zur Suche springenzur Navigation springenzum Inhalt springen

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 1 bis 10 von 37.

Publikation

Dissmeyer, N.; Coux, O.; Rodriguez, M. S.; Barrio, R.; the Core Group Members of PROTEOSTASIS, .; PROTEOSTASIS: A European Network to Break Barriers and Integrate Science on Protein Homeostasis Trends Biochem. Sci. 44, 383-387, (2019) DOI: 10.1016/j.tibs.2019.01.007

Protein homeostasis (proteostasis) is at the core of cellular functions. The European network PROTEOSTASIS was created to steer research and foster collaborations in the interconnected fields of posttranslational modifications by ubiquitin family members and protein turnover by proteasome, autophagy, and lysosomal systems in health and diseases, across the kingdoms of life.
Publikation

Dissmeyer, N.; Conditional Protein Function via N-Degron Pathway–Mediated Proteostasis in Stress Physiology Annu. Rev. Plant Biol. 70, 83-117, (2019) DOI: 10.1146/annurev-arplant-050718-095937

The N-degron pathway, formerly the N-end rule pathway, regulates functions of regulatory proteins. It impacts protein half-life and therefore directs the actual presence of target proteins in the cell. The current concept holds that the N-degron pathway depends on the identity of the amino (N)-terminal amino acid and many other factors, such as the follow-up sequence at the N terminus, conformation, flexibility, and protein localization. It is evolutionarily conserved throughout the kingdoms. One possible entry point for substrates of the N-degron pathway is oxidation of N-terminal Cys residues. Oxidation of N-terminal Cys is decisive for further enzymatic modification of various neo–N termini by arginylation that generates potentially neofunctionalized or instable proteoforms. Here, I focus on the posttranslational modifications that are encompassed by protein degradation via the Cys/Arg branch of the N-degron pathway—part of the PROTEOLYSIS 6 (PRT6)/N-degron pathway—as well as the underlying physiological principles of this branch and its biological significance in stress response.
Publikation

Dissmeyer, N.; Graciet, E.; Holdsworth, M. J.; Gibbs, D. J.; N-term 2017: Proteostasis via the N-terminus Trends Biochem. Sci. 44, 293-295, (2019) DOI: 10.1016/j.tibs.2017.11.006

N-term 2017 was the first international meeting to bring together researchers from diverse disciplines with a shared interest in protein N-terminal modifications and the N-end rule pathway of ubiquitin-mediated proteolysis, providing a platform for interdisciplinary cross-kingdom discussions and collaborations, as well as strengthening the visibility of this growing scientific community.
Publikation

Bäumler, J.; Riber, W.; Klecker, M.; Müller, L.; Dissmeyer, N.; Weig, A. R.; Mustroph, A.; AtERF#111/ABR1 is a transcriptional activator involved in the wounding response Plant J. 100, 969-990, (2019) DOI: 10.1111/tpj.14490

AtERF#111/ABR1 belongs to the group X of the ERF/AP2 transcription factor family (GXERFs) and is shoot specifically induced under submergence and hypoxia. It was described to be an ABA‐response repressor, but our data reveal a completely different function. Surprisingly, AtERF#111 expression is strongly responsive to wounding stress. Expression profiling of ERF#111‐overexpressing (OE) plants, which show morphological phenotypes like increased root hair length and number, strengthens the hypothesis of AtERF#111 being involved in the wounding response, thereby acting as a transcriptional activator of gene expression. Consistent with a potential function outside of oxygen signalling, we could not assign AtERF#111 as a target of the PRT6 N‐degron pathway, even though it starts with a highly conserved N‐terminal Met−Cys (MC) motif. However, the protein is unstable as it is degraded in an ubiquitin‐dependent manner. Finally, direct target genes of AtERF#111 were identified by microarray analyses and subsequently confirmed by protoplast transactivation assays. The special roles of diverse members of the plant‐specific GXERFs in coordinating stress signalling and wound repair mechanisms have been recently hypothesized, and our data suggest that AtERF#111 is indeed involved in these processes.
Preprints

Faden, F.; Mielke, S.; Dissmeyer, N.; Switching toxic protein function in life cells bioRxiv (2018) DOI: 10.1101/430439

Toxic proteins are prime targets for molecular farming and efficient tools for targeted cell ablation in genetics, developmental biology, and biotechnology. Achieving conditional activity of cytotoxins and their maintenance in form of stably transformed transgenes is challenging. We demonstrate here a switchable version of the highly cytotoxic bacterial ribonuclease barnase by using efficient temperature-dependent control of protein accumulation in living multicellular organisms. By tuning the levels of the protein, we were able to control the fate of a plant organ in vivo. The on-demand-formation of specialized epidermal cells (trichomes) through manipulating stabilization versus destabilization of barnase is a proof-of-concept for a robust and powerful tool for conditional switchable cell arrest. We present this tool both as a potential novel strategy for the manufacture and accumulation of cytotoxic proteins and toxic high-value products in plants or for conditional genetic cell ablation.
Publikation

Mot, A. C.; Prell, E.; Klecker, M.; Naumann, C.; Faden, F.; Westermann, B.; Dissmeyer, N.; Real-time detection of N-end rule-mediated ubiquitination via fluorescently labeled substrate probes New Phytol. 217, 613-624, (2018) DOI: 10.1111/nph.14497

The N‐end rule pathway has emerged as a major system for regulating protein functions by controlling their turnover in medical, animal and plant sciences as well as agriculture. Although novel functions and enzymes of the pathway have been discovered, the ubiquitination mechanism and substrate specificity of N‐end rule pathway E3 ubiquitin ligases have remained elusive. Taking the first discovered bona fide plant N‐end rule E3 ligase PROTEOLYSIS1 (PRT1) as a model, we used a novel tool to molecularly characterize polyubiquitination live, in real time.We gained mechanistic insights into PRT1 substrate preference and activation by monitoring live ubiquitination using a fluorescent chemical probe coupled to artificial substrate reporters. Ubiquitination was measured by rapid in‐gel fluorescence scanning as well as in real time by fluorescence polarization.The enzymatic activity, substrate specificity, mechanisms and reaction optimization of PRT1‐mediated ubiquitination were investigated ad hoc instantaneously and with significantly reduced reagent consumption.We demonstrated that PRT1 is indeed an E3 ligase, which has been hypothesized for over two decades. These results demonstrate that PRT1 has the potential to be involved in polyubiquitination of various substrates and therefore pave the way to understanding recently discovered phenotypes of prt1 mutants.
Publikation

Havé, M.; Balliau, T.; Cottyn-Boitte, B.; Dérond, E.; Cueff, G.; Soulay, F.; Lornac, A.; Reichman, P.; Dissmeyer, N.; Avice, J.-C.; Gallois, P.; Rajjou, L.; Zivy, M.; Masclaux-Daubresse, C.; Increases in activity of proteasome and papain-like cysteine protease in Arabidopsis autophagy mutants: back-up compensatory effect or cell-death promoting effect? J. Exp. Bot. 69, 1369-1385, (2018) DOI: 10.1093/jxb/erx482

Autophagy is essential for protein degradation, nutrient recycling, and nitrogen remobilization. Autophagy is induced during leaf ageing and in response to nitrogen starvation, and is known to play a fundamental role in nutrient recycling for remobilization and seed filling. Accordingly, ageing leaves of Arabidopsis autophagy mutants (atg) have been shown to over-accumulate proteins and peptides, possibly because of a reduced protein degradation capacity. Surprisingly, atg leaves also displayed higher protease activities. The work reported here aimed at identifying the nature of the proteases and protease activities that accumulated differentially (higher or lower) in the atg mutants. Protease identification was performed using shotgun LC-MS/MS proteome analyses and activity-based protein profiling (ABPP). The results showed that the chloroplast FTSH (FILAMENTATION TEMPERATURE SENSITIVE H) and DEG (DEGRADATION OF PERIPLASMIC PROTEINS) proteases and several extracellular serine proteases [subtilases (SBTs) and serine carboxypeptidase-like (SCPL) proteases] were less abundant in atg5 mutants. By contrast, proteasome-related proteins and cytosolic or vacuole cysteine proteases were more abundant in atg5 mutants. Rubisco degradation assays and ABPP showed that the activities of proteasome and papain-like cysteine protease were increased in atg5 mutants. Whether these proteases play a back-up role in nutrient recycling and remobilization in atg mutants or act to promote cell death is discussed in relation to their accumulation patterns in the atg5 mutant compared with the salicylic acid-depleted atg5/sid2 double-mutant, and in low nitrate compared with high nitrate conditions. Several of the proteins identified are indeed known as senescence- and stress-related proteases or as spontaneous cell-death triggering factors.
Preprints

Dissmeyer, N.; Rivas, S.; Graciet, E.; Life and death of proteins after protease cleavage: protein degradation by the N-end rule pathway bioRxiv (2017) DOI: 10.1101/115246

The activity and abundance of proteins within a cell are controlled precisely to ensure the regulation of cellular and physiological processes. In eukaryotes, this can be achieved by targeting specific proteins for degradation by the ubiquitinproteasome system. The N-end rule pathway, a subset of the ubiquitinproteasome system, targets proteins for degradation depending on the identity of a protein N-terminal residue or its post-translational modifications. Here, we discuss the most recent findings on the diversity of N-end rule pathways. We also focus on recently found defensive functions of the N-end rule pathway in plants. We then discuss the current understanding of N-end rule substrate formation by protease cleavage. Finally, we review state-of-the-art proteomics techniques used for N-end rule substrate identification, and discuss their usefulness and limitations for the discovery of the molecular mechanisms underlying the roles of the N-end rule pathway in plants.
Publikation

White, M. D.; Klecker, M.; Hopkinson, R. J.; Weits, D. A.; Mueller, C.; Naumann, C.; O’Neill, R.; Wickens, J.; Yang, J.; Brooks-Bartlett, J. C.; Garman, E. F.; Grossmann, T. N.; Dissmeyer, N.; Flashman, E.; Plant cysteine oxidases are dioxygenases that directly enable arginyl transferase-catalysed arginylation of N-end rule targets Nat. Commun. 8, 14690, (2017) DOI: 10.1038/ncomms14690

Crop yield loss due to flooding is a threat to food security. Submergence-induced hypoxia in plants results in stabilization of group VII ETHYLENE RESPONSE FACTORs (ERF-VIIs), which aid survival under these adverse conditions. ERF-VII stability is controlled by the N-end rule pathway, which proposes that ERF-VII N-terminal cysteine oxidation in normoxia enables arginylation followed by proteasomal degradation. The PLANT CYSTEINE OXIDASEs (PCOs) have been identified as catalysts of this oxidation. ERF-VII stabilization in hypoxia presumably arises from reduced PCO activity. We directly demonstrate that PCO dioxygenase activity produces Cys-sulfinic acid at the N terminus of an ERF-VII peptide, which then undergoes efficient arginylation by an arginyl transferase (ATE1). This provides molecular evidence of N-terminal Cys-sulfinic acid formation and arginylation by N-end rule pathway components, and a substrate of ATE1 in plants. The PCOs and ATE1 may be viable intervention targets to stabilize N-end rule substrates, including ERF-VIIs, to enhance submergence tolerance in agriculture.
Publikation

Dong, H.; Dumenil, J.; Lu, F.-H.; Na, L.; Vanhaeren, H.; Naumann, C.; Klecker, M.; Prior, R.; Smith, C.; McKenzie, N.; Saalbach, G.; Chen, L.; Xia, T.; Gonzalez, N.; Seguela, M.; Inze, D.; Dissmeyer, N.; Li, Y.; Bevan, M. W.; Ubiquitylation activates a peptidase that promotes cleavage and destabilization of its activating E3 ligases and diverse growth regulatory proteins to limit cell proliferation in Arabidopsis Genes Dev. 31, 197-208, (2017) DOI: 10.1101/gad.292235.116

The characteristic shapes and sizes of organs are established by cell proliferation patterns and final cell sizes, but the underlying molecular mechanisms coordinating these are poorly understood. Here we characterize a ubiquitin-activated peptidase called DA1 that limits the duration of cell proliferation during organ growth in Arabidopsis thaliana. The peptidase is activated by two RING E3 ligases, Big Brother (BB) and DA2, which are subsequently cleaved by the activated peptidase and destabilized. In the case of BB, cleavage leads to destabilization by the RING E3 ligase PROTEOLYSIS 1 (PRT1) of the N-end rule pathway. DA1 peptidase activity also cleaves the deubiquitylase UBP15, which promotes cell proliferation, and the transcription factors TEOSINTE BRANCED 1/CYCLOIDEA/PCF 15 (TCP15) and TCP22, which promote cell proliferation and repress endoreduplication. We propose that DA1 peptidase activity regulates the duration of cell proliferation and the transition to endoreduplication and differentiation during organ formation in plants by coordinating the destabilization of regulatory proteins.
IPB Mainnav Search