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Chang, Liang‐Che; Yang, Woo Young; Browning, Karen S.; Roth, Don A.

doi:10.1023/a:1006379623534

Cited by 20 publications

(9 citation statements)

References 30 publications

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“…In the presence of nutrients, TOR blocks the action of GCN2 (general control nonrepressed 2) [79], a PK that inhibits translation initiation upon sensing the uncharged transfer RNAs that accumulate during amino acid limitation [80]. Interestingly, AtGCN2 complements the corresponding yeast mutant [81], and yeast GCN2 phosphorylates wheat eIF2α [82], suggesting that the GCN2 function might be conserved in plants (Figure 3). Future studies might unravel the molecular interactions among TOR, HXK1 and SnRK1 in plant nutrient, energy and stress signaling.…”

Section: Possible Links To Snrk1-mediated Energy Signalingmentioning

confidence: 99%

“…In nutrient-rich conditions, mTOR (mammalian TOR) promotes growth partly through regulation of the translational machinery [79] and blocks the translation-inhibitory pathway mediated by the amino-acid-deficiency-sensing GCN2 PK. Similar functions seem to apply to the plant TOR [76,77] and to some extent to GCN2 [81,82]. Plants could have evolved unique modes of interplay between the SnRK1 and TOR pathways.…”

Section: Figurementioning

confidence: 99%

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Convergent energy and stress signaling

Baena-González

Sheen

2008

Trends in Plant Science

488

372

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Plants are constantly confronted by multiple types of stress. Despite their distinct origin and mode of perception, nutrient deprivation and most stresses have an impact on the overall energy status of the plant, leading to convergent downstream responses that include largely overlapping transcriptional patterns. The emerging view is that this transcriptome reprogramming in energy and stress signaling is partly regulated by the evolutionarily conserved energy sensor protein kinases, SNF1 (sucrose non-fermenting 1) in yeast, AMPK (AMP-activated protein kinase) in mammals and SnRK1 (SNF1-related kinase 1) in plants. Upon sensing the energy deficit associated with stress, nutrient deprivation and darkness, SnRK1 triggers extensive transcriptional changes that contribute to restoring homeostasis, promoting cell survival and elaborating longer-term responses for adaptation, growth and development.

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Section: Possible Links To Snrk1-mediated Energy Signalingmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Convergent energy and stress signaling

Baena-González

Sheen

2008

Trends in Plant Science

488

372

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“…eIF2-Wheat eIF2␣ was previously cloned into pET30a(ϩ) for bacterial expression (28). The eIF2␣ coding region was amplified from this construct and cloned into the NdeI/BamHI site of pET15b(ϩ).…”

Section: Cloning Expression and Purification Of Ck2 Substratesmentioning

confidence: 99%

Differential Phosphorylation of Plant Translation Initiation Factors by Arabidopsis thaliana CK2 Holoenzymes

Dennis

Browning

2009

Journal of Biological Chemistry

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A previously described wheat germ protein kinase (Yan, T. F., and Tao, M. (1982) J. Biol. Chem. 257, 7037-7043) was identified unambiguously as CK2 using mass spectrometry. CK2 is a ubiquitous eukaryotic protein kinase that phosphorylates a wide range of substrates. In previous studies, this wheat germ kinase was shown to phosphorylate eIF2␣, eIF3c, and three large subunit (60 S) ribosomal proteins (Browning, K. S., Yan, T. F., Lauer, S. J., Aquino, L. A., Tao, M., and Ravel, J. M. (1985) Plant Physiol. 77, 370 -373). To further characterize the role of CK2 in the regulation of translation initiation, Arabidopsis thaliana catalytic (␣1 and ␣2) and regulatory (␤1, ␤2, ␤3, and ␤4) subunits of CK2 were cloned and expressed in Escherichia coli. Recombinant A. thaliana CK2␤ subunits spontaneously dimerize and assemble into holoenzymes in the presence of either CK2␣1 or CK2␣2 and exhibit autophosphorylation. The purified CK2 subunits were used to characterize the properties of the individual subunits and their ability to phosphorylate various plant protein substrates. CK2 was shown to phosphorylate eIF2␣, eIF2␤, eIF3c, eIF4B, eIF5, and histone deacetylase 2B but did not phosphorylate eIF1, eIF1A, eIF4A, eIF4E, eIF4G, eIFiso4E, or eIFiso4G. Differential phosphorylation was exhibited by CK2 in the presence of various regulatory ␤-subunits. Analysis of A. thaliana mutants either lacking or overexpressing CK2 subunits showed that the amount of eIF2␤ protein present in extracts was affected, which suggests that CK2 phosphorylation may play a role in eIF2␤ stability. These results provide evidence for a potential mechanism through which the expression and/or subcellular distribution of CK2 ␤-subunits could participate in the regulation of the initiation of translation and other physiological processes in plants.

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“…Activation of the UPR in cultured plant cells by the antibiotic tunicamycin (Tm), an inhibitor of N-linked protein glycosylation, triggers programmed cell death (9,10). Only a few homologs of proteins centrally involved in the UPR in other systems have been identified in plants: , eIF2␣ (14,15), and p58 IPK (16). Although the Arabidopsis genome has no immediate homologs of the ER stress-induced XBP1 or ATF6 genes, the Tm-inducible bZIP60 transcription factor contains a transmembrane domain and is activated by cleavage; hence, it may function in a manner analogous to that of ATF6 (17).…”

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confidence: 99%

Heterotrimeric G protein signaling in theArabidopsisunfolded protein response

Wang

Narendra

Fedoroff

2007

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

104

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We present evidence that heterotrimeric G protein signaling is involved in cell death associated with the unfolded protein response (UPR) in Arabidopsis. Seedlings of homozygous agb1-2 (G␤-null mutation) mutant plants are markedly more resistant to growth inhibition by the protein glycosylation inhibitor tunicamycin (Tm) than either wild-type plants or gpa1-4 (G␣-null mutation) mutants. Leaves of older G␤ mutant plants show much less cell death when infiltrated with Tm than leaves of wild-type plants. The transcriptional response of G␤ mutant plants to Tm is less pronounced than that of wild-type plants, as is the accumulation of BiP chaperone proteins. A majority of the Arabidopsis G␤ protein is associated with the endoplasmic reticulum (ER) and cofractionates with membrane-associated ER luminal BiP. Consistent with its ER localization, G␤ protein is degraded during the UPR, whereas G␣ protein is not. Taken together, these observations imply that the G␤ protein, which forms a stable heterodimer with the G␥ subunit, is involved in the signaling events that trigger UPR-associated cell death. The different Tm sensitivities of G␣ and G␤ mutants, the ER localization of G␤, and the differential stabilities of G␣ and G␤ proteins during the UPR suggest that the G␤␥ complex serves a signaling function in the ER independent of its function in the G␣␤␥ heterotrimer.endoplasmic reticulum ͉ tunicamycin

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Untitled

Cited by 20 publications

References 30 publications

Convergent energy and stress signaling

Convergent energy and stress signaling

Differential Phosphorylation of Plant Translation Initiation Factors by Arabidopsis thaliana CK2 Holoenzymes

Heterotrimeric G protein signaling in theArabidopsisunfolded protein response

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