Small-GTPase-Associated Signaling by the Guanine Nucleotide Exchange Factors CpDock180 and CpCdc24, the GTPase Effector CpSte20, and the Scaffold Protein CpBem1 in Claviceps purpurea

Herrmann, Andrea; Tillmann, Britta A. M.; Schürmann, Janine; Bölker, Michael; Tudzynski, Paul

doi:10.1128/ec.00332-13

Cited by 17 publications

(17 citation statements)

References 89 publications

(133 reference statements)

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“…Those processes were shown to be regulated by the Nox‐complex in fungi (Brun et al ., ; Takemoto et al ., ; Kayano et al ., ; Ryder et al ., ). Moreover, Δ bciqg1 match the phenotype of mutants of other Nox complex components like BcRac, BcCdc42 and BcBem1 partially in B. cinerea as well as in other fungi (Takemoto et al ., ; Herrmann et al ., ).…”

Section: Discussionmentioning

confidence: 97%

BcIqg1, a fungal IQGAP homolog, interacts with NADPH oxidase, MAP kinase and calcium signaling proteins and regulates virulence and development in Botrytis cinerea

Marschall

Tudzynski

2016

Molecular Microbiology

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NADPH oxidases (Nox) produce reactive oxygen species (ROS) in multicellular eukaryotic organisms. They trigger defense reactions ('oxidative burst') - in phagocytes and plant cells -, and are involved in a broad range of differentiation processes. Fungal Nox-complexes play a central role in vegetative, sexual and pathogenic processes. In contrast to mammalian systems, knowledge is limited about composition, localisation and connection to major signaling cascades in fungi. Here, we characterize a fungal homolog of the RasGAP scaffold protein IQGAP, which links several major signaling processes, including Nox in mammalian cell lines. We show that BcIqg1 interacts directly with a cytosolic, regulatory component (BcRac) and a membrane-associated subunit (BcNoxD) of a Nox-complex in the pathogen Botrytis cinerea. Thus, this protein may be a scaffold that mediates interaction of the catalytic subunits with the regulator BcNoxR. The protein interacts with modules of the MAP kinase- and calcium-dependent signaling pathways. Functional analysis of BcIqg1 substantiated its involvement in different signaling pathways. It mediates the Ca(2+) -triggered nuclear translocation of - BcCRZ1 and the MAP kinase BcBmp1. BcIqg1 is involved in resistance against oxidative and membrane stress and is required for several developmental processes including formation of sclerotia, conidial anastomosis tubes and infection cushions as well as for virulence.

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Section: Discussionmentioning

confidence: 97%

BcIqg1, a fungal IQGAP homolog, interacts with NADPH oxidase, MAP kinase and calcium signaling proteins and regulates virulence and development in Botrytis cinerea

Marschall

Tudzynski

2016

Molecular Microbiology

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“…during CAT formation, for BcNoxB during appressorial penetration). Additional subunits, like Bem1, which possesses similar protein domains as the mammalian p40phox, or the GEF (guanine nucleotide exchange factor) Cdc24 have been identified in fungi and were shown to interact with NoxR in E. festucae and C. purpurea (Takemoto et al ., ; Schürmann et al ., ; Herrmann et al ., ).…”

Section: Discussionmentioning

confidence: 97%

“…It was shown that the scaffold protein Bem1, whose domain structure is similar to that of p40phox, interacts with NoxR in Epichloë festucae and C. purpurea via their PB1 domains (Takemoto et al ., ; Schürmann et al ., ). Furthermore, the guanine nucleotide exchange factor Cdc24 also interacts with NoxR in E. festucae and C. purpurea (Takemoto et al ., ; Herrmann et al ., ). Recently, the tetraspanin Pls1, also a transmembrane protein, was suggested to be associated with NoxB.…”

Section: Introductionmentioning

confidence: 97%

BcNoxD, a putative ER protein, is a new component of the NADPH oxidase complex in Botrytis cinerea

Siegmund

Marschall

Tudzynski

2014

Molecular Microbiology

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SummaryNADPH oxidases (Nox) are major enzymatic producer of reactive oxygen species (ROS). In fungi these multi-enzyme complexes are involved in sexual differentiation and pathogenicity. However, in contrast to mammalian systems, the composition and recruitment of the fungal Nox complexes are unresolved. Here we introduce a new Nox component, the membrane protein NoxD in the grey mold fungus Botrytis cinerea. It has high homology to the ER protein Pro41 from Sordaria macrospora, similar functions to the catalytic Nox subunit BcNoxA in differentiation and pathogenicity, and shows similarities to phagocytic p22phox. BcNoxA and BcNoxD interact with each other. Both proteins are involved in pathogenicity, fusion of conidial anastomosis tubes (CAT) and formation of sclerotia and conidia. These data support our earlier view based on localization studies, for an ER-related function of the Nox complex. We present the first evidence that some functions of the BcNoxA complex are indeed linked to the ER, while others clearly require export from the ER.

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“…E. festucae , suggest that the scaffold protein Bem1 and the GEF (guanine nucleotide exchange factor) Cdc24 are part of the Nox complex. In E. festucae and C. purpurea a direct interaction via the PB1 domains (Phox and Bem1p -mediates protein-protein interactions) was shown between NoxR, Bem1 and Cdc24 (Herrmann et al 2014 ;Schürmann et al 2013 ;Takemoto et al 2011 ). Comparable studies in B. cinerea did not show a similar interaction of Bem1 and Cdc24 with NoxR.…”

Section: Components Of B Cinerea Nox Complexes Function and Organizmentioning

confidence: 78%

Reactive Oxygen Species in the Botrytis – Host Interaction

Siegmund

Viefhues

2015

Botrytis – The Fungus, the Pathogen and Its Management in Agricultural Systems

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Reactive oxygen species (ROS) are unavoidable byproducts of several metabolic processes. Due to their high reactivity they can cause molecular damages such as protein oxidations or DNA mutations, but they also serve as important signalling molecules within cells. Intracellular ROS primarily originate in the mitochondria; however enzymatic ROS generating systems such as the membrane associated NADPH oxidase complex (Nox) contribute to their production. In particular, during host-pathogen interactions ROS are of key importance for plant defence but also for fungal attack. As an early response to pathogen infestation the plant releases high amounts of reactive oxygen species to counteract the pathogen, known as the oxidative burst. It was shown that Botrytis exploits this plant defence reaction and even contributes to this oxidative burst by forming its' own ROS. Thus, the fungus needs a robust oxidative stress responsive (OSR) system to cope with ROS. In order to balance the intracellular redox state, effective antioxidant systems, including the thioredoxin and the glutathione system, are indispensable. Furthermore, catalases, superoxide dismutases and several peroxidases support ROS scavenging by enzymatic inactivation. Transcription factors such as the Botrytis activator protein (Bap1) and the response regulator Skn7 were shown to be involved in OSR. In this chapter we discuss the role of ROS in Botrytis -host interaction and both ROS generating and detoxifying systems and their importance for Botrytis pathogenicity. Keywords ROS • NADPH oxidases • Thioredoxin • Glutathione • Oxidative stress Reactive Oxygen Species (ROS)Reactive oxygen species (ROS) are generated in all aerobic environments and play a major role for all organisms dependent on oxygen. The oxygen in our atmosphere facilitated the evolution of multi-cellular organisms, but is also the source for several

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Small-GTPase-Associated Signaling by the Guanine Nucleotide Exchange Factors CpDock180 and CpCdc24, the GTPase Effector CpSte20, and the Scaffold Protein CpBem1 in Claviceps purpurea

Cited by 17 publications

References 89 publications

BcIqg1, a fungal IQGAP homolog, interacts with NADPH oxidase, MAP kinase and calcium signaling proteins and regulates virulence and development in Botrytis cinerea

BcIqg1, a fungal IQGAP homolog, interacts with NADPH oxidase, MAP kinase and calcium signaling proteins and regulates virulence and development in Botrytis cinerea

BcNoxD, a putative ER protein, is a new component of the NADPH oxidase complex in Botrytis cinerea

Reactive Oxygen Species in the Botrytis – Host Interaction

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