<i>Arabidopsis</i>
            ABA Response Gene
            <i>ABI1</i>
            : Features of a Calcium-Modulated Protein Phosphatase

Leung, Jeffrey; Bouvier-Durand, Michelle; Morris, P. I.; Guerrier, D.; Chefdor, Françoise; Giraudat, Jérôme

doi:10.1126/science.7910981

Cited by 761 publications

(584 citation statements)

References 36 publications

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“…In comparison with wild-type a general decrease of basic AtP5CS1 mRNA levels was observed in of ornithine to P5C occurs preferentially under normal conditions, whereas the conversion of glutamate to P5C the abi1-1 mutant, also in the absence of salt induction. In contrast, the axr2 mutation did not affect the basic AtP5CS1 is dominant under stress (Rhodes et al, 1986), the expression and activity of P5CS was proposed to directly mRNA levels, but reduced the induction of AtP5CS1 mRNA accumulation during salt treatment. A similar effect of control the accumulation of proline in response to salinity and dehydration (Delauney and Verma, 1993).…”

Section: Nacl-induced P5cs Mrna Accumulation In Arabidopsismentioning

confidence: 81%

Differential expression of two P5CS genes controlling proline accumulation during salt‐stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis

Strizhov¹,

et al. 1997

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Proline is a common compatible osmolyte in higher plants. Proline accumulation in response to water stress and salinity is preceded by a rapid increase of the mRNA level of Δ1‐pyrroline‐5‐carboxylate synthase (P5CS) controlling the rate‐limiting step of glutamate‐derived proline biosynthesis. P5CS is encoded by two differentially regulated genes in Arabidopsis. Gene AtP5CS1AtP5CS1 mapped to chromosome 2‐78.5 is expressed in most plant organs, but silent in dividing cells. Gene AtP5CS2 located close to marker m457 on chromosome 3–101.3 contributes 20–40% of total P5CS mRNA in plant tissues, but is solely responsible for the synthesis of abundant P5CS mRNA in rapidly dividing cell cultures. Accumulation of AtP5CS transcripts is regulated in a tissue specific manner and inducible by drought, salinity, ABA, and to a lesser extent by auxin. Induction of AtP5CS1 mRNA accumulation in salt‐treated seedlings involves an immediate early transcriptional response regulated by ABA signalling that is not inhibited by cycloheximide, but abolished by the deficiency of ABA biosynthesis in the aba1 Arabidopsis mutant. However, inhibition of protein synthesis by cycloheximide prevents the induction of AtP5CS2 mRNA accumulation, and blocks further increase of AtP5CS1 mRNA levels during the second, slow phase of salt‐induction. Mutations abi1 and axr2, affecting ABA‐perception in Arabidopsis, reduce the accumulation of both AtP5CS mRNAs during salt‐stress, whereas ABA‐signalling functions defined by the abi2 and abi3 mutations have no effect on salt‐induction of the AtP5CS genes.

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Section: Nacl-induced P5cs Mrna Accumulation In Arabidopsismentioning

confidence: 81%

Differential expression of two P5CS genes controlling proline accumulation during salt‐stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis

Strizhov¹,

et al. 1997

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“…Subsequently 2-DE, in conjunction with immunoblotting, revealed that the heterogeneity of cruciferin isoforms far exceeded that predicted from the limited number of expressed genes and mRNA variants described above (Figure 3). The PP2C encoded by ABI1 has been implicated in the regulation of kinase signalling during seed development [29,30], and the abi1-1 mutant is known to exhibit pleiotropic effects. However, specific ABI1 targets have not yet been identified [33].…”

Section: Resultsmentioning

confidence: 99%

“…The ABI1 locus encodes a unique type of protein phosphatase in that the C-terminal domain possesses serine/ threonine protein phosphatase activity similar to that of PP2Cs (class 2C phosphatases), whereas the N-terminal domain contains a calcium-binding EF-hand motif that generally occurs only in the heterodimeric PP2B-type serine/threonine phosphatases. A single point mutation in the abi1-1 mutant significantly reduces PP2C activity [29,30], and genome-wide gene expression profiling indicates that ABA gene regulation is impaired [45]. Although recombinant fusion proteins containing either the whole ABI1 protein or only the phosphatase domain display in vitro phosphatase activity towards 32 P-labelled casein [46,47]; the in vivo targets have not yet been identified.…”

Section: Is Cruciferin An In Vivo Target For the Abi1 Protein Phosphamentioning

confidence: 99%

“…In the process, we discovered that the most abundant phosphorylated seed protein was cruciferin, and that multiple phosphorylation sites could be identified using LC-MS/MS (liquid chromatography-tandem MS). Since PP2C (protein phosphatase 2C), which is encoded by ABI1, has been implicated in the regulation of ABA (abscisic acid)-dependent kinase signalling during seed development [29,30], we also examined protein phosphorylation in the abi1-1 mutant, in which PP2C activity is significantly reduced. We found that cruciferin is hyperphosphorylated in this mutant and is, therefore, a probable target for the ABI1 protein phosphatase.…”

Section: Introductionmentioning

confidence: 99%

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Phosphorylation of the 12 S globulin cruciferin in wild-type and abi1-1 mutant Arabidopsis thaliana (thale cress) seeds

Wan

Ross

Yang

et al. 2007

Biochemical Journal

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Cruciferin (a 12 S globulin) is the most abundant storage protein in the seeds of Arabidopsis thaliana (thale cress) and other crucifers, sharing structural similarity with the cupin superfamily of proteins. Cruciferin is synthesized as a precursor in the rough endoplasmic reticulum. Subunit assembly is accompanied by structural rearrangements involving proteolysis and disulfidebond formation prior to deposition in protein storage vacuoles. The A. thaliana cv. Columbia genome contains four cruciferin loci, two of which, on the basis of cDNA analysis, give rise to three alternatively spliced variants. Using MS, we confirmed the presence of four variants encoded by genes At4g28520.1, At5g44120.3, At1g03880.1 and At1g3890.1 in A. thaliana seeds. Two-dimensional gel electrophoresis, along with immunological detection using anti-cruciferin antiserum and antibodies against phosphorylated amino acid residues, revealed that cruciferin was the major phosphorylated protein in Arabidopsis seeds and that polymorphism far exceeded that predicted on the basis of known isoforms. The latter may be attributed, at least in part, to phosphorylation site heterogeneity. A total of 20 phosphorylation sites, comprising nine serine, eight threonine and three tyrosine residues, were identified by MS. Most of these are located on the IE (interchain disulfide-containing) face of the globulin trimer, which is involved in hexamer formation. The implications of these findings for cruciferin processing, assembly and mobilization are discussed. In addition, the protein phosphatase 2C-impaired mutant, abi1-1, was found to exhibit increased levels of cruciferin phosphorylation, suggesting either that cruciferin may be an in vivo target for this enzyme or that abi1-1 regulates the protein kinase/phosphatase system required for cruciferin phosphorylation.

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“…These mutations were isolated 25-years ago by genetic screenings in Arabidopsis, aimed to the identification of ABAinsensitive mutants [27] and the cloning of the mutant loci provided pioneering insights into ABA signaling [28,29,30,31]. Both abi1-1D and abi2-1D are strong ABA-insensitive mutants that show diminished response to ABA in seeds and vegetative tissues, however, analysis of lossof-function alleles indicates that ABI1 and ABI2 gene products, as well as other clade A PP2Cs, are negative regulators of ABA signaling [32,33,34,35].…”

Section: Abi1-1 G180d Abi2-1 G168d and Hab1 G246d Hypermorphic Enzymesmentioning

confidence: 99%

Structural insights into PYR/PYL/RCAR ABA receptors and PP2Cs

et al. 2012

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Abscisic acid (ABA) plays an essential function in plant physiology since it is required for biotic and abiotic stress responses as well as control of plant growth and development. A new family of soluble ABA receptors, named PYR/PYL/RCAR, has emerged as ABA sensors able to inhibit the activity of specific protein phosphatases type-2C (PP2Cs) in an ABAdependent manner. The structural and functional mechanism by which ABA is perceived by these receptors and consequently leads to inhibition of the PP2Cs has been recently elucidated. The module PYR/PYL/RCAR-ABA-PP2C offers an elegant and unprecedented mechanism to control phosphorylation signaling cascades in a ligand-dependent manner. The knowledge of their three-dimensional structures paves the way to the design of ABA agonists able to modulate the plant stress response.

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Arabidopsis ABA Response Gene ABI1 : Features of a Calcium-Modulated Protein Phosphatase

Cited by 761 publications

References 36 publications

Differential expression of two P5CS genes controlling proline accumulation during salt‐stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis

Differential expression of two P5CS genes controlling proline accumulation during salt‐stress requires ABA and is regulated by ABA1, ABI1 and AXR2 in Arabidopsis

Phosphorylation of the 12 S globulin cruciferin in wild-type and abi1-1 mutant Arabidopsis thaliana (thale cress) seeds

Structural insights into PYR/PYL/RCAR ABA receptors and PP2Cs

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