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)

The perception of abiotic stresses and signal transduction to switch on adaptive responses are critical steps in determining the survival and reproduction of plants exposed to adverse environments. Plants have stress-specific adaptive responses as well as responses which protect the plants from more than one environmental stress. There are multiple stress perception and signalling pathways, some of which are specific, but others may cross-talk at various steps. Recently, progress has been made in identifying components of signalling pathways involved in salt, drought and cold stresses. Genetic analysis has defined the Salt-Overly-Sensitive (SOS) pathway, in which a salt stress-induced calcium signal is probably sensed by the calcium-binding protein SOS3 which then activates the protein kinase SOS2. The SOS3-SOS2 kinase complex regulates the expression and activity of ion transporters such as SOS1 to re-establish cellular ionic homeostasis under salinity. The ICE1 (Inducer of CBF Expression 1)-CBF (C-Repeat Binding Protein) pathway is critical for the regulation of the cold-responsive transcriptome and acquired freezing tolerance, although at present the signalling events that activate the ICE1 transcription factor during cold stress are not known. Both ABA-dependent and -independent signalling pathways appear to be involved in osmotic stress tolerance. Components of mitogen-activated protein kinase (MAPK) cascades may act as converging points of multiple abiotic as well as biotic stress signalling pathways. Forward and reverse genetic analysis in combination with expression profiling will continue to uncover many signalling components, and biochemical characterization of the signalling complexes will be required to determine specificity and cross-talk in abiotic stress signalling pathways.
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PMID:Molecular genetic perspectives on cross-talk and specificity in abiotic stress signalling in plants. 1467 35

Arabidopsis thaliana has a number of response regulators (ARRs) implicated in the histidine (His)-->aspartate (Asp) phosphorelay signal transduction. According to the current consistent model, both the type-A and type-B ARR family members play crucial roles in the cytokinin signaling circuitry. However, this higher plant has a few extra ARRs, on which no attention has been paid so far. Characterization of these extra ARRs might provide us with new insight into the His-->Asp phosphorelay signal transduction in plants. For this reason, in this study we extensively examined the natures of such a representative (named ARR22). Transcripts of ARR22 were expressed predominantly in reproductive organs, and a GFP::ARR22 fusion protein was localized in the cytoplasmic space in onion epidermal cells. The purified ARR22 protein had the ability to undergo phosphorylation in vitro, when incubated with phospho-AHP5, indicating that ARR22 has the fundamental ability to participate into a His-Asp phosphorelay pathway in its own right. In plants, transgenic lines overexpressing ARR22 were characterized (referred to as ARR22-ox), which showed the characteristic dwarf phenotypes with poorly developed root systems. The results of Northern blot hybridization with selected sets of hormone-responsive genes suggested that cytokinin responses are selectively attenuated in ARR22-ox, while other hormone responses (auxin, ABA and ethylene) occur normally. The results of microarray analyses with cytokinin-treated wild-type and ARR22-ox plants further supported the view that cytokinin responses are globally attenuated in ARR22-ox, at least, at the level of gene regulation. Finally, we demonstrated that the dwarf phenotypes of ARR22-ox are very similar to those of the wooden leg (wol) mutant, which has a severe lesion in the AHK4/CRE1 cytokinin-receptor of histidine protein kinase. These results suggested that ARR22 might also be implicated, directly or indirectly, in the cytokinin-responsive His-->Asp phophorelay signal transduction.
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PMID:Arabidopsis response regulator, ARR22, ectopic expression of which results in phenotypes similar to the wol cytokinin-receptor mutant. 1535 32

The mitogen-activated protein kinase (MAPK) cascade is involved in responses to biotic and abiotic stress in plants. In this study, we isolated a new MAPK, NtMPK4, which is a tobacco homolog of Arabidopsis MPK4 (AtMPK4). NtMPK4 was activated by wounding along with two other wound-responsive tobacco MAPKs, WIPK and SIPK. We found that NtMPK4 was activated by salicylic acid-induced protein kinase kinase (SIPKK), which has been isolated as an SIPK-interacting MAPK kinase. In NtMPK4 activity-suppressed tobacco, wound-induced expression of jasmonic acid (JA)-responsive genes was inhibited. NtMPK4-silenced plants showed enhanced sensitivity to ozone. Inversely, transgenic tobacco plants, in which SIPKK or the constitutively active type SIPKK(EE) was overexpressed, exhibited greater responsiveness to wounding with enhanced resistance to ozone. We further found that NtMPK4 was expressed preferentially in epidermis, and the enhanced sensitivity to ozone in NtMPK4-silenced plants was caused by an abnormal regulation of stomatal closure in an ABA-independent manner. These results suggest that NtMPK4 is involved in JA signaling and in stomatal movement.
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PMID:A mitogen-activated protein kinase NtMPK4 activated by SIPKK is required for jasmonic acid signaling and involved in ozone tolerance via stomatal movement in tobacco. 1620 44

The plant hormone abscisic acid regulates gene expression in response to growth stimuli and abiotic stress. Previous studies have implicated members of the bZIP family of transcription factors as mediators of abscisic acid dependent gene expression through the ABRE cis-element. Here, we identify two new maize bZIP transcription factors, EmBP-2 and ZmBZ-1 related to EmBP-1 and OsBZ-8 families. They are differentially expressed during embryo development; EmBP-2 is constitutive, whereas ZmBZ-1 is abscisic acid-inducible and accumulates during late embryogenesis. Both factors are nuclear proteins that bind to ABREs and activate transcription of the abscisic acid-inducible gene rab28 from maize. EmBP-2 and ZmBZ-1 are phosphorylated by protein kinase CK2 and phosphorylation alters their DNA binding properties. Our data suggest that EmBP-2 and ZmBZ-1 are involved in the expression of abscisic acid inducible genes such as rab28 and their activity is modulated by ABA and by phosphorylation.
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PMID:Isolation and functional characterisation of two new bZIP maize regulators of the ABA responsive gene rab28. 1624 Jan 81

An enzymatically active recombinant protein kinase, previously isolated and characterized in Fagus sylvatica L. dormant seeds (FsPK1), was used to obtain a specific polyclonal antibody against this protein. Immunoblotting and immunohistochemical analysis of FsPK1 protein in beech seeds showed a strong immunostaining in the nucleus of the cells located in the vascular tissue of the embryonic axis corresponding to the future apical meristem of the root. This protein kinase was found to accumulate in the seeds only when embryo growth was arrested by application of ABA, while the protein amount decreased during stratification, previously proved to alleviate dormancy, and no protein was detected at all when seed germination was induced by addition of GA(3). These results indicate that FsPK1 may be involved in the control of the embryo growth mediated by ABA and GAs during the transition from dormancy to germination in Fagus sylvatica seeds.
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PMID:Immunolocalization of FsPK1 correlates this abscisic acid-induced protein kinase with germination arrest in Fagus sylvatica L. seeds. 1647 90

Stomatal pores of higher plants close in response to decreases in atmospheric relative humidity (RH). This is believed to be a mechanism that prevents the plant from losing excess water when exposed to a dry atmosphere and as such is likely to have been of evolutionary significance during the colonization of terrestrial environments by the embryophytes. We have conducted a genetic screen, based on infrared thermal imaging, to identify Arabidopsis genes involved in the stomatal response to reduced RH. Here we report the characterization of two genes, identified during this screen, which are involved in the guard cell reduced RH signaling pathway. Both genes encode proteins known to be involved in guard cell ABA signaling. OST1 encodes a protein kinase involved in ABA-mediated stomatal closure while ABA2 encodes an enzyme involved in ABA biosynthesis. These results suggest, in contrast to previously published work, that ABA plays a role in the signal transduction pathway connecting decreases in RH to reductions in stomatal aperture. The identification of OST1 as a component required in stomatal RH and ABA signal transduction supports the proposition that guard cell signaling is organized as a network in which some intracellular signaling proteins are shared among different stimuli.
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PMID:The identification of genes involved in the stomatal response to reduced atmospheric relative humidity. 1668 49

NtWIF is a transcription factor activated upon phosphorylation by wound-induced protein kinase (WIPK) in tobacco plants. Transgenic tobacco plants overexpressing NtWIF exhibited constitutive accumulation of transcripts for pathogenesis-related genes, PR-1a and PR-2. Salicylic acid levels were 50-fold higher than those in wild-type plants. The levels of jasmonic acid and IAA did not significantly differ, while an increase of ABA upon wounding was delayed by 3 h in the transgenics. When challenged with tobacco mosaic virus, lesions developed faster and were smaller in the transgenic plants. The results suggest that NtWIF is likely to influence salicylic acid biosynthesis, being located downstream of WIPK.
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PMID:Expression of a WIPK-activated transcription factor results in increase of endogenous salicylic acid and pathogen resistance in tobacco plants. 1681 10

The Arabidopsis thaliana RNA binding protein UBA2a is the closest homologue of the Vicia faba AKIP1 (56% identity). Like AKIP1, UBA2a is a constitutively-expressed nuclear protein and in response to ABA it is also reorganized within the nucleus in "speckles" suggesting a possible role of this protein in the regulation of mRNA metabolism during ABA signaling. AKIP1 interacts with, and is phosphorylated by, the upstream ABA-activated protein kinase AAPK. We have investigated if a pathway similar to that described in Vicia faba also exists in Arabidopsis. Our results showed that despite the resemblance between the corresponding Vicia and Arabidopsis proteins, it appears that the function of UBA2a is independent of OST1 phosphorylation.
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PMID:Arabidopsis RNA-binding protein UBA2a relocalizes into nuclear speckles in response to abscisic acid. 1682 85

A functional cloning approach using the oxidant-sensitive yeast mutant, Deltayap1, was employed to identify plant genes involved in tolerance of oxidative stress. In this screen, we identified an Arabidopsis late embryogenesis-abundant (LEA)-like protein, AtLEA5, which increased the tolerance of Deltayap1 cells to the oxidants H(2)O(2), diamide, menadione and tert-butyl hydroperoxide. Unlike canonical LEAs, AtLEA5 is constitutively expressed in roots and reproductive organs but not in seeds. In leaves of short-day grown plants, AtLEA5 transcripts exhibited a diurnal pattern of regulation, where transcripts were repressed in the light and abundant in the dark. Expression of AtLEA5 in leaves was induced by oxidants, ABA and dehydration. Use of abi1-1 (ABA-insensitive) and aba1-1 (ABA-deficient) Arabidopsis mutants indicated that drought induction of AtLEA5 required ABA synthesis but was independent of the ABI1 gene product. Abscisic acid and H(2)O(2) induction of AtLEA5 was also independent of the OXI1 protein kinase. Constitutive overexpression of AtLEA5 resulted in increased root growth and shoot biomass, both in optimal conditions and under H(2)O(2) stress. However, in comparison with wild type, photosynthesis in overexpressing plants was more susceptible to drought. These features suggest that AtLEA5 has a unique function among LEA proteins in that it plays a specific role in protection against oxidative stress involving decreased photosynthesis. This protein functions as part of a complex network of defences that contribute to robustness of plants under stress by minimizing the negative effects of oxidation.
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PMID:Yeast complementation reveals a role for an Arabidopsis thaliana late embryogenesis abundant (LEA)-like protein in oxidative stress tolerance. 1709 20

A number of signal pathways have been found through which abundant calcium-stimulated protein kinase activity in plant is associated with calcium-dependent protein kinases (CDPKs) which act as the calcium sensors mediating numerous responses, including hormone signaling. Basing on previous studies, we made additional functional analysis of the gene AtCPK30 encoding a protein kinase in Arabidopsis. Results of semi-quantitative reverse transcription PCR (RT-PCR) analysis indicated that AtCPK30 was highly expressed in root and induced by ABA, IAA, 2,4-D, GA(3) and 6-BA treatment. The physiological roles of AtCPK30 were studied using a gain-of-function approach. Seedlings of AtCPK30 transgenic lines had longer primary roots than those plants of wild-type at the early stages. Interestingly, when these plants grew on MS lack of Ca(2+) including wild-type and transgenic lines, the roots of transgenic line were more sensitive to calcium, lack of Ca(2+) had less effect on roots of transgenic lines than those of wild-type. Treated with several plant hormones, such as ABA, IAA, GA(3) and 6-BA, the roots of seedlings of transgenic line developed abnormally because they were more sensitive to hormones. Furthermore, NPA relatively less inhibited emergency of lateral roots of transgenic line than those of the wild-type. Green fluorescent protein-CPK30 (GFP-CPK30) fusion protein studies revealed the localization of AtCPK30 to both cell wall and plasma membrane. These results suggest that AtCPK30 acts as the calcium sensor and involved in the hormone-signaling pathways.
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PMID:A calcium-dependent protein kinase is involved in plant hormone signal transduction in Arabidopsis. 1755 10


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