 1450 42

The crystal structure of a Man/Glc-specific lectin from the seeds of the bloodwood tree (Pterocarpus angolensis), a leguminous plant from central Africa, has been determined in complex with mannose and five manno-oligosaccharides. The lectin contains a classical mannose-specificity loop, but its metal-binding loop resembles that of lectins of unrelated specificity from Ulex europaeus and Maackia amurensis. As a consequence, the interactions with mannose in the primary binding site are conserved, but details of carbohydrate-binding outside the primary binding site differ from those seen in the equivalent carbohydrate complexes of concanavalin A. These observations explain the differences in their respective fine specificity profiles for oligomannoses. While Man(alpha1-3)Man and Man(alpha1-3)[Man(alpha1-6)]Man bind to PAL in low-energy conformations identical with that of ConA, Man(alpha1-6)Man is required to adopt a different conformation. Man(alpha1-2)Man can bind only in a single binding mode, in sharp contrast to ConA, which creates a higher affinity for this disaccharide by allowing two binding modes.
J Mol Biol 2004 Jan 30
PMID:Structural basis of oligomannose recognition by the Pterocarpus angolensis seed lectin. 1472 39

Phenylketonuria (PKU) is an inborn error of amino acid metabolism caused by phenylalanine hydroxylase (PAH) deficiency. Dietary treatment has been the cornerstone for controlling systemic phenylalanine (Phe) levels in PKU for the past 4 decades. Over the years, it has become clear that blood Phe concentration needs to be controlled for the life of the patient, a difficult task taking into consideration that the diet becomes very difficult to maintain. Therefore alternative models of therapy are being pursued. This review describes the progress made in enzyme replacement therapy for PKU. Two modalities are discussed, PAH and phenylalanine ammonia-lyase PAH. Developing stable and functional forms of both enzymes has proven difficult, but recent success in producing polyethylene glycol-modified forms of active and stable PAH shows promise.
Mol Ther 2004 Aug
PMID:Trends in enzyme therapy for phenylketonuria. 1529 68

During mammalian vascular development, endothelial cells form a complex array of vessels that differ markedly in structure and function, but the molecular basis for this vascular complexity is poorly understood. Recent insights into endothelial diversity have come from the identification of molecular markers expressed on distinct endothelial cell populations. One such marker, the PAL-E antibody, has been used for almost 20 years to distinguish blood and lymphatic vessels, but the identity of the protein recognized by PAL-E has been unknown. In the present study we have used protein purification and tandem mass spectrometry analysis of tryptic peptides to identify the PAL-E antigen as a secreted form of vimentin. Vimentin has been well characterized as an intracellular intermediate filament protein expressed broadly in mesenchymal cells. In contrast, PAL-E-reactive vimentin is secreted extracellularly, its synthesis is restricted to a distinct population of blood endothelial cells and activated macrophages, and PAL-E-reactive vimentin is found in circulating human blood. PAL-E-reactive vimentin does not arise from an endothelial cell-specific mRNA transcript but is the product of cell-specific posttranslational modification. The PAL-E antibody therefore defines secretion of vimentin as a molecular distinction among endothelial cells and exposes a novel, extracellular role for vimentin in the blood vasculature.
Mol Cell Biol 2004 Oct
PMID:The endothelial cell-specific antibody PAL-E identifies a secreted form of vimentin in the blood vasculature. 1545 90


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