Characterization of DNA sequences encoding a novel isoform of the 55 kDa B regulatory subunit of the type 2A protein serine/threonine phosphatase of Arabidopsis thaliana

Corum, J. Willis; Hartung, Andrew J.; Stamey, Robin T.; Rundle, Sabine J.

doi:10.1007/bf00021804

Cited by 30 publications

(13 citation statements)

References 25 publications

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“…As shown in Figure 5A, RCN1 was expressed in all organs, suggesting additional roles for RCN1 (Corum et al, 1996;Garbers et al, 1996). ABA mediates dormancy by inhibiting seed germination.…”

Section: The Rcn1 Disruption Mutation Reduces Aba Sensitivity In Seedsmentioning

confidence: 95%

Disruption of a Guard Cell–Expressed Protein Phosphatase 2A Regulatory Subunit, RCN1, Confers Abscisic Acid Insensitivity in Arabidopsis

et al. 2002

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Pharmacological studies have led to a model in which the phytohormone abscisic acid (ABA) may be positively transduced via protein phosphatases of the type 1 (PP1) or type 2A (PP2A) families. However, pharmacological evidence also exists that PP1s or PP2As may function as negative regulators of ABA signaling. Furthermore, recessive disruption mutants in protein phosphatases that function in ABA signal transduction have not yet been identified. A guard cell-expressed PP2A gene, RCN1, which had been characterized previously as a molecular component affecting auxin transport and gravity response, was isolated. A T-DNA disruption mutation in RCN1 confers recessive ABA insensitivity to Arabidopsis. The rcn1 mutation impairs ABA-induced stomatal closing and ABA activation of slow anion channels. Calcium imaging analyses show a reduced sensitivity of ABA-induced cytosolic calcium increases in rcn1, whereas mechanisms downstream of cytosolic calcium increases show wild-type responses, suggesting that RCN1 functions in ABA signal transduction upstream of cytosolic Ca(2+) increases. Furthermore, rcn1 shows ABA insensitivity in ABA inhibition of seed germination and ABA-induced gene expression. The PP1 and PP2A inhibitor okadaic acid phenocopies the rcn1 phenotype in wild-type plants both in ABA-induced cytosolic calcium increases and in seed germination, and the wild-type RCN1 genomic DNA complements rcn1 phenotypes. These data show that RCN1 functions as a general positive transducer of early ABA signaling.

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Section: The Rcn1 Disruption Mutation Reduces Aba Sensitivity In Seedsmentioning

confidence: 95%

Disruption of a Guard Cell–Expressed Protein Phosphatase 2A Regulatory Subunit, RCN1, Confers Abscisic Acid Insensitivity in Arabidopsis

et al. 2002

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“…Little is known about the functions of the two Arabidopsis PP2A 55-kDa B subunit isoforms that carry five degenerate WD-40 repeats (Table 2) and show 43-48% amino acid sequence identity with yeast and animal B subunits [35]. Arabidopsis has nine PP2A B 0 subunits, of which only AtB 0 a and AtB 0 b contain putative nuclear targeting sequences.…”

Section: Protein Phosphatasementioning

confidence: 99%

Arabidopsis PPP family of serine/threonine phosphatases

Farkas

Dombrádi

Miskei

et al. 2007

Trends in Plant Science

195

219

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“…cDNAs for PP2AA2 and PP2AA3 have been isolated previously and were designated AtAb/DF1 and AtAg/ DF2, respectively (Slabas et al, 1994, Corum et al, 1996. The predicted PP2AA2 and PP2AA3 proteins show 94% amino acid sequence identity with each other and 86% identity with RCN1.…”

Section: Isolation Of Regulatory a Subunit Mutantsmentioning

confidence: 99%

Disparate Roles for the Regulatory A Subunit Isoforms in Arabidopsis Protein Phosphatase 2A

et al. 2004

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The heterotrimeric protein phosphatase 2A (PP2A) complex comprises a catalytic subunit and regulatory A and B subunits that modulate enzyme activity and mediate interactions with other proteins. We report here the results of a systematic analysis of the Arabidopsis (Arabidopsis thaliana) regulatory A subunit gene family, which includes the ROOTS CURL IN NAPHTHYLPHTHALAMIC ACID1 (RCN1), PP2AA2, and PP2AA3 genes. All three A subunit isoforms accumulate in the organs of seedlings and adult plants, suggesting extensive overlap in expression domains. We have isolated pp2aa2 and pp2aa3 mutants and found that their phenotypes are largely normal and do not resemble that of rcn1. Whereas rcn1 pp2aa2 and rcn1 pp2aa3 double mutants exhibit striking abnormalities in all stages of development, the pp2aa2 pp2aa3 double mutant shows only modest defects. Together, these data suggest that RCN1 performs a cardinal role in regulation of phosphatase activity and that PP2AA2 and PP2AA3 functions are unmasked only when RCN1 is absent.

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Characterization of DNA sequences encoding a novel isoform of the 55 kDa B regulatory subunit of the type 2A protein serine/threonine phosphatase of Arabidopsis thaliana

Cited by 30 publications

References 25 publications

Disruption of a Guard Cell–Expressed Protein Phosphatase 2A Regulatory Subunit, RCN1, Confers Abscisic Acid Insensitivity in Arabidopsis

Disruption of a Guard Cell–Expressed Protein Phosphatase 2A Regulatory Subunit, RCN1, Confers Abscisic Acid Insensitivity in Arabidopsis

Arabidopsis PPP family of serine/threonine phosphatases

Disparate Roles for the Regulatory A Subunit Isoforms in Arabidopsis Protein Phosphatase 2A

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