Plant Actin-binding Protein SCAB1 Is Dimeric Actin Cross-linker with Atypical Pleckstrin Homology Domain

Zhang, Wei; Zhao, Yanping; Guo, Yan; Ye, Keqiong

doi:10.1074/jbc.m111.338525

Cited by 15 publications

(11 citation statements)

References 49 publications

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“…The N-terminal domain of the enzyme is primarily composed of extended loop regions around a core composed of a six ␤-strand meander that forms a two-layer ␤-sandwich. This domain most closely matches the immunoglobulin portion of the plant actin-binding protein SCAB1 (37). The C-terminal domain contains the potential catalytic domain and forms a mixed multilayer ␣-helix-␤-strand structure similar to the other EEP family members.…”

Section: Effects Of Pde12 Gene Inactivation On Viral Infection-thementioning

confidence: 76%

The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors

Wood

Bledsoe

Chai

et al. 2015

Journal of Biological Chemistry

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Background: PDE12 degrades 2Ј,5Ј-oligoadenylate, a second messenger involved in the antiviral action of interferon. Results: Inactivation of the PDE12 gene and novel inhibitors of the enzyme render cells resistant to more than one virus. Conclusion: PDE12 negatively regulates the innate immune response, and inhibitors of PDE12 have antiviral activity. Significance: PDE12 inhibitors have the potential to be broadly acting antiviral medicines.

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Section: Effects Of Pde12 Gene Inactivation On Viral Infection-thementioning

confidence: 76%

The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors

Wood

Bledsoe

Chai

et al. 2015

Journal of Biological Chemistry

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“…Coiled-coil-mediated protein interactions are involved in a variety of biological processes including vesicle-mediated transport, cellular membrane organization, cytokinesis, and chromosome segregation (39). Dimerization by formation of a coiled-coil either increases avidity for binding partners as in SCAB1 (40) or allosterically promotes formation of a structured domain conducive for binding, such as inducing formation of a voltage gated channel assembly (41). With Swallow, the LC8-promoted coiled-coil suggests an intriguing potential for further bivalency effects that could allosterically induce structural organization of the disordered N- and C-terminal domains, and thus underlie the essential role of LC8-Swallow interactions in bicoid localization.…”

Section: Discussionmentioning

confidence: 99%

Structural Features of LC8-Induced Self-Association of Swallow

et al. 2013

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Cell function depends on the collective activity of protein networks within which a few proteins, called hubs, participate in a large number of interactions. Dynein light chain LC8, first discovered as a subunit of the motor protein dynein, is considered to have a role broader than dynein and its participation in diverse systems fits the description of a hub. Among its partners is Swallow with which LC8 is essential for proper localization of bicoid mRNA at the anterior cortex of Drosophila oocytes. Why LC8 is essential in this process is not clear, but emerging evidence suggests that LC8 functions by promoting self-association and/or structural organization of its diverse binding partners. This work addresses the mechanistic and structural features of LC8-induced Swallow self-association distant from LC8 binding. Mutational design based on a hypothetical helical wheel, inter-monomer NOEs assigned to residues expected at interface positions and circular dichroism spectral characteristics indicate that the LC8-promoted dimer of Swallow is a coiled-coil. Secondary chemical shifts and 15N backbone relaxation identify the boundaries and distinguishing structural features of the coiled-coil. Thermodynamic analysis of Swallow polypeptides designed to decouple self-association from LC8 binding reveals that the higher binding affinity of the engineered bivalent Swallow is of purely entropic origin and that the linker separating the coiled-coil from the LC8 binding site remains disordered. We speculate that the LC8-promoted coiled-coil is critical for bicoid mRNA localization because it could induce structural organization of Swallow, which except for the central LC8-promoted coiled-coil is primarily disordered.

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“…Despite the frequent pairwise arrangement of their ABDs, some actin-bundling proteins undergo dimerization to crosslink actin filaments (Mimura and Asano, 1986;Thomas, 2012;Thomas et al, 2009). For instance, dimerization as a prerequisite for actin-bundling activity has been reported for members of the evolutionarily conserved villin and formin families and for the recently described, plant-specific SCAB1 protein (Chhabra and Higgs, 2006;George et al, 2007;Harris et al, 2004;Li and Higgs, 2005;Michelot et al, 2006;Michelot et al, 2005;Mimura and Asano, 1986;Xu et al, 2004;Yokota et al, 1998;Zhang et al, 2012). By contrast, fimbrins use the close proximity of their two ABDs to induce bundle formation and function as monomers in yeast, animals and plants (Klein et al, 2004;Nakano et al, 2001;Volkmann et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Live cell imaging approaches reveal actin cytoskeleton-induced self-association of the actin-bundling protein WLIM1

Hoffmann

Moes

Dieterle

et al. 2013

Journal of Cell Science

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Crosslinking of actin filaments into bundles is critical for the assembly/stabilization of specific cytoskeletal structures. Relatively little is known about the molecular mechanisms underlying actin bundle formation. The two LIM domain-containing (LIM) proteins define a novel and evolutionary-conserved family of actin bundlers whose actin-binding and -crosslinking activities primarily rely on their LIM domains. Using TIRF microscopy, we describe real-time formation of actin bundles induced by tobacco NtWLIM1 in vitro. We show that NtWLIM1 binds to single filaments and subsequently promotes their interaction and zippering into tight bundles of mixed polarity. NtWLIM1-induced bundles grew by both elongation of internal filaments and addition of preformed fragments at their extremities. Importantly, these data are highly consistent with the modes of bundle formation and growth observed in transgenic Arabidopsis plants expressing a GFP fused Arabidopsis AtWLIM1 protein. Using two complementary live cell imaging approaches, a close relationship between NtWLIM1 subcellular localization and self-association was established. Indeed, both BiFC and FLIM-FRET data revealed that, although unstable NtWLIM1 complexes can sporadically form in the cytosol, stable complexes concentrate along the actin cytoskeleton. Remarkably, the disruption of the actin cytoskeleton significantly impaired NtWLIM1 self-association. In addition, biochemical analyses support that F-actin facilitates the switch of purified recombinant NtWLIM1 from a monomeric to a di/oligomeric state. Based on our data we propose a model in which actin binding promotes the formation/stabilization of NtWLIM1 complexes, which in turn might drive the crosslinking of actin filaments.

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Plant Actin-binding Protein SCAB1 Is Dimeric Actin Cross-linker with Atypical Pleckstrin Homology Domain

Cited by 15 publications

References 49 publications

The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors

The Role of Phosphodiesterase 12 (PDE12) as a Negative Regulator of the Innate Immune Response and the Discovery of Antiviral Inhibitors

Structural Features of LC8-Induced Self-Association of Swallow

Live cell imaging approaches reveal actin cytoskeleton-induced self-association of the actin-bundling protein WLIM1

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