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Publikationen - Molekulare Signalverarbeitung

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Bücher und Buchkapitel

Balkenhohl, T.; Kühn, H.; Wasternack, C.; Feussner, I. A lipase specific for esterified oxygenated polyenoic fatty acids in lipid bodies of cucumber cotyledons (Sánchez, J., Cerdá-Olmedo, E., Martínez-Force, E.). Secretariado de Publicaciones de la Universidad de Sevilla 320-322, (1998)

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Bücher und Buchkapitel

Feussner, I.; Balkenhohl, T.; Porzel, A.; Kühn, H.; Wasternack, C. Structural elucidation of oxygenated triacylglycerols in cucumber and sunflower cotyledons (Schreier, P., Herderich, M., Humpf, H.-U., Schwab, W.). P. Vieweg, Wiesbaden 57-58, (1998)

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Bücher und Buchkapitel

Feussner, I.; Kühn, H.; Wasternack, C. Do Lipoxygenases initiate ß-oxidation? (Williams, J.P., Mobashsher, U., Khan, M.U. & Lem, N.W.). Kluwer Academic Publishers, Dordrecht 250-252, (1997)

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Publikation

Feussner, I.; Balkenhohl, T.J.; Porzel, A.; Kühn, H.; Wasternack, C. Structural elucidation of oxygenated storage lipids in cucumber cotyledons. Implication of lipid body lipoxygenase in lipid mobilization during germination J. Biol. Chem. 272, 21635-21641, (1997)

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Publikation

Feussner, I.; Porzel, A.; Wasternack, C.; Kühn, H. Quantitative Analyse von Lipoxygenase-Metaboliten in Lipiden durch NMR-Spektroskopie Biospektrum 3, 54-58, (1997)

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Publikation

Bürstenbinder, K.; Möller, B.; Plötner; R.; Stamm, G.; Hause, G.; Mitra, D.; Abel, S. The IQD family of calmodulin-binding proteins links calcium signaling to microtubules, membrane subdomains, and the nucleus. Plant Physiol 173, 1692-1708, (2017) DOI: 10.1104/pp.16.01743

Calcium (Ca2+) signaling and dynamic reorganization of the cytoskeleton are essential processes for the coordination and control of plant cell shape and cell growth. Calmodulin (CaM) and closely related CaM-like polypeptides (CML) are principal sensors of Ca2+ signals. CaM/CMLs decode and relay information encrypted by the second messenger via differential interactions with a wide spectrum of targets to modulate their diverse biochemical activities. The plant-specific IQ67-DOMAIN (IQD) family emerged as the possibly largest class of CaM interacting proteins with undefined molecular functions and biological roles. Here, we show that the 33 members of the IQD family in Arabidopsis thaliana differentially localize, using GFP-tagged proteins, to multiple and distinct subcellular sites, including microtubule (MT) arrays, plasma membrane microdomains, and nuclear compartments. Intriguingly, the various IQD-specific localization patterns coincide with the subcellular patterns of IQD-dependent recruitment of CaM, suggesting that the diverse IQD members sequester Ca2+-CaM signaling modules to specific subcellular sites for precise regulation of Ca2+-dependent processes. Because MT localization is a hallmark of most IQD family members, we quantitatively analyzed GFP-labeled MT arrays in tobacco cells transiently expressing GFP-IQD fusions and observed IQD-specific MT patterns, which point to a role of IQDs in MT organization and dynamics. Indeed, stable overexpression of select IQD proteins in Arabidopsis altered cellular MT orientation, cell shape, and organ morphology. Because IQDs share biochemical properties with scaffold proteins, we propose that IQD families provide an assortment of platform proteins for integrating CaM-dependent Ca2+ signaling at multiple cellular sites to regulate cell function, shape, and growth. 
Publikation

Mitra, D.; Klemm, S.; Kumari, P.; Quegwer, J.; Möller, B.; Poeschl, Y.; Pflug, P.; Stamm, G.; Abel, S.; Bürstenbinder, K. Microtubule-associated protein IQ67 DOMAIN5 regulates morphogenesis of leaf pavement cells in Arabidopsis thaliana J Exp Bot 70, 529-543, (2019) DOI: 10.1093/jxb/ery395

Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation and cell morphology. Its organization and dynamics are coordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization and biological functions. We show that IQD5 is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis of iqd5 loss-of-function lines reveals functions of IQD5 in pavement cell (PC) shape morphogenesis. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced anisotropic expansion. Lastly, we demonstrate IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays and provide first evidence for important roles of calcium in regulation of PC morphogenesis. Our work thus identifies IQD5 as a novel player in PC shape regulation, and, for the first time, links calcium signaling to developmental processes that regulate anisotropic growth in PCs.
Publikation

Gerhard, B.; Fischer, K.; Balkenhohl, T.J.; Pohnert, G.; Kühn, H.; Wasternack, C.; Feussner, I. Lipoxygenase-mediated metabolism of storage lipids in germinating sunflower cotyledons and b-oxidation of (9Z,11E,13S)-13-hydroxy-octadeca-9,11-dienoic acid by the cotyledonary glyoxysomes Planta 220, 919-930, (2005)

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Publikation

Feussner, I.; Kühn, H.; Wasternack, C. Hypothesis. Do specific linoleate 13-lipoxygenases initiate b-oxidation? FEBS Letters 406, 1-5, (1997)

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Publikation

Bürstenbinder, K.; Savchenko, T.; Müller, J.; Adamson, A.W.; Stamm, G.; Kwong, R.; Zipp, B.J.; Dhurvas Chandrasekaran, D. & Abel, S. Arabidopsis calmodulin-binding protein IQ67-domain 1 localizes to microtubules and interacts with kinesin light chain-related protein-1 J Biol Chem 288, 1871-1882, (2013) DOI: 10.1074/jbc.M112.396200

Calcium (Ca2+) is a key second messenger in eukaryotes and regulates diverse cellular processes, most notably via calmodulin (CaM). In Arabidopsis thaliana, IQD1 (IQ67 domain 1) is the founding member of the IQD family of putative CaM targets. The 33 predicted IQD proteins share a conserved domain of 67 amino acids that is characterized by a unique arrangement of multiple CaM recruitment motifs, including so-called IQ motifs. Whereas IQD1 has been implicated in the regulation of defense metabolism, the biochemical functions of IQD proteins remain to be elucidated. In this study we show that IQD1 binds to multiple Arabidopsis CaM and CaM-like (CML) proteins in vitro and in yeast two-hybrid interaction assays. CaM overlay assays revealed moderate affinity of IQD1 to CaM2 (Kd ∼ 0.6 μm). Deletion mapping of IQD1 demonstrated the importance of the IQ67 domain for CaM2 binding in vitro, which is corroborated by interaction of the shortest IQD member, IQD20, with Arabidopsis CaM/CMLs in yeast. A genetic screen of a cDNA library identified Arabidopsis kinesin light chain-related protein-1 (KLCR1) as an IQD1 interactor. The subcellular localization of GFP-tagged IQD1 proteins to microtubules and the cell nucleus in transiently and stably transformed plant tissues (tobacco leaves and Arabidopsis seedlings) suggests direct interaction of IQD1 and KLCR1 in planta that is supported by GFP∼IQD1-dependent recruitment of RFP∼KLCR1 and RFP∼CaM2 to microtubules. Collectively, the prospect arises that IQD1 and related proteins provide Ca2+/CaM-regulated scaffolds for facilitating cellular transport of specific cargo along microtubular tracks via kinesin motor proteins.
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