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  1. Article ; Online: The Ime2 protein kinase family in fungi: more duties than just meiosis.

    Irniger, Stefan

    Molecular microbiology

    2011  Volume 80, Issue 1, Page(s) 1–13

    Abstract: Ime2 of the budding yeast Saccharomyces cerevisiae belongs to a family of conserved protein kinases displaying sequence similarities to both cyclin-dependent kinases and mitogen-activated protein kinases. Ime2 has a pivotal role for meiosis and ... ...

    Abstract Ime2 of the budding yeast Saccharomyces cerevisiae belongs to a family of conserved protein kinases displaying sequence similarities to both cyclin-dependent kinases and mitogen-activated protein kinases. Ime2 has a pivotal role for meiosis and sporulation. The involvement of this protein kinase in the regulation of various key events in meiosis, such as the initiation of DNA replication, the expression of meiosis-specific genes and the passage through the two consecutive rounds of nuclear divisions has been characterized in detail. More than 20 years after the identification of the IME2 gene, a recent report has provided the first evidence for a function of this gene outside of meiosis, which is the regulation of pseudohyphal growth. In the last few years, Ime2-related protein kinases from various fungal species were studied. Remarkably, these homologues are not generally required for meiosis, but instead have other specific tasks. In filamentous ascomycete species, Ime2 homologues are involved in the inhibition of fruiting body formation in response to environmental signals. In the pathogenic basidiomycetes Ustilago maydis and Cryptococcus neoformans, members of this kinase family apparently have primary roles in regulating mating. Thus, Ime2-related kinases exhibit an amazing variety in controlling sexual developmental programs in fungi.
    MeSH term(s) Intracellular Signaling Peptides and Proteins/genetics ; Intracellular Signaling Peptides and Proteins/metabolism ; Meiosis/genetics ; Meiosis/physiology ; Protein-Serine-Threonine Kinases/genetics ; Protein-Serine-Threonine Kinases/metabolism ; Saccharomyces cerevisiae/cytology ; Saccharomyces cerevisiae/enzymology ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae Proteins/genetics ; Saccharomyces cerevisiae Proteins/metabolism ; Spores, Fungal/enzymology ; Spores, Fungal/genetics ; Spores, Fungal/metabolism
    Chemical Substances Intracellular Signaling Peptides and Proteins ; Saccharomyces cerevisiae Proteins ; IME2 protein, S cerevisiae (EC 2.7.11.1) ; Protein-Serine-Threonine Kinases (EC 2.7.11.1)
    Language English
    Publishing date 2011-04
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 619315-8
    ISSN 1365-2958 ; 0950-382X
    ISSN (online) 1365-2958
    ISSN 0950-382X
    DOI 10.1111/j.1365-2958.2011.07575.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Preventing fatal destruction: inhibitors of the anaphase-promoting complex in meiosis.

    Irniger, Stefan

    Cell cycle (Georgetown, Tex.)

    2006  Volume 5, Issue 4, Page(s) 405–415

    Abstract: The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit ubiquitin-ligase whose major functions in the cell cycle are the initiation of sister chromatid separation and the inactivation of cyclin-dependent kinases. This complex is also ... ...

    Abstract The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit ubiquitin-ligase whose major functions in the cell cycle are the initiation of sister chromatid separation and the inactivation of cyclin-dependent kinases. This complex is also essential for meiosis, a specialized form of the cell cycle characterized by two consecutive rounds of chromosome segregation. To ensure a proper meiotic cell cycle, the activity of APC/C needs to be tightly controlled. It is now evident that inhibitors of APC/C play pivotal roles to avert its untimely activation. During prophase I, this ubiquitin-ligase must be kept inactive to prevent precocious sister chromatid separation. Studies in yeast showed that this inhibition is mediated by a specific subunit of the complex. Accurate chromosome segregation in meiosis I depends on spindle checkpoint proteins such as Mad2 which delay APC/C activation in response to an erroneous spindle attachment of chromosomes. Additional APC/C antagonists are known to block complete cyclin destruction between meiosis I and II, thereby ensuring that cyclin dependent kinases remain active and that DNA replication does not occur. Inhibitors of APC/C also mediate the cytostatic factor induced metaphase II arrest of oocytes. This review highlights the current knowledge about the role and relevance of these diverse regulators of the meiotic APC/C.
    MeSH term(s) Anaphase-Promoting Complex-Cyclosome ; Animals ; Chromosome Segregation/genetics ; Meiosis ; Metaphase/physiology ; Prophase/physiology ; S Phase/genetics ; Ubiquitin-Protein Ligase Complexes/antagonists & inhibitors ; Ubiquitin-Protein Ligase Complexes/metabolism
    Chemical Substances Ubiquitin-Protein Ligase Complexes (EC 2.3.2.23) ; Anaphase-Promoting Complex-Cyclosome (EC 2.3.2.27)
    Language English
    Publishing date 2006-02-15
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 2146183-1
    ISSN 1551-4005 ; 1538-4101 ; 1554-8627
    ISSN (online) 1551-4005
    ISSN 1538-4101 ; 1554-8627
    DOI 10.4161/cc.5.4.2476
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Cyclin destruction in mitosis: a crucial task of Cdc20.

    Irniger, Stefan

    FEBS letters

    2002  Volume 532, Issue 1-2, Page(s) 7–11

    Abstract: Proteolytic destruction of cyclins is a fundamental process for cell division. At the end of mitosis, degradation of mitotic cyclins results in the inactivation of cyclin-dependent kinases. Cyclin proteolysis is triggered by the anaphase-promoting ... ...

    Abstract Proteolytic destruction of cyclins is a fundamental process for cell division. At the end of mitosis, degradation of mitotic cyclins results in the inactivation of cyclin-dependent kinases. Cyclin proteolysis is triggered by the anaphase-promoting complex/cyclosome (APC/C), a multi-subunit complex which contains ubiquitin ligase activity. Recent data in yeast demonstrated that a partial degradation of the mitotic cyclin Clb2, mediated by APC/C and its activator protein Cdc20, is essential and sufficient for the mitotic exit. Remarkably, a complete inactivation of cyclin-dependent kinases seems to be not essential. This review discusses recent novel insights into cyclin destruction and its implications for the mitotic exit.
    MeSH term(s) Animals ; CDC2 Protein Kinase/metabolism ; Cdc20 Proteins ; Cdh1 Proteins ; Cell Cycle Proteins/physiology ; Cyclin B/metabolism ; Cyclins/metabolism ; Drosophila/metabolism ; Drosophila Proteins ; Fungal Proteins/metabolism ; Fungal Proteins/physiology ; Mitosis ; Models, Biological ; Protein Tyrosine Phosphatases ; Saccharomyces cerevisiae Proteins/physiology
    Chemical Substances CDC14 protein, S cerevisiae ; CDC20 protein, S cerevisiae ; CLB2 protein, S cerevisiae ; Cdc20 Proteins ; Cdh1 Proteins ; Cell Cycle Proteins ; CycB protein, Drosophila ; Cyclin B ; Cyclins ; Drosophila Proteins ; Fungal Proteins ; Saccharomyces cerevisiae Proteins ; CDC2 Protein Kinase (EC 2.7.11.22) ; Protein Tyrosine Phosphatases (EC 3.1.3.48)
    Language English
    Publishing date 2002-07-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 212746-5
    ISSN 1873-3468 ; 0014-5793
    ISSN (online) 1873-3468
    ISSN 0014-5793
    DOI 10.1016/s0014-5793(02)03657-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Fungal development and the COP9 signalosome.

    Braus, Gerhard H / Irniger, Stefan / Bayram, Ozgür

    Current opinion in microbiology

    2010  Volume 13, Issue 6, Page(s) 672–676

    Abstract: The conserved COP9 signalosome (CSN) multiprotein complex is located at the interface between cellular signaling, protein modification, life span and the development of multicellular organisms. CSN is required for light-controlled responses in ... ...

    Abstract The conserved COP9 signalosome (CSN) multiprotein complex is located at the interface between cellular signaling, protein modification, life span and the development of multicellular organisms. CSN is required for light-controlled responses in filamentous fungi. This includes the circadian rhythm of Neurospora crassa or the repression of sexual development by light in Aspergillus nidulans. In contrast to plants and animals, CSN is not essential for fungal viability. Therefore fungi are suitable models to study CSN composition, activity and cellular functions and its role in light controlled development.
    MeSH term(s) Aspergillus nidulans/growth & development ; Aspergillus nidulans/physiology ; Circadian Clocks ; Fungal Proteins/metabolism ; Gene Expression Regulation, Fungal ; Light ; Microbial Viability ; Models, Biological ; Neurospora crassa/growth & development ; Neurospora crassa/physiology ; Nuclear Proteins/metabolism ; Protein Kinases/metabolism ; Signal Transduction
    Chemical Substances Fungal Proteins ; Nuclear Proteins ; Protein Kinases (EC 2.7.-)
    Language English
    Publishing date 2010-12
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 1418474-6
    ISSN 1879-0364 ; 1369-5274
    ISSN (online) 1879-0364
    ISSN 1369-5274
    DOI 10.1016/j.mib.2010.09.011
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Controlling transcription by destruction: the regulation of yeast Gcn4p stability.

    Irniger, Stefan / Braus, Gerhard H

    Current genetics

    2003  Volume 44, Issue 1, Page(s) 8–18

    Abstract: The Gcn4 protein, a member of the AP-1 family of transcription factors, is involved in the expression of more than 500 genes in the budding yeast Saccharomyces cerevisiae. A key role of Gcn4p is the increased expression of many amino acid biosynthesis ... ...

    Abstract The Gcn4 protein, a member of the AP-1 family of transcription factors, is involved in the expression of more than 500 genes in the budding yeast Saccharomyces cerevisiae. A key role of Gcn4p is the increased expression of many amino acid biosynthesis genes in response to amino acid starvation. The accumulation of this transcription activator is mainly induced by efficient translation of the GCN4 ORF and by stabilisation of the Gcn4 protein. Under normal growth conditions, Gcn4p is a highly unstable protein, thereby resembling many eukaryotic transcription factors, including mammalian Jun and Myc proteins. Gcn4p is degraded by ubiquitin-dependent proteolysis mediated by the Skp1/cullin/F-box (SCF) ubiquitin ligase, which recognises specifically phosphorylated substrates. Two cyclin-dependent protein kinases, Pho85p and Srb10p, have crucial functions in regulating Gcn4p phosphorylation and degradation. The past few years have revealed many novel insights into these regulatory processes. Here, we summarise current knowledge about the factors and mechanisms regulating Gcn4p stability.
    MeSH term(s) Cyclin-Dependent Kinases/metabolism ; DNA-Binding Proteins/metabolism ; Gene Expression Regulation, Fungal ; Phosphorylation ; Protein Kinases/metabolism ; SKP Cullin F-Box Protein Ligases/chemistry ; SKP Cullin F-Box Protein Ligases/metabolism ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism ; Saccharomyces cerevisiae Proteins/metabolism ; Transcription, Genetic
    Chemical Substances DNA-Binding Proteins ; Saccharomyces cerevisiae Proteins ; SKP Cullin F-Box Protein Ligases (EC 2.3.2.27) ; Protein Kinases (EC 2.7.-) ; Cyclin-Dependent Kinases (EC 2.7.11.22) ; PHO85 protein, S cerevisiae (EC 2.7.11.22)
    Language English
    Publishing date 2003-10
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 282876-5
    ISSN 1432-0983 ; 0172-8083
    ISSN (online) 1432-0983
    ISSN 0172-8083
    DOI 10.1007/s00294-003-0422-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: A process independent of the anaphase-promoting complex contributes to instability of the yeast S phase cyclin Clb5.

    Sari, Fatih / Braus, Gerhard H / Irniger, Stefan

    The Journal of biological chemistry

    2007  Volume 282, Issue 36, Page(s) 26614–26622

    Abstract: Proteolytic destruction of many cyclins is induced by a multi-subunit ubiquitin ligase termed the anaphase promoting complex/cyclosome (APC/C). In the budding yeast Saccharomyces cerevisiae, the S phase cyclin Clb5 and the mitotic cyclins Clb1-4 are ... ...

    Abstract Proteolytic destruction of many cyclins is induced by a multi-subunit ubiquitin ligase termed the anaphase promoting complex/cyclosome (APC/C). In the budding yeast Saccharomyces cerevisiae, the S phase cyclin Clb5 and the mitotic cyclins Clb1-4 are known as substrates of this complex. The relevance of APC/C in proteolysis of Clb5 is still under debate. Importantly, a deletion of the Clb5 destruction box has little influence on cell cycle progression. To understand Clb5 degradation in more detail, we applied in vivo pulse labeling to determine the half-life of Clb5 at different cell cycle stages and in the presence or absence of APC/C activity. Clb5 is significantly unstable, with a half-life of approximately 8-10 min, at cell cycle periods when APC/C is inactive and in mutants impaired in APC/C function. A Clb5 version lacking its cyclin destruction box is similarly unstable. The half-life of Clb5 is further decreased in a destruction box-dependent manner to 3-5 min in mitotic or G(1) cells with active APC/C. Clb5 instability is highly dependent on the function of the proteasome. We conclude that Clb5 proteolysis involves two different modes for targeting of Clb5 to the proteasome, an APC/C-dependent and an APC/C-independent mechanism. These different modes apparently have overlapping functions in restricting Clb5 levels in a normal cell cycle, but APC/C function is essential in the presence of abnormally high Clb5 levels.
    MeSH term(s) Anaphase-Promoting Complex-Cyclosome ; Cyclin B/genetics ; Cyclin B/metabolism ; Cyclins/genetics ; Cyclins/metabolism ; G1 Phase/physiology ; Half-Life ; Proteasome Endopeptidase Complex/genetics ; Proteasome Endopeptidase Complex/metabolism ; Protein Processing, Post-Translational/physiology ; S Phase/physiology ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism ; Saccharomyces cerevisiae Proteins/genetics ; Saccharomyces cerevisiae Proteins/metabolism ; Ubiquitin-Protein Ligase Complexes/genetics ; Ubiquitin-Protein Ligase Complexes/metabolism
    Chemical Substances CLB5 protein, S cerevisiae ; Cyclin B ; Cyclins ; Saccharomyces cerevisiae Proteins ; Ubiquitin-Protein Ligase Complexes (EC 2.3.2.23) ; Anaphase-Promoting Complex-Cyclosome (EC 2.3.2.27) ; Proteasome Endopeptidase Complex (EC 3.4.25.1)
    Language English
    Publishing date 2007-07-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    DOI 10.1074/jbc.M703744200
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: The protein kinase ImeB is required for light-mediated inhibition of sexual development and for mycotoxin production in Aspergillus nidulans.

    Bayram, Ozgür / Sari, Fatih / Braus, Gerhard H / Irniger, Stefan

    Molecular microbiology

    2009  Volume 71, Issue 5, Page(s) 1278–1295

    Abstract: Spore formation is a common process in the developmental cycle of fungi. In the yeast Saccharomyces cerevisiae, Ime2 is a key protein kinase for the meiotic cell cycle, which precedes ascospore formation. Here, we analysed the IME2-related imeB gene of ... ...

    Abstract Spore formation is a common process in the developmental cycle of fungi. In the yeast Saccharomyces cerevisiae, Ime2 is a key protein kinase for the meiotic cell cycle, which precedes ascospore formation. Here, we analysed the IME2-related imeB gene of the filamentous ascomycete Aspergillus nidulans. imeB deletion strains are retarded in growth and overproduce fertile sexual fruiting bodies in the presence of light, which normally represses sexual development. imeB mutants also display abnormal differentiation of sexual Hülle cells in submerged cultures. Increased sexual development of imeB mutants is dependent on VeA, a component of the heterotrimeric velvet complex. A combined deletion of imeB with the phytochrome fphA, a red light receptor, results in a complete loss of light response, suggesting that ImeB and FphA cooperate in light-mediated inhibition of sexual development. Furthermore, we found that imeB mutants fail to produce the mycotoxin sterigmatocystin, an aflatoxin precursor, and show that ImeB is needed for expression of the sterigmatocystin gene cluster. ImeB contains a TXY motif conserved in mitogen-activated protein kinases. This sequence element is essential for ImeB function. We conclude that ImeB is a mitogen-activated protein kinase-related protein kinase required for the co-ordinated control of light-dependent development with mycotoxin production.
    MeSH term(s) Amino Acid Sequence ; Aspergillus nidulans/genetics ; Aspergillus nidulans/growth & development ; Aspergillus nidulans/metabolism ; Fungal Proteins/genetics ; Fungal Proteins/metabolism ; Gene Deletion ; Gene Expression Regulation, Developmental ; Gene Expression Regulation, Fungal ; Genetic Complementation Test ; Light ; Molecular Sequence Data ; Multigene Family ; Mycotoxins/biosynthesis ; Protein Kinases/genetics ; Protein Kinases/metabolism ; RNA, Fungal/metabolism ; Sequence Alignment ; Spores, Fungal/genetics ; Spores, Fungal/growth & development ; Spores, Fungal/metabolism
    Chemical Substances Fungal Proteins ; Mycotoxins ; RNA, Fungal ; Protein Kinases (EC 2.7.-)
    Language English
    Publishing date 2009-03
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 619315-8
    ISSN 1365-2958 ; 0950-382X
    ISSN (online) 1365-2958
    ISSN 0950-382X
    DOI 10.1111/j.1365-2958.2009.06606.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Book ; Online ; Thesis: Formation of messenger RNA 3' ends in the yeast Saccharomyces cerevisiae

    Irniger, Stefan

    1992  

    Author's details by Stefan Irniger
    Language English
    Size Online-Ressource (144 S), Ill
    Publishing place Zürich
    Document type Book ; Online ; Thesis
    Thesis / German Habilitation thesis Diss. Naturwiss. ETH Zürich, Nr. 9820. Ref.: R. Hütter ; Korref.: G. Braus ; Korref.: H. Hennecke--Zürich, 9820
    Database Former special subject collection: coastal and deep sea fishing

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  9. Book ; Online ; Thesis: The role of Pcl5p and Pcl7p in the Gcn4p stability regulation of Saccharomyces cerevisiae

    Schulze, Florian [Verfasser] / Braus, Gerhard [Akademischer Betreuer] / Irniger, Stefan [Akademischer Betreuer]

    2011  

    Author's details Florian Schulze. Gutachter: Gerhard Braus ; Stefan Irniger. Betreuer: Gerhard Braus
    Keywords Biowissenschaften, Biologie ; Life Science, Biology
    Subject code sg570
    Language English
    Publisher Niedersächsische Staats- und Universitätsbibliothek Göttingen
    Publishing place Göttingen
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

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  10. Book ; Online ; Thesis: Impact of plant species, N fertilization and ecosystem engineers on the structure and function of soil microbial communities

    Pfeiffer, Birgit / Daniel, Rolf / Heimel, Kai / Hoppert, Michael / Irniger, Stefan / Jungkunst, Hermann / Pöggeler, Stefanie

    2014  

    Abstract: Mikrobielle Gemeinschaften werden direkt und indirekt von einem komplexen System verschiedenster Interaktionen zwischen biotischen und abiotischen Faktoren beeinflusst. So zum Beispiel von verschiedenen Pflanzenarten und ihren jeweiligen Eigenschaften, ... ...

    Author's details vorgelegt von Birgit Pfeiffer
    Abstract Mikrobielle Gemeinschaften werden direkt und indirekt von einem komplexen System verschiedenster Interaktionen zwischen biotischen und abiotischen Faktoren beeinflusst. So zum Beispiel von verschiedenen Pflanzenarten und ihren jeweiligen Eigenschaften, dem Nährstoffgehalt des Bodens, sowie dem pH-Wert. Im Gegenzug gestalten Mikroorganismen als wichtige Treiber der C- und N-Kreisläufe ihre Umwelt. Im Rahmen der vorliegenden Arbeit wurden mehrere Studien unter kontrollierten Feld- und Laborbedingungen, sowie unter natürlichen Bedingungen im Freiland durchgeführt, um verschiedene Einflussfakto...

    Soil microbial communities are directly and indirectly influenced by a complex system of cross-interactions between different biotic and abiotic factors influencing each other, such as plant species and their respective traits, soil nutrient content, and pH. Microorganisms shape their environment, as important drivers of the C and N cycle. Within the present thesis, several studies were conducted under controlled field and laboratory conditions as well as under natural conditions to unravel the contribution of different influencing factors. The soil prokaryotic community composition of the ...
    Language English
    Size Online-Ressource (PDF-Datei: 12, MB)
    Document type Book ; Online ; Thesis
    Thesis / German Habilitation thesis --Göttingen, Univ., Diss., 2014
    Database Former special subject collection: coastal and deep sea fishing

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