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

Kwak, June M.; Moon, Jiwon; Murata, Yoshiyuki; Kuchitsu, Kazuyuki; Leonhardt, Nathalie; DeLong, Alison; Schroeder, Julian I.

doi:10.1105/tpc.003335

Cited by 190 publications

(197 citation statements)

References 89 publications

(168 reference statements)

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“…The RCN1 protein was also shown to be involved in regulation of stomatal aperture in Arabidopsis (Kwak et al, 2002). The rcn1-1 mutant was impaired in abscisic acid-induced stomatal closing and showed reduced abscisic acid-induced calcium increases.…”

Section: Discussionmentioning

confidence: 99%

The Arabidopsis rcn1-1 Mutation Impairs Dephosphorylation of Phot2, Resulting in Enhanced Blue Light Responses

Tseng

Briggs

2010

The Plant Cell

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Phototropins (phot) sense blue light through the two N-terminal chromophore binding LOV domains and activate the C-terminal kinase domain. The resulting phototropin autophosphorylation is essential for biological activity. We identified the A1 subunit of Ser/Thr protein phosphatase 2A (PP2A) as interacting with full-length phot2 in yeast and also interacting with phot2 in an in vitro protein binding assay. Phenotypic characterizations of a phot1-5 rcn1-1 (for root curling in n-naphthylphthalamic acid1) double mutant, in which phot2 is the only functional phototropin and PP2A activity is reduced, showed enhanced phototropic sensitivity and enhanced blue light-induced stomatal opening, suggesting that PP2A activity is involved in regulating phot2 function. When treated with cantharidin, a chemical inhibitor of PP2A, the phot1-5 mutant exhibited enhanced phot2-mediated phototropic responses like those of the phot1-5 rcn1-1 double mutant. Immunoblot analysis to examine phot2 endogenous phosphorylation levels and in vitro phosphorylation assays of phot2 extracted from plants during dark recovery from blue light exposure confirmed that phot2 is more slowly dephosphorylated in the reduced PP2A activity background than in the wild-type PP2A background, suggesting that phosphorylated phot2 is a substrate of PP2A activity. While reduced PP2A activity enhanced the activity of phot2, it did not enhance either phot1 dephosphorylation or the activity of phot1 in mediating phototropism or stomatal opening.

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Section: Discussionmentioning

confidence: 99%

The Arabidopsis rcn1-1 Mutation Impairs Dephosphorylation of Phot2, Resulting in Enhanced Blue Light Responses

Tseng

Briggs

2010

The Plant Cell

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“…PP2AA1 is considered to have a cardinal role in seedlings. Although morphologically similar to the wild type, PP2AA1 mutants display abnormal ethylene and ABA responses, as well as perturbed polar auxin transport [22][23][24][25] . PP2AA2 and PP2AA3 functions are unmasked only in a pp2aa1 mutant background 25 and neither pp2aa2 and pp2aa3 mutant nor pp2aa2-a3 double mutant plants have altered morphological phenotypes per se (see ref.…”

Section: Ton1mentioning

confidence: 99%

A protein phosphatase 2A complex spatially controls plant cell division

et al. 2013

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In the absence of cell migration, the orientation of cell divisions is crucial for body plan determination in plants. The position of the division plane in plant cells is set up premitotically via a transient cytoskeletal array, the preprophase band, which precisely delineates the cortical plane of division. Here we describe a protein complex that targets protein phosphatase 2A activity to microtubules, regulating the transition from the interphase to the premitotic microtubule array. This complex, which comprises TONNEAU1 and a PP2A heterotrimeric holoenzyme with FASS as regulatory subunit, is recruited to the cytoskeleton via the TONNEAU1-recruiting motif family of proteins. Despite the acentrosomal nature of plant cells, all members of this complex share similarity with animal centrosomal proteins involved in ciliary and centriolar/centrosomal functions, revealing an evolutionary link between the cortical cytoskeleton of plant cells and microtubule organizers in other eukaryotes.

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“…The eer1 mutant results from a loss-of-function mutation in the protein phosphatase 2A A regulatory subunit, RCN1 (Larsen and Cancel, 2003). This gene has also been implicated in regulating auxin responses in roots and abscisic acid signaling in guard cells (Garbers et al, 1996;Kwak et al, 2002) Figure 5. Genetic mapping of Gr and Nr-2 loci to tomato chromosome 1.…”

Section: Ethylene Signaling Specificitymentioning

confidence: 99%

Ethylene Insensitivity Conferred by theGreen-ripeandNever-ripe 2Ripening Mutants of Tomato

et al. 2005

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The ripening of a fleshy fruit represents the summation of an array of biochemical processes that are regulated by interactions between developmental programs and environmental inputs. Analysis of tomato (Solanum lycopersicum) mutants and inhibitor studies indicate that ethylene is necessary for full development of the ripening program of climacteric fruit such as tomato, yet ethylene alone is not sufficient. This suggests that an interaction between ethylene and nonethylene (or developmental) pathways mediates ripening. In this study, we have examined the physiological basis for ripening inhibition of the dominant Green-ripe (Gr) and Never-ripe 2 (Nr-2) mutants of tomato. Our data suggest that this inhibition is due to ethylene insensitivity in mutant fruit. Further investigation of ethylene responses in Gr and Nr-2 plants also revealed weak ethylene insensitivity during floral senescence and abscission and, during inhibition of root elongation, a phenotype associated with the triple response. However, ethylene-induced inhibition of hypocotyl elongation and petiole epinasty are normal in Gr and Nr-2, suggesting that these loci regulate a subset of ethylene responses. We have mapped both dominant mutations to a 2-cM overlapping region of the long arm of chromosome 1 of tomato, a region not previously linked to any known ethylene signaling loci. The phenotypic similarity and overlapping map location of these mutations suggest Gr and Nr-2 may be allelic and may possibly encode a novel component of the ethylene response pathway.The ripening of a fruit represents the culmination of a series of biochemical processes that have evolved as a mechanism of seed dispersal. In the case of fleshy fruits, the changes that occur during ripening impart desirable characteristics to the fruit such as bright colors, softening, and sugar and volatile accumulation that attract animals and birds to aid dispersal. Fruits also form an essential component of the human diet providing sources of sugars, fiber, vitamins, minerals, and antioxidants. Therefore, the study of fruit ripening is of importance to both basic plant biology and agriculture.Although there is great diversity in fruit anatomy and phenotypes, the biochemical changes that occur during ripening are conserved in many plant species. For example, research carried out on diverse species indicates that at the onset of ripening there is often a coordinated increase in gene expression and enzyme activity of many proteins involved in cell wall metabolism, pigment synthesis, and sugar metabolism (Seymour et al., 1993). These data suggest that the genetic mechanisms that regulate fruit ripening are likely conserved. Little is known of the identities of these genetic pathways, although experiments, largely performed using tomato (Solanum lycopersicum), have led to the hypothesis that ripening in climacteric fruits such as tomato, banana, apple, and stone fruits is regulated by ethylene dependent and independent pathways (Adams-Phillips et al., 2004a;Giovannoni, 2004).The involvement...

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

Cited by 190 publications

References 89 publications

The Arabidopsis rcn1-1 Mutation Impairs Dephosphorylation of Phot2, Resulting in Enhanced Blue Light Responses

The Arabidopsis rcn1-1 Mutation Impairs Dephosphorylation of Phot2, Resulting in Enhanced Blue Light Responses

A protein phosphatase 2A complex spatially controls plant cell division

Ethylene Insensitivity Conferred by theGreen-ripeandNever-ripe 2Ripening Mutants of Tomato

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