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Publikationen - Molekulare Signalverarbeitung

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Publikation

Khalil, S.; Strah, R.; Lodovici, A.; Vojta, P.; Berardinis, F. D.; Ziegler, J.; Novak, M. P.; Zanin, L.; Tomasi, N.; Forneck, A.; Griesser, M.; The activation of iron deficiency responses of grapevine rootstocks is dependent to the availability of the nitrogen forms BMC Plant Biol. 24, 218, (2024) DOI: 10.1186/s12870-024-04906-y

Background  In viticulture, iron (Fe) chlorosis is a common abiotic stress that impairs plant development and leads to yield and quality losses. Under low availability of the metal, the applied N form (nitrate and ammonium) can play a role in promoting or mitigating Fe deficiency stresses. However, the processes involved are not clear in grapevine. Therefore, the aim of this study was to investigate the response of two grapevine rootstocks to the interaction between N forms and Fe uptake. This process was evaluated in a hydroponic experiment using two ungrafted grapevine rootstocks Fercal (Vitis berlandieri x V. vinifera) tolerant to deficiency induced Fe chlorosis and Couderc 3309 (V. riparia x V. rupestris) susceptible to deficiency induced Fe chlorosis. Results  The results could differentiate Fe deficiency effects, N-forms effects, and rootstock effects. Interveinal chlorosis of young leaves appeared earlier on 3309 C from the second week of treatment with NO3−/NH4+ (1:0)/-Fe, while Fercal leaves showed less severe symptoms after four weeks of treatment, corresponding to decreased chlorophyll concentrations lowered by 75% in 3309 C and 57% in Fercal. Ferric chelate reductase (FCR) activity was by trend enhanced under Fe deficiency in Fercal with both N combinations, whereas 3309 C showed an increase in FCR activity under Fe deficiency only with NO3−/NH4+ (1:1) treatment. With the transcriptome analysis, Gene Ontology (GO) revealed multiple biological processes and molecular functions that were significantly regulated in grapevine rootstocks under Fe-deficient conditions, with more genes regulated in Fercal responses, especially when both forms of N were supplied. Furthermore, the expression of genes involved in the auxin and abscisic acid metabolic pathways was markedly increased by the equal supply of both forms of N under Fe deficiency conditions. In addition, changes in the expression of genes related to Fe uptake, regulation, and transport reflected the different responses of the two grapevine rootstocks to different N forms. Conclusions  Results show a clear contribution of N forms to the response of the two grapevine rootstocks under Fe deficiency, highlighting the importance of providing both N forms (nitrate and ammonium) in an appropriate ratio in order to ease the rootstock responses to Fe deficiency.
Publikation

Terrile, M. C.; Tebez, N. M.; Colman, S. L.; Mateos, J. L.; Morato-López, E.; Sánchez-López, N.; Izquierdo-Álvarez, A.; Marina, A.; Calderón Villalobos, L. I. A.; Estelle, M.; Martínez-Ruiz, A.; Fiol, D. F.; Casalongué, C. A.; Iglesias, M. J.; S-Nitrosation of E3 ubiquitin ligase complex components regulates hormonal signalings in Arabidopsis Front. Plant Sci. 12, 794582, (2022) DOI: 10.3389/fpls.2021.794582

E3 ubiquitin ligases mediate the last step of the ubiquitination pathway in the ubiquitin-proteasome system (UPS). By targeting transcriptional regulators for their turnover, E3s play a crucial role in every aspect of plant biology. In plants, SKP1/CULLIN1/F-BOX PROTEIN (SCF)-type E3 ubiquitin ligases are essential for the perception and signaling of several key hormones including auxins and jasmonates (JAs). F-box proteins, TRANSPORT INHIBITOR RESPONSE 1 (TIR1) and CORONATINE INSENSITIVE 1 (COI1), bind directly transcriptional repressors AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) and JASMONATE ZIM-DOMAIN (JAZ) in auxin- and JAs-depending manner, respectively, which permits the perception of the hormones and transcriptional activation of signaling pathways. Redox modification of proteins mainly by S-nitrosation of cysteines (Cys) residues via nitric oxide (NO) has emerged as a valued regulatory mechanism in physiological processes requiring its rapid and versatile integration. Previously, we demonstrated that TIR1 and Arabidopsis thaliana SKP1 (ASK1) are targets of S-nitrosation, and these NO-dependent posttranslational modifications enhance protein-protein interactions and positively regulate SCFTIR1 complex assembly and expression of auxin response genes. In this work, we confirmed S-nitrosation of Cys140 in TIR1, which was associated in planta to auxin-dependent developmental and stress-associated responses. In addition, we provide evidence on the modulation of the SCFCOI1 complex by different S-nitrosation events. We demonstrated that S-nitrosation of ASK1 Cys118 enhanced ASK1-COI1 protein-protein interaction. Overexpression of non-nitrosable ask1 mutant protein impaired the activation of JA-responsive genes mediated by SCFCOI1 illustrating the functional relevance of this redox-mediated regulation in planta. In silico analysis positions COI1 as a promising S-nitrosation target, and demonstrated that plants treated with methyl JA (MeJA) or S-nitrosocysteine (NO-Cys, S-nitrosation agent) develop shared responses at a genome-wide level. The regulation of SCF components involved in hormonal perception by S-nitrosation may represent a key strategy to determine the precise time and site-dependent activation of each hormonal signaling pathway and highlights NO as a pivotal molecular player in these scenarios.
Preprints

Bassal, M.; Majovsky, P.; Thieme, D.; Herr, T.; Abukhalaf, M.; Ayash, M.; Al Shweiki, M. R.; Proksch, C.; Hmedat, A.; Ziegler, J.; Neumann, S.; Hoehenwarter, W.; Reshaping of the Arabidopsis thaliana proteome landscape and co-regulation of proteins in development and immunity bioRxiv (2020) DOI: 10.1101/2020.03.09.978627

Proteome remodeling is a fundamental adaptive response and proteins in complex and functionally related proteins are often co-expressed. Using a deep sampling strategy we define Arabidopsis thaliana tissue core proteomes at around 10,000 proteins per tissue and absolutely quantify (copy numbers per cell) nearly 16,000 proteins throughout the plant lifecycle. A proteome wide survey of global post translational modification revealed amino acid exchanges pointing to potential conservation of translational infidelity in eukaryotes. Correlation analysis of protein abundance uncovered potentially new tissue and age specific roles of entire signaling modules regulating transcription in photosynthesis, seed development and senescence and abscission. Among others, the data suggest a potential function of RD26 and other NAC transcription factors in seed development related to desiccation tolerance as well as a possible function of Cysteine-rich Receptor-like Kinases (CRKs) as ROS sensors in senescence. All of the components of ribosome biogenesis factor (RBF) complexes were co-expressed tissue and age specifically indicating functional promiscuity in the assembly of these little described protein complexes in Arabidopsis. Treatment of seedlings with flg22 for 16 hours allowed us to characterize proteome architecture in basal immunity in detail. The results were complemented with parallel reaction monitoring (PRM) targeted proteomics, phytohormone, amino acid and transcript measurements. We obtained strong evidence of suppression of jasmonate (JA) and JA-Ile levels by deconjugation and hydroxylation via IAA-ALA RESISTANT3 (IAR3) and JASMONATE-INDUCED OXYGENASE 2 (JOX2) under the control of JASMONATE INSENSITIVE 1 (MYC2). This previously unknown regulatory switch is another part of the puzzle of the as yet understudied role of JA in pattern triggered immunity. The extensive coverage of the Arabidopsis proteome in various biological scenarios presents a rich resource to plant biologists that we make available to the community.
Publikation

Bassal, M.; Abukhalaf, M.; Majovsky, P.; Thieme, D.; Herr, T.; Ayash, M.; Tabassum, N.; Al Shweiki, M. R.; Proksch, C.; Hmedat, A.; Ziegler, J.; Lee, J.; Neumann, S.; Hoehenwarter, W.; Reshaping of the Arabidopsis thaliana Proteome Landscape and Co-regulation of Proteins in Development and Immunity Mol. Plant 13, 1709-1732, (2020) DOI: 10.1016/j.molp.2020.09.024

Proteome remodeling is a fundamental adaptive response, and proteins in complexes and functionally related proteins are often co-expressed. Using a deep sampling strategy we define core proteomes of Arabidopsis thaliana tissues with around 10 000 proteins per tissue, and absolutely quantify (copy numbers per cell) nearly 16 000 proteins throughout the plant lifecycle. A proteome-wide survey of global post-translational modification revealed amino acid exchanges pointing to potential conservation of translational infidelity in eukaryotes. Correlation analysis of protein abundance uncovered potentially new tissue- and age-specific roles of entire signaling modules regulating transcription in photosynthesis, seed development, and senescence and abscission. Among others, the data suggest a potential function of RD26 and other NAC transcription factors in seed development related to desiccation tolerance as well as a possible function of cysteine-rich receptor-like kinases (CRKs) as ROS sensors in senescence. All of the components of ribosome biogenesis factor (RBF) complexes were found to be co-expressed in a tissue- and age-specific manner, indicating functional promiscuity in the assembly of these less-studied protein complexes in Arabidopsis. Furthermore, we characterized detailed proteome remodeling in basal immunity by treating Arabidopsis seeldings with flg22. Through simultaneously monitoring phytohormone and transcript changes upon flg22 treatment, we obtained strong evidence of suppression of jasmonate (JA) and JA-isoleucine (JA-Ile) levels by deconjugation and hydroxylation by IAA-ALA RESISTANT3 (IAR3) and JASMONATE-INDUCED OXYGENASE 2 (JOX2), respectively, under the control of JASMONATE INSENSITIVE 1 (MYC2), suggesting an unrecognized role of a new JA regulatory switch in pattern-triggered immunity. Taken together, the datasets generated in this study present extensive coverage of the Arabidopsis proteome in various biological scenarios, providing a rich resource available to the whole plant science community.
Publikation

Hussain, H.; Ziegler, J.; Mrestani, Y.; Neubert, R. H. H.; Studies of the Corneocytary Pathway Across the Stratum Corneum. Part I: Diffusion of Amino Acids Into the Isolated Corneocytes Pharmazie 74, 340-344, (2019) DOI: 10.1691/ph.2019.8098

Amino acids (AAs), important constituents of natural moisturizing factors (NMFs) of the skin are decreased in diseased conditions such as psoriasis and atopic dermatitis. No study so far investigated the uptake of AAs into isolated corneocytes (COR). The present study was performed using 19 AAs, including taurine (TAU), to measure their amount diffused into the COR and binding of these AAs to keratin. Incubation of alanine, aspartic acid, asparagine, glutamine, glutamic acid, histidine, proline, serine and TAU with the isolated COR showed uptake after 24 h of 51.6, 95.4, 98.6, 94.1, 95.6, 90.1, 94.6, 72.9 and 57.8 %, respectively, into the COR but no binding with keratin. Uptake of TAU was validated by time dependent in-vitro diffusion models 'without COR and 'with COR'. The time dependent curve fitting showed that in in-vitro diffusion model 'without COR' there was no change in the total concentration of TAU until 72 hours, while in diffusion model 'with COR' the total conc. decreased to 37.8 % after 72 hours. The Pearson's correlation coefficient 'r' between the conc. curves of both in-vitro diffusion models was -0.54 that was an evidence of significant amount of TAU uptake by the COR. AAs as part of the NMFs have a great potential to be diffused into the COR. This property of the AAs can be employed in further dermatological research on diseased or aged skin conditions with NMFs deficiency.
Publikation

Hussain, H.; Ziegler, J.; Hause, G.; Wohlrab, J.; Neubert, R. H.; Quantitative Analysis of Free Amino Acids and Urea Derived from Isolated Corneocytes of Healthy Young, Healthy Aged, and Diseased Skin Skin Pharmacol. Physiol. 32, 94-100, (2019) DOI: 10.1159/000495992

Background/Aims: Free amino acids (FAAs) and urea, present inside the corneocytes, can be important indicators of skin condition. However, due to the lack of a standard extraction protocol for FAAs from corneocytes, conflicting research results have been reported. Therefore, the purpose of this study was (1) to standardize the extraction protocol and (2) to investigate FAA profiles in healthy young and healthy old volunteers, as well as in psoriasis and atopic dermatitis patients. Methods: Skin samples were collected from four groups (healthy young, healthy old, and psoriasis and atopic dermatitis patients) with 5 volunteers per group. Corneocytes were isolated and examined microscopically. FAAs and urea were extracted from the isolated corneocytes, and their amounts were quantified using LC-ESI/MS/MS (after derivatization with Fmoc-Cl) and colorimetric methods, respectively. Results: The micrographs of the corneocytes showed no morphological features attributable to age or disease conditions. The highest and lowest concentrations of total FAAs and urea were observed in the healthy old group and the healthy young group, respectively. Unlike the other FAAs and urea, citrulline was found at a higher level in the healthy young group than in the disease groups. Conclusion: This study suggests that the levels of FAAs and urea in the skin are affected by age and skin conditions (healthy/diseased). However, further studies are needed to show the effects of different skin conditions on the levels of FAAs and urea.
Bücher und Buchkapitel

Ziegler, J.; Hussain, H.; Neubert, R. H. H.; Abel, S.; Sensitive and Selective Amino Acid Profiling of Minute Tissue Amounts by HPLC/Electrospray Negative Tandem Mass Spectrometry Using 9-Fluorenylmethoxycarbonyl (Fmoc-Cl) Derivatization (Alterman, M. A., ed.). Methods Mol. Biol. 2030, 365-379, (2019) ISBN: 978-1-4939-9639-1 DOI: 10.1007/978-1-4939-9639-1_27

A method for selective and sensitive quantification of amino acids is described. The combination of established derivatization procedures of secondary and primary amino groups with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) and subsequent detection of derivatized amino acids by LC-ESI-MS/MS using multiple reaction monitoring provides high selectivity. The attachment of an apolar moiety enables purification of derivatized amino acids from matrix by a single solid-phase extraction step, which increases sensitivity by reduced ion suppression during LC-ESI-MS/MS detection. Additionally, chromatography of all amino acids can be performed on reversed-phase HPLC columns using eluents without additives, which are known to cause significant decreases in signal to noise ratios. The method has been routinely applied for amino acid profiling of low amounts of liquids and tissues of various origins with a sample throughput of about 50–100 samples a day. In addition to a detailed description of the method, some representative examples are presented.
Publikation

Iglesias, M. J.; Terrile, M. C.; Correa-Aragunde, N.; Colman, S. L.; Izquierdo-Álvarez, A.; Fiol, D. F.; París, R.; Sánchez-López, N.; Marina, A.; Calderón Villalobos, L. I. A.; Estelle, M.; Lamattina, L.; Martínez-Ruiz, A.; Casalongué, C. A.; Regulation of SCFTIR1/AFBs E3 ligase assembly by S-nitrosylation of Arabidopsis SKP1-like1 impacts on auxin signaling Redox Biol. 18, 200-210, (2018) DOI: 10.1016/j.redox.2018.07.003

The F-box proteins (FBPs) TIR1/AFBs are the substrate recognition subunits of SKP1–cullin–F-box (SCF) ubiquitin ligase complexes and together with Aux/IAAs form the auxin co-receptor. Although tremendous knowledge on auxin perception and signaling has been gained in the last years, SCFTIR1/AFBs complex assembly and stabilization are emerging as new layers of regulation. Here, we investigated how nitric oxide (NO), through S-nitrosylation of ASK1 is involved in SCFTIR1/AFBs assembly. We demonstrate that ASK1 is S-nitrosylated and S-glutathionylated in cysteine (Cys) 37 and Cys118 residues in vitro. Both, in vitro and in vivo protein-protein interaction assays show that NO enhances ASK1 binding to CUL1 and TIR1/AFB2, required for SCFTIR1/AFB2 assembly. In addition, we demonstrate that Cys37 and Cys118 are essential residues for proper activation of auxin signaling pathway in planta. Phylogenetic analysis revealed that Cys37 residue is only conserved in SKP proteins in Angiosperms, suggesting that S-nitrosylation on Cys37 could represent an evolutionary adaption for SKP1 function in flowering plants. Collectively, these findings indicate that multiple events of redox modifications might be part of a fine-tuning regulation of SCFTIR1/AFBs for proper auxin signal transduction.
Publikation

Bochnia, M.; Scheidemann, W.; Ziegler, J.; Sander, J.; Vollstedt, S.; Glatter, M.; Janzen, N.; Terhardt, M.; Zeyner, A.; Predictive value of hypoglycin A and methylencyclopropylacetic acid conjugates in a horse with atypical myopathy in comparison to its cograzing partners Equine Vet. Educ. 30, 24-28, (2018) DOI: 10.1111/eve.12596

Hypoglycin A (HGA) was detected in blood and urine of a horse suffering from atypical myopathy (AM; Day 2, serum, 8290 μg/l; urine: Day 1, 574, Day 2, 742 μg/l) and in its cograzing partners with a high variability (46–1570 μg/l serum). Over the period of disease, the level of the toxic metabolites (methylencyclopropylacetic acid [MCPA]‐conjugates) increased in body fluids of the AM horse (MCPA‐carnitine: Day 2, 0.246, Day 3, 0.581 μmol/l serum; MCPA‐carnitine: Day 2, 0.621, Day 3, 0.884 μmol/mmol creatinine in urine) and HGA decreased rapidly (Day 3, 2430 μg/l serum). In cograzing horses MCPA‐conjugates were not detected. HGA in seeds ranged from 268 to 367 μg/g. Although HGA was present in body fluids of healthy cograzing horses, MCPA‐conjugates were not detectable, in contrast to the AM horse. Therefore, increasing concentrations of MCPA‐conjugates are supposed to be linked with the onset of AM and both parameters seem to indicate the clinical stage of disease. However, detection of HGA in body fluids of cograzing horses might be a promising step in preventing the disease.
Publikation

Bagchi, R.; Melnyk, C. W.; Christ, G.; Winkler, M.; Kirchsteiner, K.; Salehin, M.; Mergner, J.; Niemeyer, M.; Schwechheimer, C.; Calderón Villalobos, L. I. A.; Estelle, M.; The Arabidopsis ALF4 protein is a regulator of SCF E3 ligases EMBO J. 37, 255-268, (2018) DOI: 10.15252/embj.201797159

The cullin‐RING E3 ligases (CRLs) regulate diverse cellular processes in all eukaryotes. CRL activity is controlled by several proteins or protein complexes, including NEDD8, CAND1, and the CSN. Recently, a mammalian protein called Glomulin (GLMN) was shown to inhibit CRLs by binding to the RING BOX (RBX1) subunit and preventing binding to the ubiquitin‐conjugating enzyme. Here, we show that Arabidopsis ABERRANT LATERAL ROOT FORMATION4 (ALF4) is an ortholog of GLMN. The alf4 mutant exhibits a phenotype that suggests defects in plant hormone response. We show that ALF4 binds to RBX1 and inhibits the activity of SCFTIR1, an E3 ligase responsible for degradation of the Aux/IAA transcriptional repressors. In vivo, the alf4 mutation destabilizes the CUL1 subunit of the SCF. Reduced CUL1 levels are associated with increased levels of the Aux/IAA proteins as well as the DELLA repressors, substrate of SCFSLY1. We propose that the alf4 phenotype is partly due to increased levels of the Aux/IAA and DELLA proteins.
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