The dynamics of signal complex formation mediating germling fusion in Neurospora crassa

Serrano, Antonio; Hammadeh, Hamzeh Haj; Herzog, Stephanie; Illgen, Julia; Schumann, Marcel; Weichert, Martin; Fleiβner, André

doi:10.1016/j.fgb.2017.02.003

Cited by 7 publications

(4 citation statements)

References 9 publications

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“…Vegetative spores (conidia) of this fungus undergo mutual attraction and fusion briefly after germination. Consecutive fusion events merge numerous individuals into one syncytial unit, which further develops into the mycelial fungal colony (Glass et al, 2004;Serrano et al, 2017). During the positive tropic interaction of two germinating spores (called 'germlings'), both cells rapidly alternate between two physiological stages, indicated by the oscillating recruitment of the MAK-2 MAPK module to the plasma membrane of the growing cell tips.…”

Section: Introductionmentioning

confidence: 99%

Spatio-temporal MAPK dynamics mediate cell behavior coordination during fungal somatic cell fusion

Serrano

Illgen

Brandt

et al. 2018

Journal of Cell Science

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Mitogen-activated protein kinases (MAPKs) are conserved regulators of proliferation, differentiation and adaptation in eukaryotic cells. Their activity often involves changes in their subcellular localization, indicating an important role for these spatio-temporal dynamics in signal transmission. A striking model illustrating these dynamics is somatic cell fusion in Germinating spores of this fungus rapidly alternate between signal sending and receiving, thereby establishing a cell-cell dialog, which involves the alternating membrane recruitment of the MAPK MAK-2 in both fusion partners. Here, we show that the dynamic translocation of MAK-2 is essential for coordinating the behavior of the fusion partners before physical contact. The activation and function of the kinase strongly correlate with its subcellular localization, indicating a crucial contribution of the MAPK dynamics in establishing regulatory feedback loops, which establish the oscillatory signaling mode. In addition, we provide evidence that MAK-2 not only contributes to cell-cell communication, but also mediates cell-cell fusion. The MAK-2 dynamics significantly differ between these two processes, suggesting a role for the MAPK in switching of the cellular program between communication and fusion.

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Section: Introductionmentioning

confidence: 99%

Spatio-temporal MAPK dynamics mediate cell behavior coordination during fungal somatic cell fusion

Serrano

Illgen

Brandt

et al. 2018

Journal of Cell Science

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“…In N. crassa , MAP kinases, the striatin-interacting protein phosphatase and kinase (STRIPAK) complex and the NADPH oxidase complex, together with fungal specific proteins are wired into an intricate signaling network to mediate hyphal fusion events (Herzog et al, 2015). The MAK-2 protein and the fungal specific protein SO/HAM-1 participate in cellular crosstalk known as “ping-pong signaling” where both proteins are recruited to the plasma membrane of the growing tips in an oscillatory manner, with one phase lasting between 6 and 12 min (Fleissner et al, 2009; Serrano et al, 2017). HAM-5 functions as a scaffold-like protein proposed to link the activation of the MAK-2 cascade to upstream factors and proteins involved in hyphal fusion (Jonkers et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

A Cellular Fusion Cascade Regulated by LaeA Is Required for Sclerotial Development in Aspergillus flavus

et al. 2017

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Aspergillus flavus is a saprophytic soil fungus that poses a serious threat worldwide as it contaminates many food and feed crops with the carcinogenic mycotoxin called aflatoxin. This pathogen persists as sclerotia in the soil which enables fungal survival in harsh environmental conditions. Sclerotia formation by A. flavus depends on successful cell communication and hyphal fusion events. Loss of LaeA, a conserved developmental regulator in fungi, abolishes sclerotia formation in this species whereas overexpression (OE) of laeA results in enhanced sclerotia production. Here we demonstrate that sclerotia loss and inability to form heterokaryons in A. flavusΔlaeA is mediated by homologs of the Neurospora crassa ham (hyphal anastomosis) genes termed hamE-I in A. flavus. LaeA positively regulates ham gene expression and deletion of hamF, G, H, or I phenocopies ΔlaeA as demonstrated by heterokaryon and sclerotia loss and reduced aflatoxin synthesis and virulence of these mutants. Deletion of hamE showed a less severe phenotype. hamE-I homologs are positively regulated by the clock controlled transcription factor ADV-1 in N. crassa. Similarly, the ADV-1 homolog NosA regulates hamE-I expression in A. flavus, is required for sclerotial development and is itself positively regulated by LaeA. We speculate that a putative LaeA>NosA>fusion cascade underlies the previously described circadian clock regulation of sclerotia production in A. flavus.

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“…Thus, future delineation of the biochemical events that lead to the increase in agglutination, along with the rapid germination observed in the phosphomimetic mutants and the alleles analyzed in this study, could well be assisted by transcriptional analysis of the mentioned strains during the initial phases of germination. The mentioned strain and its phenotypic attributes may well assist in the temporal and spatial analysis of events involved in the attraction, agglutination, CAT formation and cell wall remodeling and complement what has been elegantly established so far (Fu et al, , Herzog et al, ; Serrano et al, ).…”

Section: Discussionmentioning

confidence: 97%

Altering Neurospora crassa MOB2A exposes its functions in development and affects its interaction with the NDR kinase COT1

Aharoni-Kats

Zelinger

Chen

et al. 2018

Molecular Microbiology

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The Neurospora crassa Mps One Binder (MOB) proteins MOB2A and MOB2B physically interact with the Nuclear Dbf2 Related (NDR) kinase COT1 and have been shown to have overlapping functions in various aspects of asexual development. Here, we identified two N. crassa MOB2A residues, Tyr117 and Tyr119, which are potentially phosphorylated. Using phosphomimetic mob-2a mutants we have been able to establish that apart from their previously described roles, MOB2A/B are involved in additional developmental processes. Enhanced conidial germination, accompanied by conidial agglutination, in the phosphomimetic mutants indicated that MOB2A is a negative regulator of germination. Thick-section imaging of perithecia revealed slow maturation and a lack of asci alignment in the mutant strains demonstrating a role for MOB2A in sexual development. We demonstrate that even though MOB2A and MOB2B have some overlapping functions, MOB2B cannot compensate for the roles MOB2A has in conidiation and germination. Altering Tyr residues 117 and 119 impaired the physical interactions between MOB2A and COT1, most likely contributing to some of the observed effects. As cot-1 and the phosphomimetic mutants share an extragenic suppressor (gul-1), we concluded that at least some of the effects imposed by altering Tyr117 and Tyr119 are mediated by the NDR kinase.

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The dynamics of signal complex formation mediating germling fusion in Neurospora crassa

Cited by 7 publications

References 9 publications

Spatio-temporal MAPK dynamics mediate cell behavior coordination during fungal somatic cell fusion

Spatio-temporal MAPK dynamics mediate cell behavior coordination during fungal somatic cell fusion

A Cellular Fusion Cascade Regulated by LaeA Is Required for Sclerotial Development in Aspergillus flavus

Altering Neurospora crassa MOB2A exposes its functions in development and affects its interaction with the NDR kinase COT1

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