The Core FH2 Domain of Diaphanous-Related Formins Is an Elongated Actin Binding Protein that Inhibits Polymerization

Shimada, Akira; Nyitrai, Miklós; Vetter, Ingrid R.; Kühlmann, Dorothee; Bugyi, Beáta; Narumiya, Shuh; Geeves, Michael A.; Wittinghofer, Alfred

doi:10.1016/s1097-2765(04)00059-0

Cited by 137 publications

(179 citation statements)

References 41 publications

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“…Actin nucleation is mediated by the conserved formin homology domain FH2. As found by analyzing the crystal structures of the mouse formin, mDIA, and the yeast formin, ScBni1p, the core of the FH2 domain seems to have actin binding capacity, whereas adjacent amino acids are necessary for oligomerization and gain of polymerization capability (Shimada et al, 2004;Xu et al, 2004). A subclass of formins, the so-called diaphanous related formins (DRFs), are defined by two properties: First, they are activated when a GTP-bound Rho-type protein interacts with their amino terminus (Kohno et al, 1996;Evangelista et al, 1997;Imamura et al, 1997;Watanabe et al, 1997;Habas et al, 2001).…”

Section: Introductionmentioning

confidence: 98%

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

Schmitz

Kaufmann

Köhli

et al. 2006

MBoC

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Morphogenesis of filamentous ascomycetes includes continuously elongating hyphae, frequently emerging lateral branches, and, under certain circumstances, symmetrically dividing hyphal tips. We identified the formin AgBni1p of the model fungus Ashbya gossypii as an essential factor in these processes. AgBni1p is an essential protein apparently lacking functional overlaps with the two additional A. gossypii formins that are nonessential. Agbni1 null mutants fail to develop hyphae and instead expand to potato-shaped giant cells, which lack actin cables and thus tip-directed transport of secretory vesicles. Consistent with the essential role in hyphal development, AgBni1p locates to tips, but not to septa. The presence of a diaphanous autoregulatory domain (DAD) indicates that the activation of AgBni1p depends on Rho-type GTPases. Deletion of this domain, which should render AgBni1p constitutively active, completely changes the branching pattern of young hyphae. New axes of polarity are no longer established subapically (lateral branching) but by symmetric divisions of hyphal tips (tip splitting). In wild-type hyphae, tip splitting is induced much later and only at much higher elongation speed. When GTP-locked Rho-type GTPases were tested, only the young hyphae with mutated AgCdc42p split at their tips, similar to the DAD deletion mutant. Two-hybrid experiments confirmed that AgBni1p interacts with GTP-bound AgCdc42p. These data suggest a pathway for transforming one axis into two new axes of polar growth, in which an increased activation of AgBni1p by a pulse of activated AgCdc42p stimulates additional actin cable formation and tip-directed vesicle transport, thus enlarging and ultimately splitting the polarity site.

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Section: Introductionmentioning

confidence: 98%

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

Schmitz

Kaufmann

Köhli

et al. 2006

MBoC

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“…Its NH2-terminal context is the Formin-Homology-1 (FH1) domain, a proline-rich domain that binds profilin [7,10,11]. FH2 alone is found to inhibit actin polymerization [12] which cannot be reversed by adding profilins [13]. By adding the FH1 domain, FH1-FH2 accelerates profilin-actin polymerization up to 15-fold the rate of free barbed ends [14].…”

Section: Introductionmentioning

confidence: 99%

A cooperative jack model of random coil‐to‐elongation transition of the FH1 domain by profilin binding explains formin motor behavior in actin polymerization

et al. 2014

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a b s t r a c tFilopodia are essential for the development of neuronal growth cones, cell polarity and cell migration. Their protrusions are powered by the polymerization of actin filaments linked to the plasma membrane, catalyzed by formin proteins. The acceleration of polymerization depends on the number of profilin-actins binding with the formin-FH1 domain. Biophysical characterization of the disordered formin-FH1 domain remains a challenge. We analyzed the conformational distribution of the diaphanous-related formin mDia1-FH1 bound with one to six profilins. We found a coil-to-elongation transition in the FH1 domain. We propose a cooperative ''jack'' model for the Formin-Homology-1 (FH1) domain of formins stacked by profilin-actins.

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“…Essential to these properties is the formin homology 2 (FH2) 1 domain, a 400-residue region generally found in the C-terminal half of the protein. Biochemical and structural studies show that the FH2 domain is dimeric for several formins (10,13,14), although longer constructs of the budding yeast formin, Bni1p, can tetramerize (6). Mammals possess 15 formin genes, in seven distinct phylogenetic groups (15).…”

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confidence: 99%

Dissecting Requirements for Auto-inhibition of Actin Nucleation by the Formin, mDia1

Higgs

2005

Journal of Biological Chemistry

163

192

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The mammalian formin, mDia1, is an actin nucleation factor. Experiments in cells and in vitro show that the N-terminal region potently inhibits nucleation by the formin homology 2 (FH2) domain-containing C terminus and that RhoA binding to the N terminus partially relieves this inhibition. Cellular experiments suggest that potent inhibition depends upon the presence of the diaphanous auto-regulatory domain (DAD) C-terminal to FH2. In this study, we examine in detail the N-terminal and C-terminal regions required for this inhibition and for RhoA relief. Limited proteolysis of an N-terminal construct from residues 1-548 identifies two stable truncations: 129 -548 and 129 -369. Analytical ultracentrifugation suggests that 1-548 and 129 -548 are dimers, whereas 129 -369 is monomeric. All three N-terminal constructs inhibit nucleation by the full C terminus. Although inhibition by 1-548 is partially relieved by RhoA, inhibition by 129 -548 or 129 -369 is RhoA-resistant. At the C terminus, DAD deletion does not affect nucleation but decreases inhibitory potency of 1-548 by 20,000-fold. Synthetic DAD peptide binds both 1-548 and 129 -548 with similar affinity and partially relieves nucleation inhibition. C-terminal constructs are stable dimers. Our conclusions are as follows: 1) DAD is an affinity-enhancing motif for auto-inhibition; 2) an N-terminal domain spanning residues 129 -369 (called DID for diaphanous inhibitory domain) is sufficient for autoinhibition; 3) a dimerization region C-terminal to DID increases the inhibitory ability of DID ; and 4) DID alone is not sufficient for RhoA relief of auto-inhibition, suggesting that sequences N-terminal to DID are important to RhoA binding. An additional finding is that FH2 domain-containing constructs of mDia1 and mDia2 lose >75% nucleation activity upon freeze-thaw.Formin proteins are emerging as regulators of many cellular actin-based structures (1, 2). Biochemically, formins exert several effects on actin polymerization dynamics, including acceleration of filament nucleation from monomers, inhibition of barbed end elongation rate, inhibition of complete barbed end capping by heterodimeric capping protein, and filament severing (3-10). These in vitro activities are generally considered to result from the ability of formins to bind at or near the filament barbed end and to move processively with the barbed end as it elongates (11, 12). Essential to these properties is the formin homology 2 (FH2) 1 domain, a 400-residue region generally found in the C-terminal half of the protein. Biochemical and structural studies show that the FH2 domain is dimeric for several formins (10,13,14), although longer constructs of the budding yeast formin, Bni1p, can tetramerize (6). Mammals possess 15 formin genes, in seven distinct phylogenetic groups (15). For one mammalian formin, mDia1, the mechanisms regulating effects on actin have begun to be elucidated. The in vitro nucleation activity of the FH2-containing C terminus of mDia1 is inhibited potently by inclusion of a separate polyp...

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The Core FH2 Domain of Diaphanous-Related Formins Is an Elongated Actin Binding Protein that Inhibits Polymerization

Cited by 137 publications

References 41 publications

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

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

A cooperative jack model of random coil‐to‐elongation transition of the FH1 domain by profilin binding explains formin motor behavior in actin polymerization

Dissecting Requirements for Auto-inhibition of Actin Nucleation by the Formin, mDia1

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