Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cDNA clone was selected as a candidate for the catalytic subunit of phospho-pyruvate dehydrogenase phosphatase (PDP) by screening a Zea mays expressed sequence tag database with the bovine PDP deduced amino acid sequence. Both strands of the cDNA were completely sequenced. The maize clone contains an open reading frame of 1098 base pairs that encodes a polypeptide of 40 127 Da, ZMPP2. The deduced amino acid sequence of ZMPP2 contains the five PP2C signature domains, as does PDP. However, the expression pattern of ZMPP2, determined by reverse transcriptase-polymerase chain reaction, was different from those of the maize pyruvate dehydrogenase E1 alpha subunit and pyruvate dehydrogenase kinase. Additionally, the predicted subcellular location of ZMPP2 is cytoplasmic, while the pyruvate dehydrogenase complex, regulated by reversible phosphorylation, is mitochondrial. Thus, ZMPP2 is a PP2C-type protein phosphatase related to but distinct from PDP.
J Exp Bot 2001 Aug
PMID:ZMPP2, a novel type-2C protein phosphatase from maize. 1147 40

NO (nitric oxide) production from sunflower plants (Helianthus annuus L.), detached spinach leaves (Spinacia oleracea L.), desalted spinach leaf extracts or commercial maize (Zea mays L.) leaf nitrate reductase (NR, EC 1.6.6.1) was continuously followed as NO emission into the gas phase by chemiluminescence detection, and its response to post-translational NR modulation was examined in vitro and in vivo. NR (purified or in crude extracts) in vitro produced NO at saturating NADH and nitrite concentrations at about 1% of its nitrate reduction capacity. The K(m) for nitrite was relatively high (100 microM) compared to nitrite concentrations in illuminated leaves (10 microM). NO production was competitively inhibited by physiological nitrate concentrations (K(i)=50 microM). Importantly, inactivation of NR in crude extracts by protein phosphorylation with MgATP in the presence of a protein phosphatase inhibitor also inhibited NO production. Nitrate-fertilized plants or leaves emitted NO into purified air. The NO emission was lower in the dark than in the light, but was generally only a small fraction of the total NR activity in the tissue (about 0.01-0.1%). In order to check for a modulation of NO production in vivo, NR was artificially activated by treatments such as anoxia, feeding uncouplers or AICAR (a cell permeant 5'-AMP analogue). Under all these conditions, leaves were accumulating nitrite to concentrations exceeding those in normal illuminated leaves up to 100-fold, and NO production was drastically increased especially in the dark. NO production by leaf extracts or intact leaves was unaffected by nitric oxide synthase inhibitors. It is concluded that in non-elicited leaves NO is produced in variable quantities by NR depending on the total NR activity, the NR activation state and the cytosolic nitrite and nitrate concentration.
J Exp Bot 2002 Jan
PMID:Regulation of nitric oxide (NO) production by plant nitrate reductase in vivo and in vitro. 1174 Oct 46

Regulating the intracellular Na+/K+ ratio is an essential process for salinity tolerance. The yeast mutant, can, which is deficient in calcineurin, can not grow on medium containing Na+ because it is unable to regulate the intracellular Na+/K+ ratio. Expression of the STO gene of Arabidopsis thaliana in the can mutant complements the salt-sensitive phenotype. A protein of Arabidopsis, an H-protein promoter binding factor (HPPBF-1), that binds to STO protein was isolated. HPPBF-1 cDNA has a sequence encoding a Myb DNA binding-motif and its gene expression is induced by salt stress. Furthermore, HPPBF-1 protein is localized in the nucleus. Although, the expression level of STO is not induced under salt-stress conditions, overexpression of STO in a transgenic Arabidopsis plant gave it a higher salt tolerance than was observed in the wild type. When STO transgenic plants and wild-type plants were subjected to salt stress, root growth was increased by 33-70% in the transgenic plants under salt stress. These results suggest that STO is involved in salt-stress responses in Arabidopsis.
J Exp Bot 2003 Oct
PMID:Salt tolerance-related protein STO binds to a Myb transcription factor homologue and confers salt tolerance in Arabidopsis. 1290 88

Protein reserves in the cereal endosperm are sequentially degraded to small peptides and amino acids during germination and these are translocated across the scutellum to support growth of the embryo. Peptide transport in the germinating barley grain is mediated by specific carriers localized to the plasma membrane of the scutellar epithelium. In isolated barley embryos peptide transport is rapidly inhibited by amino acid concentrations comparable with those found in the post-germination barley grain. However, this inhibition of HvPTR1 activity is not effected at either the transcriptional or translational level. The protein phosphatase inhibitor okadaic acid repressed transport of Ala-[14C]Phe, but not [14C]Ala, into the barley scutellar epithelium. In vivo [32P]orthophosphate labelling studies of barley scutellar tissue in combination with immunoprecipitation studies using antiserum raised to HvPTR1 showed that HvPTR1 (66 kDa) is phosphorylated in the presence of amino acids. Immunopurified HvPTR1 was further demonstrated to be phosphorylated on serine residues. Digestion with the N-glycosidase enzyme PNGase F results in a shift in the molecular mass of the protein by 10 kDa, indicating that HvPTR1 is an N-linked glycoprotein. These results provide strong circumstantial evidence that HvPTR1 peptide transport activity in the germinating barley grain is regulated at the post-translational level by phosphorylation in response to rising levels of amino acids emanating from the endosperm as a result of storage protein breakdown and mobilization. This is potentially an important element in balancing the flux of organic nitrogen and carbon from the endosperm to embryo during germination and seedling establishment.
J Exp Bot 2005 Jun
PMID:A role for phosphorylation in the regulation of the barley scutellar peptide transporter HvPTR1 by amino acids. 1582 72

SPICK2, a homologue of the weakly-inward-rectifying Shaker-like Arabidopsis K channel, AKT2, is a candidate K+-influx channel participating in light- and clock-regulated leaf movements of the legume, Samanea saman. Light and the biological clock regulate the in situ K+-influx channel activity differentially in extensor and flexor halves of the pulvinus (the S. saman leaf motor organ), and also-though differently-the transcript level of SPICK2 in the pulvinus. This disparity between the in situ channel activity versus its candidate transcript, along with the sequence analysis of SPICK2, suggest an in situ regulation of the activity of SPICK2, possibly by phosphorylation and/or by interaction with cAMP. Consistent with this (i) the activity of the voltage-dependent K+-selective fraction of the inward current in extensor and flexor cells was affected differentially in whole-cell patch-clamp assays promoting phosphorylation (using the protein phosphatase inhibitor okadaic acid); (ii) several proteins in isolated plasma membrane-enriched vesicles of the motor cells underwent phosphorylation without an added kinase in conditions similar to patch-clamp; and (iii) the SPICK2 protein was phosphorylated in vitro by the catalytic subunit of the broad-range cAMP-dependent protein kinase. All of these results are consistent with the notion that SPICK2 is the K+-influx channel, and is regulated in vivo directly by phosphorylation.
J Exp Bot 2006
PMID:Phosphorylation of SPICK2, an AKT2 channel homologue from Samanea motor cells. 1696 80

The present study supports the view that the retinoblastoma functions are shared by two distinct retinoblastoma-related (RBR) protein subfamilies in the monocot cereal species, whereas dicot plants have only a single RBR protein. Genes encoding RBR proteins were identified and characterized in alfalfa (Medicago sativa), rice (Oryza sativa), and wheat (Triticum aestivum). The alfalfa MsRBR gene encodes a new member of the dicot RBR proteins (subfamily A). A comparison was made of two rice genes, OsRBR1 (subfamily B) and OsRBR2 (subfamily C), which exhibit differences in exon-intron organization and share only 52% amino acid sequence identity. The plant RBR proteins can be categorized into three distinct subfamilies, in which the similarity between members is greater than the similarity to other RBR proteins from the same species. Comparison of the transcript levels in various tissues revealed that the expression of the OsRBR1 gene was high in embryos or cultured cells and gradually decreased from the basal region to the tip of the leaves. The OsRBR2 gene displayed more transcripts in differentiated tissues, such as leaves and roots. In contrast, the mRNA level of the MsRBR gene did not differ significantly in either mature leaves or cultured cells. The results of yeast two-hybrid pairwise interaction assays demonstrated differences between the rice RBR variants in the interactions with the phosphatase 2A B'' regulatory subunit and an unknown protein. The in silico and functional data presented in this work highlight considerable differences between dicot and monocot species in the retinoblastoma regulatory pathways and permit an improved classification of RBR proteins in higher plants.
J Exp Bot 2007
PMID:Dicot and monocot plants differ in retinoblastoma-related protein subfamilies. 1738 86

Protein kinases and phosphatases are the foremost agents which take part in cell cycle regulation in both plants and other eukaryotes. Protein kinases are a very well examined group of proteins with respect to chemical structure and function. Nowadays protein phosphatases, including PP1 and PP2A belonging to the PSP family, are the focus of interest. Okadaic acid (OA) which is a specific inhibitor of protein phosphatase activity is widely used to study them. In the present research, the involvement of OA-sensitive phosphatases in the regulation of progression of the plant cell cycle was analysed (in planta) using Vicia faba root meristems synchronized with hydroxyurea and divided into five series. Each series was treated with 1 muM OA for 3 h for different time periods corresponding to the consecutive cell cycle phases. The results showed that in the OA-treated cells DNA replication and mitosis began earlier than in the control cells, since G(1) and G(2) phases were significantly shorter and the H1 histone kinases activity was higher. Moreover, autoradiography and morphological analyses of mitotic figures revealed that the OA-treated cells entered mitosis before the end of heterochromatin replication. An immunocytochemical search showed that earlier initiation of S phase in the OA-treated cells correlated with more abundant phosphorylation of Rb-like protein in comparison with the control cells. OA also induced significant condensation of metaphase chromosomes and blocked metaphase-anaphase transition.
J Exp Bot 2007
PMID:Okadaic acid (1 microM) accelerates S phase and mitosis but inhibits heterochromatin replication and metaphase anaphase transition in Vicia faba meristem cells. 1760 30

As many as three distinct signalling pathways and their messengers-entailing changes in cytoplasmic-free Ca(2+) ([Ca(2+)](i)), cytoplasmic pH (pH(i)) and protein phosphorylation-may underpin K(+) and anion channel control during stomatal movements. Such a degree of redundancy is probably not unique among plant cells, and is wholly consistent with the ability of the guard cells to integrate the wide range of environmental and hormonal stimuli that affect stomatal aperture. In principle, signal convergence enables a spectrum of graded responses extending beyond simple interference ('crosstalk'): it allows one pathway to gate transmission via the next, so boosting or muting the final 'integrated signal' that reaches the effector. Current evidence supports such a role for the ABI1 protein phosphatase and, by inference, protein kinase elements in gating K(+) channel sensitivity to pH(i) and ABA. In turn, gating of changes in [Ca(2+)](i) may also be subject to pH(i). Because these signal pathways affect discrete subsets of ion channels at the guard cell plasma membrane, their coupling may be seen to add a further layer of control necessary for co-ordinating the ensemble of channel response during stomatal movements.
J Exp Bot 1997 Mar
PMID:Signal redundancy, gates and integration in the control of ion channels for stomatal movement. 2124 29

In the present study abscisic acid-induced stomatal closing, and malate effects on stomatal apertures were analysed in the presence of guard cell ion channel regulators. A recent study has suggested that abscisic acid (ABA) activation of protein kinases and/or inhibition of protein phosphatases may be central to activation of guard cell slow anion channels and mediation of stomatal closing in Vicia faba (Schmidt et al., 1995). These findings were confirmed and extended in the present study showing that both in Vicia faba and in Commelina communis ABA-induced stomatal closings were abolished by kinase inhibitors and enhanced by the protein phosphatase inhibitor okadaic acid. Further detailed studies demonstrate that very high 40 mM extracellular malate concentrations are required to close stomata only partially and that okadaic acid also enhances malate-induced stomatal closing. In addition, when stomata are widely opened, even at 40 mM malate concentrations, no malate effect on stomatal apertures was observed. This finding may be explained by a complete inactivation of guard cell anion channels when stomatal apertures are opened very widely and suggests that extracellular malate cannot function as a primary CO(2) signal in stomatal regulation. The G-protein regulators mastoparan and mas7 as well as neomycin showed no significant effects on light-induced stomatal opening and ABA-induced stomatal closing. Findings reported here correlate closely to recent findings on slow anion channel regulation in guard cells and support the hypothesis that activation of these anion channels by phosphorylation events and complete inactivation by dephosphorylation events is a rate-limiting component in guard cell signal transduction. Furthermore, the presented data support a model in which ABA-activation of protein kinases and/or inhibition of okadaic acidsensitive protein phosphatases is central to ABA regulation of stomatal movements in Vicia faba and Commelina communis.
J Exp Bot 1997 Mar
PMID:Characterization of ion channel modulator effects on ABA- and malate-induced stomatal movements: strong regulation by kinase and phosphatase inhibitors, and relative insensitivity to mastoparans. 2124 30

In order to characterize the potential transcriptional regulation of core components of abscisic acid (ABA) signal transduction in tomato fruit development and drought stress, eight SlPYL (ABA receptor), seven SlPP2C (type 2C protein phosphatase), and eight SlSnRK2 (subfamily 2 of SNF1-related kinases) full-length cDNA sequences were isolated from the tomato nucleotide database of NCBI GenBank. All SlPYL, SlPP2C, and SlSnRK2 genes obtained are homologous to Arabidopsis AtPYL, AtPP2C, and AtSnRK2 genes, respectively. Based on phylogenetic analysis, SlPYLs and SlSnRK2s were clustered into three subfamilies/subclasses, and all SlPP2Cs belonged to PP2C group A. Within the SlPYL gene family, SlPYL1, SlPYL2, SlPYL3, and SlPYL6 were the major genes involved in the regulation of fruit development. Among them, SlPYL1 and SlPYL2 were expressed at high levels throughout the process of fruit development and ripening; SlPYL3 was strongly expressed at the immature green (IM) and mature green (MG) stages, while SlPYL6 was expressed strongly at the IM and red ripe (RR) stages. Within the SlPP2C gene family, the expression of SlPP2C, SlPP2C3, and SlPP2C4 increased after the MG stage; SlPP2C1 and SlPP2C5 peaked at the B3 stage, while SlPP2C2 and SlPP2C6 changed little during fruit development. Within the SlSnRK2 gene family, the expression of SlSnRK2.2, SlSnRK2.3, SlSnRK2.4, and SlSnRK2C was higher than that of other members during fruit development. Additionally, most SlPYL genes were down-regulated, while most SlPP2C and SlSnRK2 genes were up-regulated by dehydration in tomato leaf.
J Exp Bot 2011 Nov
PMID:Transcriptional regulation of SlPYL, SlPP2C, and SlSnRK2 gene families encoding ABA signal core components during tomato fruit development and drought stress. 2187 32


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