Novel Protein Kinases Associated with Calcineurin B-Like Calcium Sensors in Arabidopsis

Shi, Jinrui; Kim, Kyungnam; Ritz, Olga; Albrecht, Verónica; Gupta, Rajeev; Harter, Klaus; Luan, Sheng; Kudla, Jörg

doi:10.2307/3870963

Cited by 84 publications

(121 citation statements)

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“…Membranes were kept in a blocking buffer (phosphate-buffered saline, 1% bovine serum albumin, and 0.05% Tween 20) at room temperature for 1 h, then incubated with the 0.5% His-TaWIN1 fusion protein in the same buffer at room temperature for 1 h. Immunological detection was performed as described above. 6 clones by the yeast two-hybrid system, isolated three clones that activated two reporter genes, HIS3 and lacZ. Sequence analysis revealed that two were derived from the same gene and were designated as TaWIN1 (Triticum aestivum WPK4-interacting factor 1).…”

Section: Methodsmentioning

confidence: 99%

Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

Ikeda

Koizumi

Kusano

et al. 2000

Journal of Biological Chemistry

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WPK4 is a wheat protein kinase related to the yeast protein kinase SNF1, which plays a role in catabolite repression. To identify proteins involved in signal transduction through WPK4, we performed yeast two-hybrid screens and isolated two cDNA clones designated as TaWIN1 and TaWIN2. Both encode 14-3-3 proteins that, upon autophosphorylation, bind the C-terminal regulatory domain of WPK4. Mutational analysis through amino acid substitution revealed that TaWIN1 and TaWIN2 primarily bind WPK4 through phosphoserines at the positions 388 and 418, both located in the C-terminal region. Mutations in the conserved residues of the TaWIN1 amphipathic groove impaired the ability of TaWIN1 to bind to WPK4. A screen for in vitro phosphorylation of proteins involved in nutrient metabolism revealed a putative WPK4 substrate, nitrate reductase; its hinge 1 region was efficiently phosphorylated by WPK4. Subsequent far Western blots showed that it specifically bound TaWIN1. Since nitrate reductase has been shown to be inactivated by phosphorylation upon 14-3-3 binding, the present findings strongly suggest that WPK4 is the protein kinase responsible for controlling the nitrogen metabolic pathway, assembling the nitrate reductase and 14-3-3 complex through its phosphorylation specificity.

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Section: Methodsmentioning

confidence: 99%

Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

Ikeda

Koizumi

Kusano

et al. 2000

Journal of Biological Chemistry

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“…A family of sucrose nonfermenting-like protein kinases has been identified as targets for CBL proteins (7)(8)(9). These are serine-threonine protein kinases, referred to as AtCIPK (A. thaliana CBL-interacting protein kinase), that form a novel family of proteins found so far only in plants.…”

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confidence: 99%

The Crystal Structure of the Novel Calcium-binding Protein AtCBL2 from Arabidopsis thaliana

Nagae

Nozawa

Koizumi

et al. 2003

Journal of Biological Chemistry

113

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Arabidopsis thaliana calcineurin B-like protein (AtCBL2)is a member of a recently identified family of calcineurin B-like calcium-binding proteins in A. thaliana. The crystal structure of AtCBL2 has been determined at 2.1 Å resolution. The protein forms a compact ␣-helical structure with two pairs of EF-hand motifs. The structure is similar in overall folding topology to the structures of calcineurin B and neuronal calcium sensor 1, but differs significantly in local conformation. The two calcium ions are coordinated in the first and fourth EF-hand motifs, whereas the second and third EF-hand motifs are maintained in the open form by internal hydrogen bonding without coordination of calcium ions. Both a possible site and a possible mechanism for the target binding to AtCBL2 are discussed based on the three-dimensional structure.

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“…Calcineurin B-like (CBL) proteins are a unique family of calcium sensors in plants (14,15). The CBL proteins function by interacting with and regulating a unique family of plant protein kinases (called CIPKs for CBL-interacting protein kinases) (15)(16)(17)(18)(19). The presence of multigene families of CBLs and CIPKs in Arabidopsis suggests that CBL-CIPK network may be involved in a number of signaling processes in plants (20 -22, ‡).…”

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confidence: 99%

A Ca ²⁺ signaling pathway regulates a K ⁺ channel for low-K response in Arabidopsis

Kim

Cheong

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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403

303

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Nutrient sensing is critical for plant adaptation to the environment. Because of extensive farming and erosion, low content of mineral nutrients such as potassium (K ؉ ) in soils becomes a limiting factor for plant growth. In response to low-K conditions, plants enhance their capability of K ؉ uptake through an unknown signaling mechanism. Here we report the identification of a Ca 2؉ -dependent pathway for low-K response in Arabidopsis. We are not aware of any other example of a molecular pathway for a nutrient response in plants. Earlier genetic analyses revealed three genes encoding two Ca 2؉ sensors (CBL1 and CBL9) and their target protein kinase (CIPK23) to be critical for plant growth on low-K media and for stomatal regulation, indicating that these calcium signaling components participate in the low-K response and turgor regulation. In this study, we show that the protein kinase CIPK23 interacted with, and phosphorylated, a voltage-gated inward K ؉ channel (AKT1) required for K ؉ acquisition in Arabidopsis. In the Xenopus oocyte system, our studies showed that interacting calcium sensors (CBL1 and CBL9) together with target kinase CIPK23, but not either component alone, activated the AKT1 channel in a Ca 2؉ -dependent manner, connecting the Ca 2؉ signal to enhanced K ؉ uptake through activation of a K ؉ channel. Disruption of both CBL1 and CBL9 or CIPK23 gene in Arabidopsis reduced the AKT1 activity in the mutant roots, confirming that the Ca 2؉ -CBL-CIPK pathway functions to orchestrate transporting activities in planta according to external K ؉ availability.calcium signaling ͉ potassium channel ͉ nutrient sensing ͉ potassium uptake ͉ protein kinase P lants and microbes are able to adapt to widely varying environmental conditions, including the availability of inorganic nutrients. The response to K ϩ is especially relevant because it is the major inorganic osmoticum that contributes to turgor pressure and, hence, to cellular growth and development (1, 2). Both plants and fungi maintain internal K ϩ near 100 mM even when extracellular K ϩ varies between 1 M and 100 mM (i.e., over five orders of magnitude in free concentration). A large collection of transporters is required for this homeostatic mechanism (3-6), yet little is known about the mechanism underlying regulation and integration of the transport activities in concert with the extracellular K ϩ levels. Some studies suggest that plants enhance their capability of K ϩ uptake by activating some K ϩ transporters in response to K ϩ -deficient conditions (7-10). A signaling process exists for the plants to ''monitor'' external K ϩ concentration and ''respond'' to the low-K condition by enhancing the capability for K ϩ acquisition. This signaling pathway represents a typical nutrient sensing and response process in plants about which our knowledge is extremely limited. One recent study indicates that low-K status in the soil triggers elevated production of H 2 O 2 that may serve as a signaling molecule to alter the expression of certain genes (11). Becaus...

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Novel Protein Kinases Associated with Calcineurin B-Like Calcium Sensors in Arabidopsis

Cited by 84 publications

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Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

The Crystal Structure of the Novel Calcium-binding Protein AtCBL2 from Arabidopsis thaliana

A Ca ²⁺ signaling pathway regulates a K ⁺ channel for low-K response in Arabidopsis

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Novel Protein Kinases Associated with Calcineurin B-Like Calcium Sensors in Arabidopsis

Cited by 84 publications

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Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

Specific Binding of a 14-3-3 Protein to Autophosphorylated WPK4, an SNF1-related Wheat Protein Kinase, and to WPK4-phosphorylated Nitrate Reductase

The Crystal Structure of the Novel Calcium-binding Protein AtCBL2 from Arabidopsis thaliana

A Ca 2+ signaling pathway regulates a K + channel for low-K response in Arabidopsis

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A Ca ²⁺ signaling pathway regulates a K ⁺ channel for low-K response in Arabidopsis