SnapShot: Actin Regulators II

Siripala, Anosha D.; Welch, Matthew D.

doi:10.1016/j.cell.2007.02.021

Cited by 14 publications

(9 citation statements)

References 20 publications

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“…Thymosin β4 and β10 are known to bind monomeric actin (G-actin) and regulate actin polymerization (F-actin). Controlled actin polymerization is essential for normal cytoskeletal function [47, 48]. The protein detected by MALDI FTICR IMS at m/z 5,636.074 was identified as mitochondrial ATP synthase subunit ε (ATPase-ε, −2.3 ppm).…”

Section: Resultsmentioning

confidence: 99%

MALDI FTICR IMS of Intact Proteins: Using Mass Accuracy to Link Protein Images with Proteomics Data

Spraggins

Rizzo

Moore

et al. 2015

J. Am. Soc. Mass Spectrom.

120

139

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MALDI imaging mass spectrometry is a highly sensitive and selective tool used to visualize biomolecules in tissue. However, identification of detected proteins remains a difficult task. Indirect identifications strategies have been limited by insufficient mass accuracy to confidently link ion images to proteomics data. Here we demonstrate the capabilities of MALDI FTICR MS for imaging intact proteins. MALDI FTICR IMS provides an unprecedented combination of mass resolving power (∼75,000 at m/z 5,000) and accuracy (<5 ppm) for proteins up to ∼12 kDa enabling identification based on correlation with LC-MS/MS proteomics data. Analysis of rat brain tissue was performed as a proof-of-concept highlighting the capabilities of this approach by imaging and identifying a number of proteins including N-terminally acetylated Thymosin β4 (m/z 4,963.502, 0.6 ppm) and ATP Synthase subunit ε (m/z 5,636.074, −2.3 ppm). MALDI FTICR IMS was also used to differentiate a series of oxidation products of S100A8 (m/z 10,164.03, −2.1 ppm), a subunit of the heterodimer calprotectin, in kidney tissue from mice infected with Staphylococcus aureus. S100A8 – M37O/C42O3 (m/z 10228.00, −2.6 ppm) was found to co-localize with bactierial microcolonies at the center of infectious foci. The ability of MALDI FTICR IMS to distinguish S100A8 modifications is critical to understanding calprotectin’s roll in nutritional immunity.

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Section: Resultsmentioning

confidence: 99%

MALDI FTICR IMS of Intact Proteins: Using Mass Accuracy to Link Protein Images with Proteomics Data

Spraggins

Rizzo

Moore

et al. 2015

J. Am. Soc. Mass Spectrom.

120

139

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“…More than 100 actin‐binding proteins have established roles in the temporal and spatial modulation of actin filaments, with ∼300 binding proteins reported in total [Dos Remedios et al, ; Siripala and Welch, ; http://www.bms.ed.ac.uk/research/others/smaciver/encyclop/encycloABP.htm]. An individual actin‐binding protein may alter the kinetics of actin polymerization by nucleating filaments, by capping filaments at either their pointed or barbed ends, by cross‐linking filaments to form bundles and networks, or by disassembling filaments and networks through depolymerization or severing activities.…”

Section: Introductionmentioning

confidence: 99%

Gelsolin: The tail of a molecular gymnast

et al. 2013

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Gelsolin superfamily members are Ca 21 -dependent, multidomain regulators of the actin cytoskeleton. Calcium binding activates gelsolin by inducing molecular gymnastics (large-scale conformational changes) that expose actin interaction surfaces by releasing a series of latches. A specialized tail latch has distinguished gelsolin within the superfamily. Active gelsolin exhibits actin filament severing and capping, and actin monomer sequestering activities. Here, we analyze a combination of sequence, structural, biophysical and biochemical data to assess whether the molecular plasticity, regulation and actinrelated properties of gelsolin are also present in other superfamily members. We conclude that all members of the superfamily will be able to transition between a compact conformation and a more open form, and that most of these open forms will interact with actin. Supervillin, which lacks the severing domain 1 and the F-actin binding-site on domain 2, is the clear exception. Eight calcium-binding sites are absolutely conserved in gelsolin, adseverin, advillin and villin, and compromised to increasing degrees in CapG, villin-like protein, supervillin and flightless I. Advillin, villin and supervillin each contain a potential tail latch, which is absent from CapG, adseverin and flightless I, and ambiguous in villin-like protein. Thus, calcium regulation will vary across the superfamily. Potential novel isoforms of the superfamily suggest complex regulation at the gene, transcript and protein levels. We review animal, clinical and cellular data that illuminate how the regulation of molecular flexibility in gelsolin-like proteins permits cells to exploit the force generated from actin polymerization to drive processes such as cell movement in health and disease. V C 2013 Wiley Periodicals, Inc.

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“…In cells, actin is found in monomeric form (G-actin) and in filamentous form (F-actin). Most of actin’s roles are related to its ability to form filaments and networks, which is tightly controlled through numerous actin-modifying proteins (1, 2). These include proteins involved in polymerization and depolymerization of actin filaments, nucleators, and severing proteins as well as proteins involved in organizing filaments such as bundling proteins or filament crosslinkers (3, 4).…”

Section: Introductionmentioning

confidence: 99%

The Natural Product Cucurbitacin E Inhibits Depolymerization of Actin Filaments

et al. 2012

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Although small molecule actin modulators have been widely used as research tools, only one cell permeable small molecule inhibitor of actin depolymerization (jasplakinolide) is commercially available. We report that the natural product cucurbitacin E inhibits actin depolymerization and show that its mechanism of action is different from jasplakinolide. In assays using pure fluorescently labeled actin, cucurbitacin E specifically affected depolymerization without affecting polymerization. It inhibited actin depolymerization at sub-stoichiometric concentrations up to 1:6 cucurbitacin:actin E. Cucurbitacin E specifically binds to filamentous actin (F-actin) forming a covalent bond at residue Cys257, but not to monomeric actin (G-actin). Based on its compatibility with phalloidin staining, we show that cucurbitacin E occupies a different binding site on actin filaments. Using loss of fluorescence after localized photoactivation, we found that cucurbitacin E inhibited actin depolymerization in live cells. Cucurbitacin E is a widely available plant-derived natural product, making it a useful tool to study actin dynamics in cells and actin-based processes such as cytokinesis.

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SnapShot: Actin Regulators II

Cited by 14 publications

References 20 publications

MALDI FTICR IMS of Intact Proteins: Using Mass Accuracy to Link Protein Images with Proteomics Data

MALDI FTICR IMS of Intact Proteins: Using Mass Accuracy to Link Protein Images with Proteomics Data

Gelsolin: The tail of a molecular gymnast

The Natural Product Cucurbitacin E Inhibits Depolymerization of Actin Filaments

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