Formins direct Arp2/3-independent actin filament assembly to polarize cell growth in yeast

Evangelista, Marie; Pruyne, David; Amberg, David C.; Boone, Charles; Bretscher, Aanthony

doi:10.1038/ncb718

Cited by 429 publications

(395 citation statements)

References 53 publications

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“…Formin-2 belongs to the formin family of actin nucleators defined by their conserved FH1 and FH2 domains. In contrast to the Arp2/3 complex, which binds to pre-existing filaments and nucleates new actin filament to form a Y-shaped branch [Pantaloni et al, 2001;Pollard and Cooper, 2009], formin proteins nucleate actin and processively binds to and facilitates the elongation of the barbed ends to generate long and straight actin filaments [Evangelista et al, 2002;Sagot et al, 2002;Higgs and Peterson, 2005]. As a member of the formin family nucleators, mouse formin-2 has been found to be expressed exclusively in oocytes and the central nervous system [Leader and Leder, 2000;Leader et al, 2002].…”

Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

2012

Cytoskeleton

104

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Mammalian oocyte maturation involves two successive rounds of extremely asymmetric cell divisions (known as polar body extrusion) to generate a functional haploid egg. Successful polar body extrusion relies on establishment of an asymmetric spindle position and cortical polarity. Decades of studies using mouse oocytes as a model have revealed critical roles for a dynamic actin cytoskeleton in this process. Here, we review the contribution of actin to the critical events during oocyte meiotic cell divisions with an emphasis on recent advances in understanding the underlying molecular and physical mechanisms. V C 2012 Wiley Periodicals, Inc

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Section: Spindle Migration: Where and How The Force Is Generatedmentioning

confidence: 99%

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

2012

Cytoskeleton

104

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“…We wished to examine whether these localizations impart differences in the distribution of the actin filaments assembled by the two isoforms. However, overexpression of either formin alters actin organization and cell morphology (Kamei et al, 1998;Evangelista et al, 2002;Sagot et al, 2002a). To avoid this complication, we observed the distribution of the formins and formin-dependent actin filaments in cells that expressed Bni1p and Bnr1p at endogenous levels.…”

Section: Bni1p and Bnr1p Maintain Distinct Sets Of Actin Cablesmentioning

confidence: 99%

“…A COOHterminal GFP-fusion of full-length Bnr1p expressed from the BNR1 locus also displayed a localization in agreement with previous overexpression studies ( Kamei et al, 1998), showing a polarized distribution in very few unbudded cells (5% of unbudded cells), but a ring of fluorescence around the neck of cells with buds of all sizes ( Figures 1C and S1A). In yeast, formin-dependent actin filaments can be distinguished from the Arp2/3 complex-dependent filaments by their association with the F-actin binding protein tropomyosin, encoded by the TPM1 and TPM2 genes (Liu and Bretscher, 1989;Pruyne et al, 1998;Evangelista et al, 2002;Sagot et al, 2002a;Tolliday et al, 2002). To determine whether Bni1p or Bnr1p make distinct contributions to assembling these filaments, we examined Tpm1p distribution in wild-type yeast and strains lacking Bni1p (bni1⌬/bni1⌬) or Bnr1p (bnr1⌬/bnr1⌬) (Figure 1, C and D).…”

Section: Bni1p and Bnr1p Maintain Distinct Sets Of Actin Cablesmentioning

confidence: 99%

“…Other actin nucleators, particularly the Arp2/3 complex, play no apparent role in cable or cytokinetic ring assembly in budding yeast (Winter et al, 1999;Evangelista et al, 2002;Tolliday et al, 2002), suggesting the formins might be in vivo nucleators for these actin filaments. However, the loss of Bni1p or Bnr1p individually results in different phenotypes.…”

Section: Introductionmentioning

confidence: 98%

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Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Pruyne

Gao

et al. 2004

MBoC

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Bud growth in yeast is guided by myosin-driven delivery of secretory vesicles from the mother cell to the bud. We find transport occurs along two sets of actin cables assembled by two formin isoforms. The Bnr1p formin assembles cables that radiate from the bud neck into the mother, providing a stable mother-bud axis. These cables also depend on septins at the neck and are required for efficient transport from the mother to the bud. The Bni1p formin assembles cables that line the bud cortex and target vesicles to varying locations in the bud. Loss of these cables results in morphological defects as vesicles accumulate at the neck. Assembly of these cables depends on continued polarized secretion, suggesting vesicular transport provides a positive feedback signal for Bni1p activation, possibly by rho-proteins. By coupling different formin isoforms to unique cortical landmarks, yeast uses common cytoskeletal elements to maintain stable and dynamic axes in the same cell. INTRODUCTIONProper cell polarization requires a balance between dynamism and stability. Persistent systems, such as the apical and basolateral domains of epithelial cells, show a higher stability than flexible systems, such as cells undergoing chemotaxis. However, both types can use similar cytoskeletal components, so an important task in understanding the control of polarity is to identify features that influence persistence, and how those features integrate with the core cytoskeletal machinery providing the physical expression of polarity.The process of bud growth of the yeast Saccharomyces cerevisiae provides a model for examining the control of polarity (for reviews, see Bretscher, 2003;Chang and Peter, 2003). Secretory organelles, such as the Golgi and endoplasmic reticulum, are distributed throughout the bud and mother cell, whereas post-Golgi secretory vesicles concentrate at discrete growth sites at the cell cortex. These vesicles are guided to these sites along what are essentially two axes of polarity: a stable axis directing traffic from the mother into the bud, and a dynamic axis that fine-tunes delivery from the bud neck to specific regions in the bud, sending vesicles first to the small bud tip, then to the entire bud surface, and finally back toward the neck during mother/daughter separation. On delivery to these locations, post-Golgi vesicles fuse with the cell surface to promote localized cell expansion.Two class-V myosins, with heavy chains encoded by MYO2 (Johnston et al., 1991) and MYO4 (Haarer et al., 1994), propel cellular components, including vesicles, organelles, mRNAs, and microtubules, from the mother into the bud during growth and organelle segregation. The myosins move along cables of actin filaments that radiate throughout the cell in arrays oriented toward growth sites (Adams and Pringle, 1984;Kilmartin and Adams, 1984).Assembly of these cables depends on two formin homologues, Bni1p and Bnr1p (Evangelista et al., 2002;Sagot et al., 2002a), members of a family of cytoskeletal regulatory proteins defined by conserved fo...

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“…In contrast, cells of uninfected root tissue predominantly exhibit longitudinal AF arrays . The potential ability of AtFH6 to trigger a cytoskeletal reorganization was assessed by functional complementation of a yeast mutant deficient for the BNI1p and BNR1p formins, which both control the assembly of yeast actin bundles [Evangelista et al, 2002;Sagot et al, 2002]. Based on its ability to rescue the bin1Dbnr1D yeast mutant phenotype and on its localization at the plasma membrane, AtFH6 was proposed to be, at least partially, responsible for the assembly of the cortical actin bundles required for vesicle trafficking during the extensive plasma membrane and cell wall biogenesis [Favery et al, 2004].…”

Section: Forminsmentioning

confidence: 99%

Actin bundling in plants

Thomas

Tholl

Moes

et al. 2009

Cell Motil. Cytoskeleton

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Tight regulation of plant actin cytoskeleton organization and dynamics is crucial for numerous cellular processes including cell division, expansion and intracellular trafficking. Among the various actin regulatory proteins, actin-bundling proteins trigger the formation of bundles composed of several parallel actin filaments closely packed together. Actin bundles are present in virtually all plant cells, but their biological roles have rarely been addressed directly. However, decades of research in the plant cytoskeleton field yielded a bulk of data from which an overall picture of the functions supplied by actin bundles in plant cells emerges. Although plants lack several equivalents of animal actin-bundling proteins, they do possess major bundler classes including fimbrins, villins and formins. The existence of additional players is not excluded as exemplified by the recent characterization of plant LIM proteins, which trigger the formation of actin bundles both in vitro and in vivo. This apparent functional redundancy likely reflects the need for plant cells to engineer different types of bundles that act at different sub-cellular locations and exhibit specific function-related properties. By surveying information regarding the properties of plant actin bundles and their associated bundling proteins, the present review aims at clarifying why and how plants make actin bundles. Cell Motil. Cytoskeleton 66: 940-957, 2009. '

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Formins direct Arp2/3-independent actin filament assembly to polarize cell growth in yeast

Cited by 429 publications

References 53 publications

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

Actin cytoskeleton in cell polarity and asymmetric division during mouse oocyte maturation

Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Actin bundling in plants

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