Association of Villin with Phosphatidylinositol 4,5-Bisphosphate Regulates the Actin Cytoskeleton

Kumar, Narendra; Zhao, Peilin; Tomar, Alok; Galea, Charles; Khurana, Seema

doi:10.1074/jbc.m308878200

Cited by 76 publications

(108 citation statements)

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“…3 Also unlike gelsolin, villin can assemble as well as disassemble actin filaments. Villin is also a phospholipid-binding protein that binds phosphatidylinositol 4,5-bisphosphate with very high affinity (53). We suggest that these properties of villin could determine its anti-apoptotic function.…”

Section: Discussionmentioning

confidence: 99%

A Novel Role for Villin in Intestinal Epithelial Cell Survival and Homeostasis

Wang

Srinivasan

Siddiqui

et al. 2008

Journal of Biological Chemistry

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Apoptosis is a key regulator for the normal turnover of the intestinal mucosa, and abnormalities associated with this function have been linked to inflammatory bowel disease and colorectal cancer. Despite this, little is known about the mechanism(s) mediating intestinal epithelial cell apoptosis. Villin is an actin regulatory protein that is expressed in every cell of the intestinal epithelium as well as in exocrine glands associated with the gastrointestinal tract. In this study we demonstrate for the first time that villin is an epithelial cell-specific anti-apoptotic protein. Absence of villin predisposes mice to dextran sodium sulfate-induced colitis by promoting apoptosis. To better understand the cellular and molecular mechanisms of the anti-apoptotic function of villin, we overexpressed villin in the Madin-Darby canine kidney Tet-Off epithelial cell line to demonstrate that expression of villin protects cells from apoptosis by maintaining mitochondrial integrity thus inhibiting the activation of caspase-9 and caspase-3. Furthermore, we report that the anti-apoptotic response of villin depends on activation of the pro-survival proteins, phosphatidylinositol 3-kinase and phosphorylated Akt. The results of our studies shed new light on the previously unrecognized function of villin in the regulation of apoptosis in the gastrointestinal epithelium.

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Section: Discussionmentioning

confidence: 99%

A Novel Role for Villin in Intestinal Epithelial Cell Survival and Homeostasis

Wang

Srinivasan

Siddiqui

et al. 2008

Journal of Biological Chemistry

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“…Similarly, the ForC GBD showed significant spectral changes only if the DPC concentration was well above the CMC, and the presence of the negatively charged lipids PIP345 and PIP45 lowered the micelle concentration necessary to induce structural rearrangements. PIP45-induced conformational changes have further been described for other actinbinding proteins, such as profilin (67), gelsolin (56), villin (68), and Talin (34). Future studies are required to identify binding partners of the GBD and other regions of ForC that will help to clarify whether and how ForC is regulated by a GTPase or other signaling proteins.…”

Section: Discussionmentioning

confidence: 99%

Structure, Dynamics, Lipid Binding, and Physiological Relevance of the Putative GTPase-binding Domain of Dictyostelium Formin C

Dames

Junemann

Sass

et al. 2011

Journal of Biological Chemistry

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Dictyostelium Formin C (ForC) is involved in the regulation of local actin cytoskeleton reorganization (e.g. during cellular adhesion or migration). ForC contains formin homology 2 and 3 (FH2 and -3) domains and an N-terminal putative GTPase-binding domain (GBD) but lacks a canonical FH1 region. To better understand the role of the GBD, its structure, dynamics, lipid-binding properties, and cellular functions were analyzed by NMR and CD spectroscopy and by in vivo fluorescence microscopy. Moreover, the program CS-Rosetta was tested for the structure prediction based on chemical shift data only. The ForC GBD adopts an ubiquitinlike ␣/␤-roll fold with an unusually long loop between ␤-strands 1 and 2. Based on the lipid-binding data, the presence of DPC micelles induces the formation of ␣-helical secondary structure and a rearrangement of the tertiary structure. Lipid-binding studies with a mutant protein and a peptide suggest that the ␤1-␤2 loop is not relevant for these conformational changes. Whereas small amounts of negatively charged phosphoinositides (1,2-dioctanoyl-sn-glycero-3-(phosphoinositol 4,5-bisphosphate) and 1,2-dihexanoyl-sn-glycero-3-(phosphoinositol 3,4,5-trisphosphate)) lower the micelle concentration necessary to induce the observed spectral changes, other negatively charged phospholipids (1,2-dihexanoyl-sn-glycero-3-(phospho-L-serine) and 1,2-dihexanoyl-snglycero-3-phospho-(1 -rac-glycerol)) had no such effect. Interestingly, bicelles and micelles composed of diacylphosphocholines had no effect on the GBD structure. Our data suggest a model in which part of the large positively charged surface area of the GBD mediates localization to specific membrane patches, thereby regulating interactions with signaling proteins. Our cellular localization studies show that both the GBD and the FH3 domain are required for ForC targeting to cell-cell contacts and early phagocytic cups and macropinosomes.Formins are widely expressed multidomain proteins that regulate the spatial and temporal organization of the actin and microtubule cytoskeleton, thereby affecting important cellular functions, such as cytokinesis and cell-cell adhesion (1-3). The defining element is the ϳ400-amino acid-encompassing "formin homology 2" (FH2) 2 domain that can tightly associate with the barbed end of elongating actin filaments (4). In nearly all formins, the FH2 domain is preceded by a prolinerich "formin homology 1" (FH1) region that varies in length and the number of binding sites for profilin and that is used to recruit profilin-actin complexes for filament elongation. The influence of the FH2 domain on the rate of filament elongation depends on the length and composition of the FH1 region and the connecting linker (2, 4, 5). Most formins contain additional regulatory domains. The N-terminal "formin homology 3" (FH3) domain mediates interactions with autoinhibitory regulatory elements in the C terminus as well as with other formin regulators. The FH3 domain can be further divided into functional subdomains, such as an armadill...

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“…We have previously shown that mutation of this single residue, R138 within the PB2 domain of villin (R138A) results in significant (B85%) loss of PIP 2 binding by this site. 15 However, mutation of R138 (R138A) has a negligible effect on the actin-severing activity of villin. 16 Consistent with our previous findings, a significant increase in the number of apoptotic VIL/NULL cells was noted 5 h post-CPT treatment, whereas no significant change in cell death was noted in VIL/WT cells (Figure 2a, Supplementary Figure 1B).…”

Section: Villin Inhibits Apoptosis By Preserving Actin Dynamicsmentioning

confidence: 99%

“…16 Mutation of three basic residues R138A, K145A and R146A (VIL/RKR) within the PB2 domain of villin also results in the complete loss of actin severing by villin and PIP 2 binding by this domain of villin. 15,16 To distinguish between the overlapping PIP 2 and actin-severing functions of villin domain PB2, we generated an additional mutant VIL/R138A. We have previously shown that mutation of this single residue, R138 within the PB2 domain of villin (R138A) results in significant (B85%) loss of PIP 2 binding by this site.…”

Section: Villin Inhibits Apoptosis By Preserving Actin Dynamicsmentioning

confidence: 99%

“…Functional characterization of these mutants, including their effect on actin kinetics have been described in our previous studies. 15 PB2 represents an overlapping PIP 2 and F-actin side-binding site that regulates actin severing by villin. 16 Mutation of three basic residues R138A, K145A and R146A (VIL/RKR) within the PB2 domain of villin also results in the complete loss of actin severing by villin and PIP 2 binding by this domain of villin.…”

Section: Villin Inhibits Apoptosis By Preserving Actin Dynamicsmentioning

confidence: 99%

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Actin reorganization as the molecular basis for the regulation of apoptosis in gastrointestinal epithelial cells

et al. 2012

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The gastrointestinal (GI) epithelium is a rapidly renewing tissue in which apoptosis represents part of the overall homeostatic process. Regulation of apoptosis in the GI epithelium is complex with a precise relationship between cell position and apoptosis. Apoptosis occurs spontaneously and in response to radiation and cytotoxic drugs at the base of the crypts. By contrast, the villus epithelial cells are extremely resistant to apoptosis. The molecular mechanism underlying this loss of function of villus epithelial cells to undergo apoptosis shortly after their exit from the crypt is unknown. In this study we demonstrate for the first time, that deletion of two homologous actin-binding proteins, villin and gelsolin renders villus epithelial cells extremely sensitive to apoptosis. Ultrastructural analysis of the villin-gelsolin À/À double-knockout mice shows an abnormal accumulation of damaged mitochondria demonstrating that villin and gelsolin function on an early step in the apoptotic signaling at the level of the mitochondria. A characterization of functional and ligand-binding mutants demonstrate that regulated changes in actin dynamics determined by the actin severing activities of villin and gelsolin are required to maintain cellular homeostasis. Our study provides a molecular basis for the regulation of apoptosis in the GI epithelium and identifies cell biological mechanisms that couple changes in actin dynamics to apoptotic cell death.

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Association of Villin with Phosphatidylinositol 4,5-Bisphosphate Regulates the Actin Cytoskeleton

Cited by 76 publications

References 84 publications

A Novel Role for Villin in Intestinal Epithelial Cell Survival and Homeostasis

A Novel Role for Villin in Intestinal Epithelial Cell Survival and Homeostasis

Structure, Dynamics, Lipid Binding, and Physiological Relevance of the Putative GTPase-binding Domain of Dictyostelium Formin C

Actin reorganization as the molecular basis for the regulation of apoptosis in gastrointestinal epithelial cells

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