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Publikationen - Molekulare Signalverarbeitung

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Publikation

Nishiyama, T.; Sakayama, H.; de Vries, J.; Buschmann, H.; Saint-Marcoux, D.; Ullrich, K. K.; Haas, F. B.; Vanderstraeten, L.; Becker, D.; Lang, D.; Vosolsobě, S.; Rombauts, S.; Wilhelmsson, P. K.; Janitza, P.; Kern, R.; Heyl, A.; Rümpler, F.; Calderón Villalobos, L. I. A.; Clay, J. M.; Skokan, R.; Toyoda, A.; Suzuki, Y.; Kagoshima, H.; Schijlen, E.; Tajeshwar, N.; Catarino, B.; Hetherington, A. J.; Saltykova, A.; Bonnot, C.; Breuninger, H.; Symeonidi, A.; Radhakrishnan, G. V.; Van Nieuwerburgh, F.; Deforce, D.; Chang, C.; Karol, K. G.; Hedrich, R.; Ulvskov, P.; Glöckner, G.; Delwiche, C. F.; Petrášek, J.; Van de Peer, Y.; Friml, J.; Beilby, M.; Dolan, L.; Kohara, Y.; Sugano, S.; Fujiyama, A.; Delaux, P.-M.; Quint, M.; Theißen, G.; Hagemann, M.; Harholt, J.; Dunand, C.; Zachgo, S.; Langdale, J.; Maumus, F.; Van Der Straeten, D.; Gould, S. B.; Rensing, S. A.; The Chara Genome: Secondary Complexity and Implications for Plant Terrestrialization Cell 174, 448-464.e24, (2018) DOI: 10.1016/j.cell.2018.06.033

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via land-plant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.
Publikation

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 Nat. 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.
Publikation

Dinesh, D. C.; Calderón Villalobos, L. I. A.; Abel, S.; Structural Biology of Nuclear Auxin Action Trends Plant Sci. 21, 302-316, (2016) DOI: 10.1016/j.tplants.2015.10.019

Auxin coordinates plant development largely via hierarchical control of gene expression. During the past decades, the study of early auxin genes paired with the power of Arabidopsis genetics have unraveled key nuclear components and molecular interactions that perceive the hormone and activate primary response genes. Recent research in the realm of structural biology allowed unprecedented insight into: (i) the recognition of auxin-responsive DNA elements by auxin transcription factors; (ii) the inactivation of those auxin response factors by early auxin-inducible repressors; and (iii) the activation of target genes by auxin-triggered repressor degradation. The biophysical studies reviewed here provide an impetus for elucidating the molecular determinants of the intricate interactions between core components of the nuclear auxin response module.
Publikation

Delker, C.; Sonntag, L.; James, G.; Janitza, P.; Ibañez, C.; Ziermann, H.; Peterson, T.; Denk, K.; Mull, S.; Ziegler, J.; Davis, S.; Schneeberger, K.; Quint, M.; The DET1-COP1-HY5 Pathway Constitutes a Multipurpose Signaling Module Regulating Plant Photomorphogenesis and Thermomorphogenesis Cell Rep. 9, 1983-1989, (2014) DOI: 10.1016/j.celrep.2014.11.043

Developmental plasticity enables plants to respond to elevated ambient temperatures by adapting their shoot architecture. On the cellular level, the basic-helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4) coordinates this response by activating hormonal modules that in turn regulate growth. In addition to an unknown temperature-sensing mechanism, it is currently not understood how temperature regulates PIF4 activity. Using a forward genetic approach in Arabidopsis thaliana, we present extensive genetic evidence demonstrating that the DE-ETIOLATED 1 (DET1)-CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1)-ELONGATED HYPOCOTYL 5 (HY5)-dependent photomorphogenesis pathway transcriptionally regulates PIF4 to coordinate seedling growth in response to elevated temperature. Our findings demonstrate that two of the most prevalent environmental cues, light and temperature, share a much larger set of signaling components than previously assumed. Similar to the toolbox concept in animal embryonic patterning, multipurpose signaling modules might have evolved in plants to translate various environmental stimuli into adaptational growth processes.
Publikation

Janitza, P.; Ullrich, K. K.; Quint, M.; Toward a comprehensive phylogenetic reconstruction of the evolutionary history of mitogen-activated protein kinases in the plant kingdom Front. Plant Sci. 3, 271, (2012) DOI: 10.3389/fpls.2012.00271

The mitogen-activated protein kinase (MAPK) pathway is a three-tier signaling cascade that transmits cellular information from the plasma membrane to the cytoplasm where it triggers downstream responses. The MAPKs represent the last step in this cascade and are activated when both tyrosine and threonine residues in a conserved TxY motif are phosphorylated by MAPK kinases, which in turn are themselves activated by phosphorylation by MAPK kinase kinases. To understand the molecular evolution of MAPKs in the plant kingdom, we systematically conducted a Hidden-Markov-Model based screen to identify MAPKs in 13 completely sequenced plant genomes. In this analysis, we included green algae, bryophytes, lycophytes, and several mono- and eudicotyledonous species covering >800 million years of evolution. The phylogenetic relationships of the 204 identified MAPKs based on Bayesian inference facilitated the retraction of the sequence of emergence of the four major clades that are characterized by the presence of a TDY or TEY-A/TEY-B/TEY-C type kinase activation loop. We present evidence that after the split of TDY- and TEY-type MAPKs, initially the TEY-C clade emerged. This was followed by the TEY-B clade in early land plants until the TEY-A clade finally emerged in flowering plants. In addition to these well characterized clades, we identified another highly conserved clade of 45 MAPK-likes, members of which were previously described as Mak-homologous kinases. In agreement with their essential functions, molecular population genetic analysis of MAPK genes in Arabidopsis thaliana accessions reveal that purifying selection drove the evolution of the MAPK family, implying strong functional constraints on MAPK genes. Closely related MAPKs most likely subfunctionalized, a process in which differential transcriptional regulation of duplicates may be involved.
Publikation

Fellenberg, C.; Milkowski, C.; Hause, B.; Lange, P.-R.; Böttcher, C.; Schmidt, J.; Vogt, T.; Tapetum-specific location of a cation-dependent O-methyltransferase in Arabidopsis thaliana Plant J. 56, 132-145, (2008) DOI: 10.1111/j.1365-313X.2008.03576.x

Cation‐ and S ‐adenosyl‐l ‐methionine (AdoMet)‐dependent plant natural product methyltransferases are referred to as CCoAOMTs because of their preferred substrate, caffeoyl coenzyme A (CCoA). The enzymes are encoded by a small family of genes, some of which with a proven role in lignin monomer biosynthesis. In Arabidopsis thaliana individual members of this gene family are temporally and spatially regulated. The gene At1g67990 is specifically expressed in flower buds, and is not detected in any other organ, such as roots, leaves or stems. Several lines of evidence indicate that the At1g67990 transcript is located in the flower buds, whereas the corresponding CCoAOMT‐like protein, termed AtTSM1, is located exclusively in the tapetum of developing stamen. Flowers of At1g67990 RNAi‐suppressed plants are characterized by a distinct flower chemotype with severely reduced levels of the N  ′,N  ′′‐ bis‐(5‐hydroxyferuloyl)‐N  ′′′‐sinapoylspermidine compensated for by N1 ,N5 ,N10 ‐tris‐(5‐hydroxyferuloyl)spermidine derivative, which is characterized by the lack of a single methyl group in the sinapoyl moiety. This severe change is consistent with the observed product profile of AtTSM1 for aromatic phenylpropanoids. Heterologous expression of the recombinant protein shows the highest activity towards a series of caffeic acid esters, but 5‐hydroxyferuloyl spermidine conjugates are also accepted substrates. The in vitro substrate specificity and the in vivo RNAi‐mediated suppression data of the corresponding gene suggest a role of this cation‐dependent CCoAOMT‐like protein in the stamen/pollen development of A. thaliana .
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