Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinases in animals, elicits the transient activation of a 45-kDa protein kinase in tobacco cell-suspension cultures. The 45-kDa protein kinase preferentially phosphorylates myelin basic protein (MBP), a general substrate for MAPK. Studies using cycloheximide indicated that protein synthesis is not required for the activation of the kinase. Treatment of tobacco cell extracts containing the activated kinase with either serine/threonine-specific or tyrosine-specific protein phosphatase abolished the kinase activity, which consequently appears to be regulated by phosphorylation. By using an immune complex kinase assay with antibodies specific for stress-responsive MAPKs, we show that the PMA-activated kinase is immunologically related to the wound-induced protein kinase (WIPK), and not to the salicylic acid-induced protein kinase (SIPK), two representative members of the tobacco MAPK family, known to be activated by extracellular stimuli. Furthermore, the activated kinase was recognized by phospho-specific MAPK antibodies. Collectively, these results indicate that phorbol ester promotes the activation of a 45-kDa protein kinase related to WIPK in tobacco cells. Activation of WIPK in response to PMA is associated with protein phosphorylation but not with an increase in protein level.
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PMID:A 45-kDa protein kinase related to mitogen-activated protein kinase is activated in tobacco cells treated with a phorbol ester. 1185 45

Elicitors of plant defence reactions, oligogalacturonides and cryptogein, an elicitin produced by Phytophthora cryptogea, were previously shown to induce a rapid and transient activation of two mitogen-activated protein kinases (MAPKs) in cells of tobacco [ Nicotiana tabacum L. cv. Xanthi; A. Lebrun-Garcia et al. (1998) Plant J 15:773-781]. We verified that these two MAPKs correspond to the salicylic acid-induced protein kinase (SIPK) and the wound-induced protein kinase (WIPK). The involvement of salicylic acid (SA) in cryptogein-induced MAPK activation was investigated using transgenic NahG tobacco cells expressing the salicylate hydroxylase gene and thus unable to accumulate SA. The large and sustained activation of both MAPKs by cryptogein was maintained in transgenic cells compared with non-transgenic tobacco cells. Moreover, weak acids, namely SA, 4-hydroxybenzoic acid, an ineffective analogue of SA in plant resistance, and butyric acid acidified the cytosol, a physiological event also induced by cryptogein, but activated both MAPKs only slightly and transiently in tobacco cells. These results indicate that MAPK activation by cryptogein is not mediated by SA, that cytosolic acidification can be transduced by MAPKs, and that in cryptogein-treated cells, cytosolic acidification should contribute poorly to MAPK activation.
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PMID:Questioning the role of salicylic acid and cytosolic acidification in mitogen-activated protein kinase activation induced by cryptogein in tobacco cells. 1188 49

A gene encoding a receptor-like protein kinase was isolated as the gene induced in the early period of N gene-dependent hypersensitive cell death in tobacco leaves. The kinase domain expressed as a glutathione S-transferase fusion protein was capable of autophosphorylation, indicating that this gene encodes an active protein kinase. A high level of the transcript accumulated before necrotic lesion formation in tobacco mosaic virus (TMV)-inoculated tobacco leaves carrying the N gene but it was low in a tobacco cultivar lacking the N gene. A small but reproducible increase in the transcript was found 1-2 h after a temperature shift from 30 degrees C to 20 degrees C even in healthy leaves, suggesting the gene expression is temperature sensitive. The gene was named WRK for wound-induced receptor-like protein kinase, because the transcript increased to a maximum within 15-30 min of wounding. In suspension cultured tobacco cells, an increase in the transcript was found 15 min after transfer to a new medium, but it was suppressed under high osmotic pressures. The wound-induced WRK accumulation was enhanced by cycloheximide treatment, but not by known defense signal compounds (salicylic acid, jasmonic acid, 1-aminocyclopropan-1-carboxylic acid and abscisic acid) and some plant hormones. Thus, WRK is a wound-inducible and temperature-sensitive protein kinase gene induced before hypersensitive cell death probably through unknown signaling pathways.
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PMID:Induced expression of a temperature-sensitive leucine-rich repeat receptor-like protein kinase gene by hypersensitive cell death and wounding in tobacco plant carrying the N resistance gene. 1191 80

The Pti4, Pti5, and Pti6 proteins from tomato were identified based on their interaction with the product of the Pto disease resistance gene, a Ser-Thr protein kinase. They belong to the ethylene-response factor (ERF) family of plant-unique transcription factors and bind specifically to the GCC-box cis element present in the promoters of many pathogenesis-related (PR) genes. Here, we show that these tomato ERFs are localized to the nucleus and function in vivo as transcription activators that regulate the expression of GCC box-containing PR genes. Expression of Pti4, Pti5, or Pti6 in Arabidopsis activated the expression of the salicylic acid-regulated genes PR1 and PR2. Expression of jasmonic acid- and ethylene-regulated genes, such as PR3, PR4, PDF1.2, and Thi2.1, was affected differently by each of the three tomato ERFs, with Arabidopsis-Pti4 plants having very high levels of PDF1.2 transcripts. Exogenous application of salicylic acid to Arabidopsis-Pti4 plants suppressed the increased expression of PDF1.2 but further stimulated PR1 expression. Arabidopsis plants expressing Pti4 displayed increased resistance to the fungal pathogen Erysiphe orontii and increased tolerance to the bacterial pathogen Pseudomonas syringae pv tomato. These results indicate that Pti4, Pti5, and Pti6 activate the expression of a wide array of PR genes and play important and distinct roles in plant defense.
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PMID:Tomato transcription factors pti4, pti5, and pti6 activate defense responses when expressed in Arabidopsis. 1197 Nov 37

In search for components of MAPK (mitogen-activated protein kinase) cascades in rice (Oryza sativa L. cv. Nipponbare), we identified a single copy gene called OsMSRMK2 from jasmonic acid (JA) treated rice seedling leaf cDNA library. This gene has a conserved protein kinase domain, including a MAPK family signature, and encodes a 369 amino acid polypeptide with a predicted molecular mass of 42995.43 and a pI of 5.48. OsMSRMK2 did not show constitutive expression in leaves and was induced within 15 min in response to wounding by cut. Using in vitro system, we show that the expression of OsMSRMK2 mRNA was potently enhanced within 15 min by signalling molecules, protein phosphatase inhibitors, ultraviolet irradiation, fungal elicitor, heavy metals, high salt and sucrose, and drought. OsMSRMK2 expression was further modulated by co-application of JA, salicylic acid, and ethylene and required de novo synthesized protein factor(s) in its transient regulation. Moreover, high (37 degrees C) and low temperatures (12 degrees C) and environmental pollutants-ozone and sulfur dioxide-differentially regulate the OsMSRMK2 mRNA accumulation in leaves of intact plants. Present results demonstrating dramatic transcriptional and transient regulation of the OsMSRMK2 expression by diverse biotic/abiotic stresses, a first report for any rice (or plant) MAPK to date, suggest a role for OsMSRMK2 in rice defense/stress response pathways.
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PMID:Isolation of novel rice (Oryza sativa L.) multiple stress responsive MAP kinase gene, OsMSRMK2, whose mRNA accumulates rapidly in response to environmental cues. 1207 77

Three genes (i.e., a zinc finger protein, a lectin-like protein, and AtMPK3), previously shown to respond to chitin elicitation in microarray experiments, were used to examine the response of Arabidopsis spp. to chitin addition. Maximum induction for all three genes was found upon addition of crab-shell chitin at 100 mg per liter. Threefold induction was found with a chitin concentration as low as 10(-4) mg per liter. The specificity of this response was examined using purified chitin oligomers (degree of polymerization = 2 to 8). The larger chitin oligomers (hexamer to octamer), were most effective in inducing expression of the three genes assayed. Gene induction was observed after the addition of 1 nM chitin octamer. The protein kinase inhibitors staurosporine and K252a effectively suppressed chitin-induced gene expression, while the protein phosphatase inhibitors calyculin A and okadaic acid induced the accumulation of mRNA in the absence of chitin. The phosphorylation event necessary for transmission of the chitin signal was completed within the first 20 min of chitin addition. The level of chitin-induced gene expression of the lectin-like protein and AtMPK3 was not significantly changed in mutants blocked in the jasmonic acid (JA, jar1)-, ethylene (ein2)-, or salicylic acid (SA, pad4, npr1, and eds5)-dependent pathway. In contrast, expression of mRNA for the zinc finger protein was reduced in the mutants affected in the JA- or SA-dependent pathway.
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PMID:Characterization of early, chitin-induced gene expression in Arabidopsis. 1223 3

Combinations of ethylene and methyl jasmonate (E/MeJA) synergistically induced members of both groups 1 and 5 of the pathogenesis-related (PR) superfamily of defense genes. E/MeJA caused a synergistic induction of PR-1b and osmotin (PR-5) mRNA accumulation in tobacco seedlings. E/MeJA also synergistically activated the osmotin promoter fused to a [beta]-glucuronidase marker gene in a tissue-specific manner. The E/MeJA responsiveness of the osmotin promoter was localized on a -248 to +45 fragment that exhibited responsiveness to several other inducers. E/MeJA induction also resulted in osmotin protein accumulation to levels similar to those induced by osmotic stress. Of the several known inducers of the osmotin gene, including salicylic acid (SA), fungal infection is the only other condition known to cause substantial osmotin protein accumulation in Wisconsin 38, a tobacco cultivar that does not respond hypersensitively to tobacco mosaic virus. Based on the ability of the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine to block ethylene induction of PR-1b mRNA accumulation and its inability to block osmotin mRNA induction by ethylene, these two PR gene groups appeared to have at least partially separate signal transduction pathways. Stimulation of osmotin mRNA accumulation by okadaic acid indicated that another protein kinase system is involved in regulation of the osmotin gene. SA, which is known to induce pathogen resistance in tobacco, could not induce the osmotin gene as much as E/MeJA and neither could it induce PR-1b as much as SA and MeJA combined.
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PMID:Plant Defense Genes Are Synergistically Induced by Ethylene and Methyl Jasmonate. 1224 67

The effects of the fungal toxin fusicoccin (FC) on the tomato (Lycopersicon esculentum Mill.) transcriptome were analyzed in the context of defense-related genes using a spotted microarray of 235 cDNAs. Pronounced changes in transcript abundance were observed for 64 (27%) of the represented genes. FC appears to have an antagonistic effect on wound and pathogen defense responses, in that it causes the induction of pathogenesis-related and the down-regulation of wound response genes. The transcripts for many proteins involved in photosynthesis and carbohydrate metabolism were strongly repressed. Genes related to the biosynthesis of jasmonic acid and aromatic amino acids, on the other hand, were found to be up-regulated. In addition to these expression changes, which occurred rather late after FC treatment, rapid and transient induction kinetics were observed for a small group of genes encoding a calcium-dependent protein kinase, two mitogen-activated protein kinases, a matrix metalloproteinase and a homologue of the respiratory burst oxidase. These genes have not been described previously in tomato, nor has their regulation by FC been reported. Salicylic acid was shown not to be required for the induction of these transcripts and a function for the respective proteins in the FC-induced, salicylic acid-independent activation of pathogenesis-related genes is discussed.
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PMID:cDNA microarray analysis of fusicoccin-induced changes in gene expression in tomato plants. 1243 17

The active defense of plants against pathogens often includes rapid and localized cell death known as hypersensitive response (HR). Protein phosphorylation and dephosphorylation are implicated in this event based on studies using protein kinase and phosphatase inhibitors. Recent transient gain-of-function studies demonstrated that the activation of salicylic acid-induced protein kinase (SIPK) and wounding-induced protein kinase (WIPK), two tobacco mitogen-activated protein kinases (MAPKs) by their upstream MAPK kinase (MAPKK), NtMEK2 leads to HR-like cell death. Here, we report that the conserved kinase interaction motif (KIM) in MAPKKs is required for NtMEK2 function. Mutation of the conserved basic amino acids in this motif, or the deletion of N-terminal 64 amino acids containing this motif significantly compromised or abolished the ability of NtMEK2DD to activate SIPK/WIPK in vivo. These mutants were also defective in interacting with SIPK and WIPK, suggesting protein-protein interaction is required for the functional integrity of this MAPK cascade. To eliminate Agrobacterium that is known to activate a number of defense responses in transient transformation experiments, we generated permanent transgenic plants. Induction of NtMEK2DD expression by dexamethasone induced HR-like cell death in both T1 and T2 plants. In addition, by using PVX-induced gene silencing, we demonstrated that the suppression of all three known components in the NtMEK2-SIPK/WIPK pathway attenuated N gene-mediated TMV resistance. Together with previous report that SIPK and WIPK are activated by TMV in a gene-for-gene-dependent manner, we conclude that NtMEK2-SIPK/WIPK pathway plays a positive role in N gene-mediated resistance, possibly through regulating HR cell death.
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PMID:Function of a mitogen-activated protein kinase pathway in N gene-mediated resistance in tobacco. 1260 44

In pathogen-infected or wounded tobacco plants, the activation of wound-induced protein kinase (WIPK), a tobacco mitogen-activated protein kinase, has been implicated in the defense response. However, no endogenous signal responsible for the activation has been identified. A WIPK-activating substance was isolated from tobacco leaves and identified as (11E,13E)-labda-11,13-diene-8alpha,15-diol, designated WAF-1. When applied in nanomolar concentrations to leaves, either natural WAF-1 or chemically synthesized WAF-1 activated WIPK as well as salicylic acid-induced protein kinase, a tobacco mitogen-activated protein kinase, and enhanced the accumulation of transcripts of wound- and pathogen-inducible defense-related genes. Quantitative analysis of endogenous WAF-1 revealed that levels increased rapidly in leaves during a hypersensitive response to Tobacco mosaic virus (TMV) and after wounding. Furthermore, treatment of leaves with WAF-1 resulted in enhanced resistance to TMV infection. These results suggest that WAF-1 functions as an endogenous signal to mediate the defense responses of tobacco plants to TMV infection and wounding.
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PMID:A diterpene as an endogenous signal for the activation of defense responses to infection with tobacco mosaic virus and wounding in tobacco. 1267 Oct 83


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