Examinando por Autor "Schulten, Anna"

Mostrando 1 - 2 de 2

Energy status-promoted growth and development of Arabidopsis require copper deficiency response transcriptional regulator SPL7
(Oxford University Press, 2022-07-22) Schulten, Anna; Pietzenuk, Bjoern; Quintana, Julia; Scholle, Marleen; Feil, Regina; Krause, Markus; Romera-Branchat, Maida; Wahl, Vanessa; Severing, Edouard; Coupland, George; Kraemer, Ute
Copper (Cu) is a cofactor of around 300 Arabidopsis proteins, including photosynthetic and mitochondrial electron transfer chain enzymes critical for adenosine triphosphate (ATP) production and carbon fixation. Plant acclimation to Cu deficiency requires the transcription factor SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 (SPL7). We report that in the wild type (WT) and in the spl7-1 mutant, respiratory electron flux via Cu-dependent cytochrome c oxidase is unaffected under both normal and low-Cu cultivation conditions. Supplementing Cu-deficient medium with exogenous sugar stimulated growth of the WT, but not of spl7 mutants. Instead, these mutants accumulated carbohydrates, including the signaling sugar trehalose 6-phosphate, as well as ATP and NADH, even under normal Cu supply and without sugar supplementation. Delayed spl7-1 development was in agreement with its attenuated sugar responsiveness. Functional TARGET OF RAPAMYCIN and SNF1-RELATED KINASE1 signaling in spl7-1 argued against fundamental defects in these energy-signaling hubs. Sequencing of chromatin immunoprecipitates combined with transcriptome profiling identified direct targets of SPL7-mediated positive regulation, including Fe SUPEROXIDE DISMUTASE1 (FSD1), COPPER-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR1 (CITF1), and the uncharacterized bHLH23 (CITF2), as well as an enriched upstream GTACTRC motif. In summary, transducing energy availability into growth and reproductive development requires the function of SPL7. Our results could help increase crop yields, especially on Cu-deficient soils.
Translational fidelity and growth of Arabidopsis require stress-sensitive diphthamide biosynthesis
(Springer Nature, 2022) Zhang, Hongliang; Quintana, Julia; Ütkür, Koray; Adrian, Lorenz; Hawer, Harmen; Mayer, Klaus; Gong, Xiaodi; Castanedo, Leonardo; Schulten, Anna; Janina, Nadežda; Peters, Marcus; Wirtz, Markus; Brinkmann, Ulrich; Schaffrath, Raffael; Kraemer, Ute
Diphthamide, a post-translationally modified histidine residue of eukaryotic TRANSLATION ELONGATION FACTOR2 (eEF2), is the human host cell-sensitizing target of diphtheria toxin. Diphthamide biosynthesis depends on the 4Fe-4S-cluster protein Dph1 catalyzing the first committed step, as well as Dph2 to Dph7, in yeast and mammals. Here we show that diphthamide modification of eEF2 is conserved in Arabidopsis thaliana and requires AtDPH1. Ribosomal −1 frameshifting-error rates are increased in Arabidopsis dph1 mutants, similar to yeast and mice. Compared to the wild type, shorter roots and smaller rosettes of dph1 mutants result from fewer formed cells. TARGET OF RAPAMYCIN (TOR) kinase activity is attenuated, and autophagy is activated, in dph1 mutants. Under abiotic stress diphthamide-unmodified eEF2 accumulates in wild-type seedlings, most strongly upon heavy metal excess, which is conserved in human cells. In summary, our results suggest that diphthamide contributes to the functionality of the translational machinery monitored by plants to regulate growth. Diphthamide is a post-translationally modified histidine residue present in animal and yeast TRANSLATION ELONGATION FACTOR2. Here the authors show that diphthamide modification of eEF2 is conserved in Arabidopsis thaliana and contributes to translational fidelity and growth via cell proliferation.