From Function to Shape: A Novel Role of a Formin in Morphogenesis of the Fungus<i>Ashbya gossypii</i>

Schmitz, Hans‐Peter; Kaufmann, Andreas M.; Köhli, Michael; Laissue, Pierre Philippe; Philippsen, Peter

doi:10.1091/mbc.e05-06-0479

Cited by 64 publications

(86 citation statements)

References 77 publications

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“…Formins assist nucleating microfilament formation at polarization sites (Evangelista et al 2003;Pearson et al 2004;Schmitz et al 2006), but the formation of a stable axis of hyphal polarity can occur in their absence, as shown for A. nidulans (Sharpless and Harris 2002). On the other hand, regulators of actin patch formation and dynamics appear to be essential for the formation of a stable axis Upadhyay and Shaw 2008;Hervas-Aguilar and Penalva 2010).…”

Section: The Cytoskeletonmentioning

confidence: 97%

Fungal Morphogenesis

Lin

Alspaugh

Liu

et al. 2014

Cold Spring Harbor Perspectives in Medicine

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Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and how morphogenesis, in turn, shapes the fungal microenvironment. PROPERTIES OF MORPHOGENESIS IN FUNGAL CELLS

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Section: The Cytoskeletonmentioning

confidence: 97%

Fungal Morphogenesis

Lin

Alspaugh

Liu

et al. 2014

Cold Spring Harbor Perspectives in Medicine

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“…Other organisms may use similar autoinhibitory regulation of formins to modulate patterns of cell polarization: DAD-dependent regulation of a formin in Ashbya gossypii also affect the hyphal growth pattern of this filamentous fungus (Schmitz et al, 2006). Further investigation into these and other modes of formin regulation will reveal whether multiple activators also control formin autoinhibition in other species and provide a better understanding of the precise regulatory mechanisms underlying cell polarization and regulation of actin assembly.…”

Section: For3p and Regulation Of Bipolar Growthmentioning

confidence: 97%

Regulation of the Formin for3p by cdc42p and bud6p

Martin

Rincón

Basu

et al. 2007

MBoC

135

166

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Formins are conserved actin nucleators responsible for the assembly of diverse actin structures. Many formins are controlled through an autoinhibitory mechanism involving the interaction of a C-terminal DAD sequence with an N-terminal DID sequence. Here, we show that the fission yeast formin for3p, which mediates actin cable assembly and polarized cell growth, is regulated by a similar autoinhibitory mechanism in vivo. Multiple sites govern for3p localization to cell tips. The localization and activity of for3p are inhibited by an intramolecular interaction of divergent DAD and DID-like sequences. A for3p DAD mutant expressed at endogenous levels produces more robust actin cables, which appear to have normal organization and dynamics. We identify cdc42p as the primary Rho GTPase involved in actin cable assembly and for3p regulation. Both cdc42p, which binds at the N terminus of for3p, and bud6p, which binds near the C-terminal DAD-like sequence, are needed for for3p localization and full activity, but a mutation in the for3p DAD restores for3p localization and other phenotypes of cdc42 and bud6 mutants. In particular, the for3p DAD mutation suppresses the bipolar growth (NETO) defect of bud6⌬ cells. These findings suggest that cdc42p and bud6p activate for3p by relieving autoinhibition. INTRODUCTIONFormins are key regulators of the actin cytoskeleton and form a large family conserved in all eukaryotes Faix and Grosse, 2006). These proteins are necessary for the formation of numerous actin structures, including stress fibers, filopodia, cytokinetic actin rings, junctional actin structures, or actin cables. The proper regulation of formins is likely to be critical for cellular processes such as cell migration, cytokinesis, cell adhesion, and cell polarity.A well characterized biochemical activity of formins is to nucleate and elongate linear actin filaments Sagot et al., 2002b;Kovar et al., 2003;Li and Higgs, 2003;Moseley et al., 2004). This activity occurs through the formin-homology (FH) 2 domain, which dimerizes to form a doughnut-shaped structure containing multiple actin-binding sites in its core Otomo et al., 2005b). This dimer is thought to stabilize otherwise unstable intermediates in the assembly of new actin filaments, and it binds processively to the fast-elongating barbed end of existing actin filaments (Pring et al., 2003;Kovar and Pollard, 2004).The adjacent FH1 domain binds profilin-actin and helps accelerate the elongation of actin filaments (Chang et al., 1997;Evangelista et al., 1997;Watanabe et al., 1997;Romero et al., 2004;Kovar et al., 2006). The budding yeast formin Bni1p also binds the actin monomer-binding protein Bud6p, which, similar to profilin, stimulates the activity of the FH2 domain (Moseley and Goode, 2005). In addition to their activity in actin filament nucleation and elongation, some formins have been suggested to also function in actin bundling and severing, further contributing to the remodeling of actin structures (Harris et al., 2004Moseley and Goode, 2005;Harris et al., 2006...

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“…Oligonucleotide primers are listed in Table 3. Plasmid isolation from yeast and sequencing were performed as described in Schmitz et al (2006). A. gossypii deletion mutants were generated using the PCR-based, one-step gene targeting approach with nonhomologous selection markers (McElver and Weber, 1992;Baudin et al, 1993;Wach, 1996;Wendland et al, 2000).…”

Section: Plasmid and Strain Constructionmentioning

confidence: 99%

AgSwe1p Regulates Mitosis in Response to Morphogenesis and Nutrients in MultinucleatedAshbya gossypiiCells

Helfer

Gladfelter

2006

MBoC

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Nuclei in the filamentous, multinucleated fungus Ashbya gossypii divide asynchronously. We have investigated what internal and external signals spatially direct mitosis within these hyphal cells. Mitoses are most common near cortical septin rings found at growing tips and branchpoints. In septin mutants, mitoses are no longer concentrated at branchpoints, suggesting that the septin rings function to locally promote mitosis near new branches. Similarly, cells lacking AgSwe1p kinase (a Wee1 homologue), AgHsl1p (a Nim1-related kinase), and AgMih1p phosphatase (the Cdc25 homologue that likely counteracts AgSwe1p activity) also have mitoses distributed randomly in the hyphae as opposed to at branchpoints. Surprisingly, however, no phosphorylation of the CDK tyrosine 18 residue, the conserved substrate of Swe1p kinases, was detected in normally growing cells. In contrast, abundant CDK tyrosine phosphorylation was apparent in starving cells, resulting in diminished nuclear density. This starvation-induced CDK phosphorylation is AgSwe1p dependent, and overexpressed AgSwe1p is sufficient to delay nuclei even in rich nutrient conditions. In starving cells lacking septins or AgSwe1p negative regulators, the nuclear density is further diminished compared with wild type. We have generated a model in which AgSwe1p may regulate mitosis in response to cell intrinsic morphogenesis cues and external nutrient availability in multinucleated cells.

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From Function to Shape: A Novel Role of a Formin in Morphogenesis of the FungusAshbya gossypii

Cited by 64 publications

References 77 publications

Fungal Morphogenesis

Fungal Morphogenesis

Regulation of the Formin for3p by cdc42p and bud6p

AgSwe1p Regulates Mitosis in Response to Morphogenesis and Nutrients in MultinucleatedAshbya gossypiiCells

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