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Proteome Analytics

The spatio-temporal remodeling of the proteome, the cellular complement of all proteoforms, is a primary phenotype determinant. As such we are interested in quantifying protein expression dynamics, i.e. the changing abundance, subcellular localization, post translational modification and interaction of proteins in various biological scenarios. It is our goal to gain an understanding of the intricate mechanisms of plant proteome biology.

Fig.1 and 2. Cutting edge mass spectrometry is used to measure peptides and proteins.
Fig.1 and 2. Cutting edge mass spectrometry is used to measure peptides and proteins.

Recently our research group has streamlined and optimized the discovery proteomics approach and adapted it to plants. This technology now allows us to routinely quantify from 6,000 to 9,000 proteins (protein groups) per tissue sample with at least one unique peptide and a peptide and protein FDR threshold of 1%.

A primary research interest of the group is the effects of phytohormones in biotic and abiotic stress adaption. We are applying the deep proteomics strategy in combination with metabolomics and targeted proteomics measurements to shed more light on the interplay of the canonical defense phytohormones salicylic acid, jasmonate and ethylene but also on the role of auxin in the hormone signal signature in reshaping the proteome to resist pathogen attack.

Deep proteomics measurements of various tissues throughout plant development led to date to the accumulation of mass spectrometric evidence of nearly 16,000 protein coding genes which is about 60% of Arabidopsis thaliana open reading frames. This extensive coverage of the Arabidopsis genome is being used to investigate proteome wide correlation of protein abundance in different tissues as well as correlated local protein expression of genes in smaller and larger neighborhoods.

Fig. 3. Deep coverage of the Arabidopsis thaliana proteome
Fig. 3. Deep coverage of the Arabidopsis thaliana proteome

Targeted proteomics approaches are also well established in the group as a complement to discovery proteomics. These were particularly advanced by accurate measurement of fragment ion masses with the QExactive Plus mass spectrometer. This allows interpretation of MS/MS spectra and assignment of PTMs to peptide primary structure with low error probability. Reversible, multi-site PTM has as much an impact on protein function as translation of the nascent polypeptide itself. Numerous directed and undirected proteomics studies that quantify site-specific protein PTM are being performed with a growing interest in histone modification and epigenetics.

Equipment and Instrumentation

 

Mass Spectrometry

  • Orbitrap Velos Pro (Thermo Scientific)
  • QExactive Plus (Thermo Scientific)

 

HPLC

  • EASY-nLC II (Thermo Scientific)
  • EASY-nLC 1000 (Thermo Scientific)
  • Ultimate 3000 (Thermo Scientific)

 

Software

  • Mascot v.2.5
  • Mascot Distiller
  • SEQUEST
  • Proteome Discoverer v.1.4
  • Progenesis QIP
  • Scaffold 4 / Scaffold PTM 2 Image Quant TL
  • Skyline
  • MaxQuant
  • Perseus
  • MapMan

The Team

Dr. Wolfgang Hoehenwarter

Staff Member
Abukhalaf, Mohammad Master Student
Herr, Tobias Research Assistant
Proksch, Carsten Technician
Thieme, Domenika Technician

Publications by Tag: Proteomics

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Displaying results 1 to 10 of 47.

Publications

Chen, Y.; Hoehenwarter, W. Rapid and reproducible phosphopeptide enrichment by tandem metal oxide affinity chromatography: application to boron deficiency induced phosphoproteomics Plant J 98, 370-384, (2019) DOI: 10.1111/tpj.14215

Mass spectrometry has been instrumental in enabling the study of molecular signaling on a cellular scale by way of site‐specific quantification of protein post‐translational modifications, in particular phosphorylation. Here we describe an updated tandem metal oxide affinity chromatography (MOAC) combined phosphoprotein/phosphopeptide enrichment strategy, a scalable phosphoproteomics approach that allows rapid identification of thousands of phosphopeptides in plant materials. We implemented modifications to several steps of the original tandem MOAC procedure to increase the amount of quantified phosphopeptides and hence site‐specific phosphorylation of proteins in a sample beginning with the less amounts of tissue and a substantially smaller amount of extracted protein. We applied this technology to generate time‐resolved maps of boron signaling in Arabidopsis roots. We show that the successive enrichment of phosphoproteins in a first and phosphopeptide extraction in a second step using our optimized procedure strongly enriched the root phosphoproteome. Our results reveal that boron deficiency affects over 20% of the measured root phosphoproteome and that many phosphorylation sites with known biological function, and an even larger number of previously undescribed sites, are modified during the time course of boron deficiency. We identify transcription factors as key regulators of hormone signaling pathways that modulate gene expression in boron deprived plants. Furthermore, our phosphorylation kinetics data demonstrate that mitogen‐activated protein kinase (MAPK) cascades mediate polarized transport of boron in Arabidopsis roots. Taken together, we establish and validate a robust approach for proteome‐wide phosphorylation analysis in plant biology research.
Publications

Mamontova, T.; Lukasheva, E.; Mavropolo-Stolyarenko, G.; Proksch, C.; Bilova, T.; Kim, A.; Babakov, V.; Grishina, T.; Hoehenwarter, W.; Medvedev, S.; Smolikova, G.; Frolov, A. Proteome Map of Pea (Pisum sativum L.) Embryos Containing Different Amounts of Residual Chlorophylls Int J Mol Sci 19, 4066, (2018) DOI: 10.3390/ijms19124066

Due to low culturing costs and high seed protein contents, legumes represent the main global source of food protein. Pea (Pisum sativum L.) is one of the major legume crops, impacting both animal feed and human nutrition. Therefore, the quality of pea seeds needs to be ensured in the context of sustainable crop production and nutritional efficiency. Apparently, changes in seed protein patterns might directly affect both of these aspects. Thus, here, we address the pea seed proteome in detail and provide, to the best of our knowledge, the most comprehensive annotation of the functions and intracellular localization of pea seed proteins. To address possible intercultivar differences, we compared seed proteomes of yellow- and green-seeded pea cultivars in a comprehensive case study. The analysis revealed totally 1938 and 1989 nonredundant proteins, respectively. Only 35 and 44 proteins, respectively, could be additionally identified after protamine sulfate precipitation (PSP), potentially indicating the high efficiency of our experimental workflow. Totally 981 protein groups were assigned to 34 functional classes, which were to a large extent differentially represented in yellow and green seeds. Closer analysis of these differences by processing of the data in KEGG and String databases revealed their possible relation to a higher metabolic status and reduced longevity of green seeds.
Publications

Schräder, C. U.; Heinz, A.; Majovsky, P.; Karaman Mayack, B.; Brinckmann, J.; Sippl, W.; Schmelzer, C. E. H. Elastin is heterogeneously cross-linked J Biol Chem 293, 15107-15119, (2018) DOI: 10.1074/jbc.RA118.004322

Elastin is an essential vertebrate protein responsible for the elasticity of force-bearing tissues such as those of the lungs, blood vessels, and skin. One of the key features required for the exceptional properties of this durable biopolymer is the extensive covalent cross-linking between domains of its monomer molecule tropoelastin. To date, elastin’s exact molecular assembly and mechanical properties are poorly understood. Here, using bovine elastin, we investigated the different types of cross-links in mature elastin to gain insight into its structure. We purified and proteolytically cleaved elastin from a single tissue sample into soluble cross-linked and non-cross-linked peptides that we studied by high-resolution MS. This analysis enabled the elucidation of cross-links and other elastin modifications. We found that the lysine residues within the tropoelastin sequence were simultaneously unmodified and involved in various types of cross-links with different other domains. The Lys-Pro domains were almost exclusively linked via lysinonorleucine, whereas Lys-Ala domains were found to be cross-linked via lysinonorleucine, allysine aldol, and desmosine. Unexpectedly, we identified a high number of intramolecular cross-links between lysine residues in close proximity. In summary, we show on the molecular level that elastin formation involves random cross-linking of tropoelastin monomers resulting in an unordered network, an unexpected finding compared with previous assumptions of an overall beaded structure.
Printed publications

Teh, O.-K.; Lee, C.-W.; Ditengou, F. A.; Klecker, T.; Furlan, G.; Zietz, M.; Hause, G.; Eschen-Lippold, L.; Hoehenwarter, W.; Lee, J.; Ott, T.; Trujillo, M. Phosphorylation of the exocyst subunit Exo70B2 contributes to the regulation of its function BioRxiv (2018) DOI: 10.1101/266171

The exocyst is a conserved hetero-octameric complex mediating early tethering during exocytosis. Its Exo70 subunit plays a critical role as a spatiotemporal regulator by mediating numerous protein and lipid interactions. However, a molecular understanding of the exocyst function remains challenging. We show that Exo70B2 locates to dynamic foci at the plasma membrane and transits through a BFA-sensitive compartment, reflecting its canonical function in secretion. However, treatment with the salicylic acid (SA) defence hormone analogue Benzothiadiazole (BTH), or the immunogenic peptide flg22, induced Exo70B2 transport into the vacuole. We uncovered two ATG8-interacting motifs (AIMs) located in the C-terminal domain (C-domain) of Exo70B2 that mediate its recruitment into the vacuole. Moreover, we also show that Exo70B2 is phosphorylated near the AIMs and mimicking phosphorylation enhanced ATG8 interaction. Finally, Exo70B2 phosphonull lines were hypersensitive to BTH and more resistant to avirulent bacteria which induce SA production. Our results suggests a molecular mechanism in which phosphorylation of Exo70B2 by MPK3 functions in a feed-back system linking cellular signalling to the secretory pathway.
Publications

Frolov, A.; Didio, A.; Ihling, C.; Chantzeva, V.; Grishina, T.; Hoehenwarter, W.; Sinz, A.; Smolikova, G.; Bilova, T.; Medvedev, S. The effect of simulated microgravity on the Brassica napus seedling proteome. Funct Plant Biol 45, 440-452, (2018) DOI: 10.1071/FP16378

The magnitude and the direction of the gravitational field represent an important environmental factor affecting plant development. In this context, the absence or frequent alterations of the gravity field (i.e. microgravity conditions) might compromise extraterrestrial agriculture and hence space inhabitation by humans. To overcome the deleterious effects of microgravity, a complete understanding of the underlying changes on the macromolecular level is necessary. However, although microgravity-related changes in gene expression are well characterised on the transcriptome level, proteomic data are limited. Moreover, information about the microgravity-induced changes in the seedling proteome during seed germination and the first steps of seedling development is completely missing. One of the valuable tools to assess gravity-related issues is 3D clinorotation (i.e. rotation in two axes). Therefore, here we address the effects of microgravity, simulated by a two-axial clinostat, on the proteome of 24- and 48-h-old seedlings of oilseed rape (Brassica napus L.). The liquid chromatography-MS-based proteomic analysis and database search revealed 95 up- and 38 downregulated proteins in the tryptic digests obtained from the seedlings subjected to simulated microgravity, with 42 and 52 annotations detected as being unique for 24- and 48-h treatment times, respectively. The polypeptides involved in protein metabolism, transport and signalling were annotated as the functional groups most strongly affected by 3-D clinorotation. 
Publications

Kowarschik, K.; Hoehenwarter, W.; Marillonnet, S.; Trujillo, M. UbiGate: a synthetic biology toolbox to analyse ubiquitination. New Phytol. 217, 1749-1763, (2018) DOI: 10.1111/nph.14900

   Ubiquitination is mediated by an enzymatic cascade that results in the modification of substrate proteins, redefining their fate. This post-translational modification is involved in most cellular processes, yet its analysis faces manifold obstacles due to its complex and ubiquitous nature. Reconstitution of the ubiquitination cascade in bacterial systems circumvents several of these problems and was shown to faithfully recapitulate the process.    Here, we present UbiGate − a synthetic biology toolbox, together with an inducible bacterial expression system – to enable the straightforward reconstitution of the ubiquitination cascades of different organisms in Escherichia coli by ‘Golden Gate’ cloning.    This inclusive toolbox uses a hierarchical modular cloning system to assemble complex DNA molecules encoding the multiple genetic elements of the ubiquitination cascade in a predefined order, to generate polycistronic operons for expression.    We demonstrate the efficiency of UbiGate in generating a variety of expression elements to reconstitute autoubiquitination by different E3 ligases and the modification of their substrates, as well as its usefulness for dissecting the process in a time- and cost-effective manner.
Publications

Mora Huertas, A. C.; Schmelzer, C. E. H.; Luise, C.; Sippl, W.; Pietzsch, M.; Hoehenwarter, W.; Heinz, A. Degradation of tropoelastin and skin elastin by neprilysin Biochimie 146, 73-78, (2018) DOI: 10.1016/j.biochi.2017.11.018

Neprilysin is also known as skin fibroblast-derived elastase, and its up-regulation during aging is associated with impairments of the elastic fiber network, loss of skin elasticity and wrinkle formation. However, information on its elastase activity is still limited. The aim of this study was to investigate the degradation of fibrillar skin elastin by neprilysin and the influence of the donor's age on the degradation process using mass spectrometry and bioinformatics approaches. The results showed that cleavage by neprilysin is dependent on previous damage of elastin. While neprilysin does not cleave young and intact skin elastin well, it degrades elastin fibers from older donors, which may further promote aging processes. With regards to the cleavage behavior of neprilysin, a strong preference for Gly at P1 was found, while Gly, Ala and Val were well accepted at P1′ upon cleavage of tropoelastin and skin elastin. The results of the study indicate that the progressive release of bioactive elastin peptides by neprilysin upon skin aging may enhance local tissue damage and accelerate extracellular matrix aging processes.
Publications

Frolov, A.; Mamontova, T.; Ihling, C.; Lukasheva, E.; Bankin, M.; Chantseva, V.; Vikhnina, M.; Soboleva, A.; Shumilina, J.; Mavropolo-Stolyarenko, G.; Grishina, T.; Osmolovskaya, N.; Zhukov, V.; Hoehenwarter, W.; Sinz, A.; Tikhononovich, I.; Wessjohann, L.; Bilova, T.; Smolikova, G.; Medvedev, S. Mining seed proteome: from protein dynamics to modification profiles Biol Commun 63, 43-58, (2018) DOI: 10.21638/spbu03.2018.106

In the modern world, crop plants represent a major source of daily consumed foods. Among them, cereals and legumes — i.e. the crops accumulating oils, carbohydrates and proteins in their seeds — dominate in European agriculture, tremendously impacting global protein consumption and biodiesel production. Therefore, the seeds of crop plants attract the special attention of biologists, biochemists, nutritional physiologists and food chemists. Seed development and germination, as well as age- and stress-related changes in their viability and nutritional properties, can be addressed by a variety of physiological and biochemical methods. In this context, the methods of functional genomics can be applied to address characteristic changes in seed metabolism, which can give access to stress-resistant genotypes. Among these methods, proteomics is one of the most effective tools, allowing mining metabolism changes on the protein level. Here we discuss the main methodological approaches of seed proteomics in the context of physiological changes related to environmental stress and ageing. We provide a comprehensive comparison of gel- and chromatographybased approaches with a special emphasis on advantages and disadvantages of both strategies in characterization of the seed proteome.
Publications

Hempel, F.; Stenzel, I.; Heilmann, M.; Krishnamoorthy, P.; Menzel, W.; Golbik, R.; Helm, S.; Dobritzsch, D.; Baginsky, S.; Lee, J.; Hoehenwarter, W.; Heilmann, I. MAPKs influence pollen tube growth by controlling the formation of Phosphatidylinositol 4,5-Bisphosphate in an apical plasma membrane domain.  Plant Cell 29, 3030-3050, (2017) DOI: 10.1105/tpc.17.00543

An apical plasma membrane domain enriched in the regulatory phospholipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] is critical for polar tip growth of pollen tubes. How the biosynthesis of PtdIns(4,5)P2 by phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) is controlled by upstream signaling is currently unknown. The pollen-expressed PI4P 5-kinase PIP5K6 is required for clathrin-mediated endocytosis and polar tip growth in pollen tubes. Here, we identify PIP5K6 as a target of the pollen-expressed mitogen-activated protein kinase MPK6 and characterize the regulatory effects. Based on an untargeted mass spectrometry approach, phosphorylation of purified recombinant PIP5K6 by pollen tube extracts could be attributed to MPK6. Recombinant MPK6 phosphorylated residues T590 and T597 in the variable insert of the catalytic domain of PIP5K6, and this modification inhibited PIP5K6 activity in vitro. PIP5K6 interacted with MPK6 in yeast two-hybrid tests, immuno-pull-down assays, and by bimolecular fluorescence complementation at the apical plasma membrane of pollen tubes. In vivo, MPK6 expression resulted in reduced plasma membrane association of a fluorescent PtdIns(4,5)P2 reporter and decreased endocytosis without impairing membrane association of PIP5K6. Effects of PIP5K6 expression on pollen tube growth and cell morphology were attenuated by coexpression of MPK6 in a phosphosite-dependent manner. Our data indicate that MPK6 controls PtdIns(4,5)P2 production and membrane trafficking in pollen tubes, possibly contributing to directional growth.
Publications

Winkler, M.; Niemeyer, M.; Hellmuth, A.; Janitza, P.; Christ, G.; Samodelov, S. L.; Wilde, V.; Majovsky, P.; Trujillo, M.; Zurbriggen, M. D.; Hoehenwarter, W.; Quint, M.; Calderón Villalobos, L. I. A. Variation in auxin sensing guides AUX/IAA transcriptional repressor ubiquitylation and destruction. Nature Commun. 8, 15706, (2017) DOI: 10.1038/ncomms15706

Auxin is a small molecule morphogen that bridges SCFTIR1/AFB-AUX/IAA co-receptor interactions leading to ubiquitylation and proteasome-dependent degradation of AUX/IAA transcriptional repressors. Here, we systematically dissect auxin sensing by SCFTIR1-IAA6 and SCFTIR1-IAA19 co-receptor complexes, and assess IAA6/IAA19 ubiquitylation in vitro and IAA6/IAA19 degradation in vivo. We show that TIR1-IAA19 and TIR1-IAA6 have distinct auxin affinities that correlate with ubiquitylation and turnover dynamics of the AUX/IAA. We establish a system to track AUX/IAA ubiquitylation in IAA6 and IAA19 in vitro and show that it occurs in flexible hotspots in degron-flanking regions adorned with specific Lys residues. We propose that this signature is exploited during auxin-mediated SCFTIR1-AUX/IAA interactions. We present evidence for an evolving AUX/IAA repertoire, typified by the IAA6/IAA19 ohnologues, that discriminates the range of auxin concentrations found in plants. We postulate that the intrinsic flexibility of AUX/IAAs might bias their ubiquitylation and destruction kinetics enabling specific auxin responses.

This page was last modified on 14.11.2018.

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