Ischebeck, Till

[["dc.bibliographiccitation.firstpage","453"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","The Plant Journal"],["dc.bibliographiccitation.lastpage","468"],["dc.bibliographiccitation.volume","65"],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Stenzel, Irene"],["dc.contributor.author","Hempel, Franziska"],["dc.contributor.author","Jin, X. U."],["dc.contributor.author","Mosblech, Alina"],["dc.contributor.author","Heilmann, Ingo"],["dc.date.accessioned","2018-11-07T08:59:38Z"],["dc.date.available","2018-11-07T08:59:38Z"],["dc.date.issued","2011"],["dc.description.abstract","P>The regulation of pollen tube growth by the phospholipid phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) is not well understood. The Arabidopsis genome encodes two type A phosphatidylinositol-4-phosphate (PI4P) 5-kinases, PIP5K10 and PIP5K11, which are exclusively expressed in pollen and produce PtdIns(4,5)P(2)in vitro. Fluorescence-tagged PIP5K10 and PIP5K11 localized to lateral subapical plasma membrane microdomains in tobacco pollen tubes in a pattern closely resembling the distribution of PtdIns(4,5)P(2,) with the exception of notably weaker association at the extreme apex. Overexpression of PIP5K10 or PIP5K11 in tobacco pollen tubes resulted in severe tip swelling and altered actin fine structure similar to that reported for overexpression of tobacco Nt-Rac5, a monomeric GTPase known to regulate the actin cytoskeleton. Increased sensitivity of Arabidopsis pip5k10 pip5k11 double mutant pollen tubes to Latrunculin B (LatB) further supports a role for type A PI4P 5-kinases in controlling the actin cytoskeleton. Despite the disruption of both its type A PI4P 5-kinases, the pip5k10 pip5k11 double mutant was fertile, indicating that one of the remaining type B PI4P 5-kinase isoforms might be functionally redundant with PIP5K10 and PIP5K11. Antagonistic effects of PIP5K11 and the Nt-Rac5-specific guanine nucleotide dissociation inhibitor, Nt-RhoGDI2, on tip swelling observed in coexpression-titration experiments indicate a link between PtdIns(4,5)P(2) and Rac-signaling in pollen tubes. The data suggest that type A PI4P 5-kinases influence the actin cytoskeleton in pollen tubes in part by counteracting Nt-RhoGDI2, possibly contributing to the control of the pool of plasma membrane-associated Nt-Rac5."],["dc.description.sponsorship","German Research Foundation (DFG) [He3424/1]"],["dc.identifier.doi","10.1111/j.1365-313X.2010.04435.x"],["dc.identifier.isi","000286619000011"],["dc.identifier.pmid","21265898"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/23950"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell Publishing, Inc"],["dc.relation.issn","0960-7412"],["dc.title","Phosphatidylinositol-4,5-bisphosphate influences Nt-Rac5-mediated cell expansion in pollen tubes of Nicotiana tabacum"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4894"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","The Plant Cell"],["dc.bibliographiccitation.lastpage","4911"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Werner, Stephanie"],["dc.contributor.author","Krishnamoorthy, Praveen"],["dc.contributor.author","Lerche, Jennifer"],["dc.contributor.author","Meijon, Monica"],["dc.contributor.author","Stenzel, Irene"],["dc.contributor.author","Loefke, Christian"],["dc.contributor.author","Wiessner, Theresa"],["dc.contributor.author","Im, Yang Ju"],["dc.contributor.author","Perera, Imara Y."],["dc.contributor.author","Iven, Tim"],["dc.contributor.author","Feussner, Ivo"],["dc.contributor.author","Busch, Wolfgang"],["dc.contributor.author","Boss, Wendy F."],["dc.contributor.author","Teichmann, Thomas"],["dc.contributor.author","Hause, Bettina"],["dc.contributor.author","Persson, Staffan"],["dc.contributor.author","Heilmann, Ingo"],["dc.date.accessioned","2018-11-07T09:16:43Z"],["dc.date.available","2018-11-07T09:16:43Z"],["dc.date.issued","2013"],["dc.description.abstract","The functions of the minor phospholipid phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P-2] during vegetative plant growth remain obscure. Here, we targeted two related phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) PIP5K1 and PIP5K2, which are expressed ubiquitously in Arabidopsis thaliana. A pip5k1 pip5k2 double mutant with reduced PtdIns(4,5)P-2 levels showed dwarf stature and phenotypes suggesting defects in auxin distribution. The roots of the pip5k1 pip5k2 double mutant had normal auxin levels but reduced auxin transport and altered distribution. Fluorescence-tagged auxin efflux carriers PIN-FORMED (PIN1)-green fluorescent protein (GFP) and PIN2-GFP displayed abnormal, partially apolar distribution. Furthermore, fewer brefeldin A-induced endosomal bodies decorated by PIN1-GFP or PIN2-GFP formed in pip5k1 pip5k2 mutants. Inducible overexpressor lines for PIP5K1 or PIP5K2 also exhibited phenotypes indicating misregulation of auxin-dependent processes, and immunolocalization showed reduced membrane association of PIN1 and PIN2. PIN cycling and polarization require clathrin-mediated endocytosis and labeled clathrin light chain also displayed altered localization patterns in the pip5k1 pip5k2 double mutant, consistent with a role for PtdIns(4,5)P-2 in the regulation of clathrin-mediated endocytosis. Further biochemical tests on subcellular fractions enriched for clathrin-coated vesicles (CCVs) indicated that pip5k1 and pip5k2 mutants have reduced CCV-associated PI4P 5-kinase activity. Together, the data indicate an important role for PtdIns(4,5)P-2 in the control of clathrin dynamics and in auxin distribution in Arabidopsis."],["dc.identifier.doi","10.1105/tpc.113.116582"],["dc.identifier.isi","000330611200014"],["dc.identifier.pmid","24326589"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27998"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Plant Biologists"],["dc.relation.issn","1532-298X"],["dc.relation.issn","1040-4651"],["dc.title","Phosphatidylinositol 4,5-Bisphosphate Influences PIN Polarization by Controlling Clathrin-Mediated Membrane Trafficking in Arabidopsis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3312"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","The Plant Cell"],["dc.bibliographiccitation.lastpage","3330"],["dc.bibliographiccitation.volume","20"],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Stenzel, Irene"],["dc.contributor.author","Heilmann, Ingo"],["dc.date.accessioned","2018-11-07T11:08:50Z"],["dc.date.available","2018-11-07T11:08:50Z"],["dc.date.issued","2008"],["dc.description.abstract","Phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P(2)] occurs in the apical plasma membrane of growing pollen tubes. Because enzymes responsible for PtdIns(4,5) P(2) production at that location are uncharacterized, functions of PtdIns( 4,5) P(2) in pollen tube tip growth are unresolved. Two candidate genes encoding pollen-expressed Arabidopsis thaliana phosphatidylinositol-4-phosphate 5-kinases (PI4P 5-kinases) of Arabidopsis subfamily B were identified (PIP5K4 and PIP5K5), and their recombinant proteins were characterized as being PI4P 5-kinases. Pollen of T-DNA insertion lines deficient in both PIP5K4 and PIP5K5 exhibited reduced pollen germination and defects in pollen tube elongation. Fluorescence-tagged PIP5K4 and PIP5K5 localized to an apical plasma membrane microdomain in Arabidopsis and tobacco (Nicotiana tabacum) pollen tubes, and overexpression of either PIP5K4 or PIP5K5 triggered multiple tip branching events. Further studies using the tobacco system revealed that overexpression caused massive apical pectin deposition accompanied by plasma membrane invaginations. By contrast, callose deposition and cytoskeletal structures were unaltered in the overexpressors. Morphological effects depended on PtdIns(4,5) P(2) production, as an inactive enzyme variant did not produce any effects. The data indicate that excessive PtdIns(4,5) P2 production by type B PI4P 5-kinases disturbs the balance of membrane trafficking and apical pectin deposition. Polar tip growth of pollen tubes may thus be modulated by PtdIns(4,5) P(2) via regulatory effects on membrane trafficking and/or apical pectin deposition."],["dc.description.sponsorship","German Research Foundation"],["dc.identifier.doi","10.1105/tpc.108.059568"],["dc.identifier.isi","000262861700015"],["dc.identifier.pmid","19060112"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52881"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Plant Biologists"],["dc.relation.issn","1040-4651"],["dc.title","Type B Phosphatidylinositol-4-Phosphate 5-Kinases Mediate Arabidopsis and Nicotiana tabacum Pollen Tube Growth by Regulating Apical Pectin Secretion"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","124"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","The Plant Cell"],["dc.bibliographiccitation.lastpage","141"],["dc.bibliographiccitation.volume","20"],["dc.contributor.author","Stenzel, Irene"],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Koenig, Sabine"],["dc.contributor.author","Holubowska, Anna"],["dc.contributor.author","Sporysz, Marta"],["dc.contributor.author","Hause, Bettina"],["dc.contributor.author","Heilmann, Ingo"],["dc.date.accessioned","2018-11-07T11:20:40Z"],["dc.date.available","2018-11-07T11:20:40Z"],["dc.date.issued","2008"],["dc.description.abstract","Root hairs are extensions of root epidermal cells and a model system for directional tip growth of plant cells. A previously uncharacterized Arabidopsis thaliana phosphatidylinositol-4-phosphate 5-kinase gene (PIP5K3) was identified and found to be expressed in the root cortex, epidermal cells, and root hairs. Recombinant PIP5K3 protein was catalytically active and converted phosphatidylinositol-4-phosphate to phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P(2)]. Arabidopsis mutant plants homozygous for T-DNA-disrupted PIP5K3 alleles were compromised in root hair formation, a phenotype complemented by expression of wild-type PIP5K3 cDNA under the control of a 1500-bp PIP5K3 promoter fragment. Root hair-specific PIP5K3 overexpression resulted in root hair deformation and loss of cell polarity with increasing accumulation of PIP5K3 transcript. Using reestablishment of root hair formation in T-DNA mutants as a bioassay for physiological functionality of engineered PIP5K3 variants, catalytic activity was found to be essential for physiological function, indicating that PtdIns(4,5)P(2) formation is required for root hair development. An N-terminal domain containing membrane occupation and recognition nexus repeats, which is not required for catalytic activity, was found to be essential for the establishment of root hair growth. Fluorescence-tagged PIP5K3 localized to the periphery of the apical region of root hair cells, possibly associating with the plasma membrane and/or exocytotic vesicles. Transient heterologous expression of full-length PIP5K3 in tobacco (Nicotiana tabacum) pollen tubes increased plasma membrane association of a PtdIns(4,5)P(2)-specific reporter in these tip-growing cells. The data demonstrate that root hair development requires PIP5K3-dependent PtdIns(4,5)P(2) production in the apical region of root hair cells."],["dc.identifier.doi","10.1105/tpc.107.052852"],["dc.identifier.isi","000256414400011"],["dc.identifier.pmid","18178770"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55594"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Plant Biologists"],["dc.relation.issn","1040-4651"],["dc.title","The type B phosphatidylinositol-4-phosphate 5-kinase 3 is essential for root hair formation in Arabidopsis thaliana"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","870"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Molecular Plant"],["dc.bibliographiccitation.lastpage","881"],["dc.bibliographiccitation.volume","3"],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Vu, Linh Hai"],["dc.contributor.author","Jin, X. U."],["dc.contributor.author","Stenzel, Irene"],["dc.contributor.author","Loefke, Christian"],["dc.contributor.author","Heilmann, Ingo"],["dc.date.accessioned","2018-11-07T08:39:59Z"],["dc.date.available","2018-11-07T08:39:59Z"],["dc.date.issued","2010"],["dc.description.abstract","The Arabidopsis phosphoinositide kinases PI4K beta 1 and PIP5K5 have been implicated in the control of directional vesicle trafficking underlying polar tip growth in pollen tubes. PI4K beta 1 and PIP5K5 catalyze key consecutive steps of phosphoinositide conversion, and it appears obvious that phosphatidylinositol-4-phosphate formed by PI4K beta 1 might act as a substrate for phosphatidylinositol-4,5-bisphosphate formation by PIP5K5. However, this hypothesis has not been experimentally addressed and distinct localization patterns of PI4K beta 1, PIP5K5, and also PI-synthases (PIS) generating phosphatidylinositol suggest additional complexity. Here, the synergistic functionality of enzymes of phosphoinositide conversion was assessed. In tobacco and Arabidopsis pollen tubes, phosphoinositides influence the apical secretion of pectin, and increased pectin deposition results in characteristic morphological alterations. Catalytically active and dominant negative variants of PI4K beta 1 and PIP5K5 were systematically co-expressed in tobacco pollen tubes and the incidence of morphologies related to enhanced pectin secretion was evaluated. The data support a proposed functional interplay of PI4K beta 1 and PIP5K5 at the trans-Golgi network, mediating directional vesicle trafficking. Co-expression experiments additionally including PIS isoforms, PIS1 or PIS2, indicate that pectin secretion is synergistically mediated by PI4K beta 1 and PIP5K5 acting on PtdIns formed by PIS2 rather than PIS1. Possible ramifications for the preferential channeling of phosphoinositide intermediates between particular isoforms of PI pathway enzymes are discussed."],["dc.description.sponsorship","German Research Foundation [He3424/1]"],["dc.identifier.doi","10.1093/mp/ssq031"],["dc.identifier.isi","000282173900008"],["dc.identifier.pmid","20603382"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19127"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press"],["dc.relation.issn","1752-9867"],["dc.relation.issn","1674-2052"],["dc.title","Functional Cooperativity of Enzymes of Phosphoinositide Conversion According to Synergistic Effects on Pectin Secretion in Tobacco Pollen Tubes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]