scholarly journals Mammalian Adenylyl Cyclase-associated Protein 1 (CAP1) Regulates Cofilin Function, the Actin Cytoskeleton, and Cell Adhesion

2013 ◽  
Vol 288 (29) ◽  
pp. 20966-20977 ◽  
Author(s):  
Haitao Zhang ◽  
Pooja Ghai ◽  
Huhehasi Wu ◽  
Changhui Wang ◽  
Jeffrey Field ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton ◽  
Hela Cells ◽  
Actin Polymerization ◽  
Actin Dynamics ◽  
Ras Signaling ◽  
Filamentous Actin ◽  
Camp Pathway

CAP (adenylyl cyclase-associated protein) was first identified in yeast as a protein that regulates both the actin cytoskeleton and the Ras/cAMP pathway. Although the role in Ras signaling does not extend beyond yeast, evidence supports that CAP regulates the actin cytoskeleton in all eukaryotes including mammals. In vitro actin polymerization assays show that both mammalian and yeast CAP homologues facilitate cofilin-driven actin filament turnover. We generated HeLa cells with stable CAP1 knockdown using RNA interference. Depletion of CAP1 led to larger cell size and remarkably developed lamellipodia as well as accumulation of filamentous actin (F-actin). Moreover, we found that CAP1 depletion also led to changes in cofilin phosphorylation and localization as well as activation of focal adhesion kinase (FAK) and enhanced cell spreading. CAP1 forms complexes with the adhesion molecules FAK and Talin, which likely underlie the cell adhesion phenotypes through inside-out activation of integrin signaling. CAP1-depleted HeLa cells also had substantially elevated cell motility as well as invasion through Matrigel. In summary, in addition to generating in vitro and in vivo evidence further establishing the role of mammalian CAP1 in actin dynamics, we identified a novel cellular function for CAP1 in regulating cell adhesion.

Effects of cadmium on the actin cytoskeleton in renal mesangial cells

2013 ◽  
Vol 91 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Douglas M. Templeton ◽  
Ying Liu
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Mesangial Cells ◽  
Focal Adhesions ◽  
Filamentous Actin ◽  
Human Mesangial Cells ◽  
Dependent Protein

We provide an overview of our studies on cadmium and the actin cytoskeleton in mesangial cells, from earlier work on the effects of Cd2+ on actin polymerization in vivo and in vitro, to a role of disruption or stabilization of the cytoskeleton in apoptosis and apoptosis-like death. More recent studies implicate cadmium-dependent association of gelsolin and the Ca2+/calmodulin-dependent protein kinase II (CaMK-II) with actin filaments in cytoskeletal effects. We also present previously unpublished data concerning cadmium and the disruption of focal adhesions. The work encompasses studies on rat, mouse, and human mesangial cells. The major conclusions are that Cd2+ acts independently of direct effects on cellular Ca2+ levels to nevertheless activate Ca2+-dependent proteins that shift the actin polymerization–depolymerization in favour of depolymerization. Cadmium-dependent translocation of CaMK-IIδ, gelsolin, and a 50 kDa gelsolin cleavage fragment to the filamentous (F-)actin cytoskeleton appear to be involved. An intact filamentous actin cytoskeleton is required to initiate apoptotic and apoptotic-like death, but F-actin depolymerization is an eventual result.

scholarly journals THz irradiation inhibits cell division by affecting actin dynamics

2021 ◽  
Author(s):  
shota yamazaki ◽  
Yuya Ueno ◽  
Ryosuke Hosoki ◽  
Takanori Saito ◽  
Toshitaka Idehara ◽  
...  
Keyword(s):  
Cell Division ◽  
Actin Polymerization ◽  
Time Lapse ◽  
Actin Dynamics ◽  
Filamentous Actin ◽  
Contractile Ring ◽  
Biological Phenomena ◽  
Underlying Mechanisms

Biological phenomena induced by terahertz (THz) irradiation are described in recent reports, but underlying mechanisms, structural and dynamical change of specific molecules are still unclear. In this paper, we performed time-lapse morphological analysis of human cells and found that THz irradiation halts cell division at cytokinesis. At the end of cytokinesis, the contractile ring, which consists of filamentous actin (F-actin), needs to disappear; however, it remained for 1 hour under THz irradiation. Induction of the functional structures of F-actin was also observed in interphase cells. Similar phenomena were also observed under chemical treatment (jasplakinolide), indicating that THz irradiation assists actin polymerization. We previously reported that THz irradiation enhances the polymerization of purified actin in vitro; our current work shows that it increases cytoplasmic F-actin in vivo. Thus, we identified one of the key biomechanisms affected by THz waves.

scholarly journals THz irradiation inhibits cell division by affecting actin dynamics

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0248381
Author(s):  
Shota Yamazaki ◽  
Yuya Ueno ◽  
Ryosuke Hosoki ◽  
Takanori Saito ◽  
Toshitaka Idehara ◽  
...  
Keyword(s):  
Cell Division ◽  
Actin Polymerization ◽  
Time Lapse ◽  
Actin Dynamics ◽  
Filamentous Actin ◽  
Contractile Ring ◽  
Biological Phenomena ◽  
Underlying Mechanisms

Biological phenomena induced by terahertz (THz) irradiation are described in recent reports, but underlying mechanisms, structural and dynamical change of specific molecules are still unclear. In this paper, we performed time-lapse morphological analysis of human cells and found that THz irradiation halts cell division at cytokinesis. At the end of cytokinesis, the contractile ring, which consists of filamentous actin (F-actin), needs to disappear; however, it remained for 1 hour under THz irradiation. Induction of the functional structures of F-actin was also observed in interphase cells. Similar phenomena were also observed under chemical treatment (jasplakinolide), indicating that THz irradiation assists actin polymerization. We previously reported that THz irradiation enhances the polymerization of purified actin in vitro; our current work shows that it increases cytoplasmic F-actin in vivo. Thus, we identified one of the key biomechanisms affected by THz waves.

scholarly journals αE-catenin regulates actin dynamics independently of cadherin-mediated cell–cell adhesion

2010 ◽  
Vol 189 (2) ◽  
pp. 339-352 ◽  
Author(s):  
Jacqueline M. Benjamin ◽  
Adam V. Kwiatkowski ◽  
Changsong Yang ◽  
Farida Korobova ◽  
Sabine Pokutta ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Actin Polymerization ◽  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Filamentous Actin ◽  
Vitro Binding ◽  
Adhesion Complex ◽  
E Cadherin ◽  
Cell Cell

αE-catenin binds the cell–cell adhesion complex of E-cadherin and β-catenin (β-cat) and regulates filamentous actin (F-actin) dynamics. In vitro, binding of αE-catenin to the E-cadherin–β-cat complex lowers αE-catenin affinity for F-actin, and αE-catenin alone can bind F-actin and inhibit Arp2/3 complex–mediated actin polymerization. In cells, to test whether αE-catenin regulates actin dynamics independently of the cadherin complex, the cytosolic αE-catenin pool was sequestered to mitochondria without affecting overall levels of αE-catenin or the cadherin–catenin complex. Sequestering cytosolic αE-catenin to mitochondria alters lamellipodia architecture and increases membrane dynamics and cell migration without affecting cell–cell adhesion. In contrast, sequestration of cytosolic αE-catenin to the plasma membrane reduces membrane dynamics. These results demonstrate that the cytosolic pool of αE-catenin regulates actin dynamics independently of cell–cell adhesion.

scholarly journals Regulation of anaphylactic responses by phosphatidylinositol phosphate kinase type I α

2005 ◽  
Vol 201 (6) ◽  
pp. 859-870 ◽  
Author(s):  
Junko Sasaki ◽  
Takehiko Sasaki ◽  
Masakazu Yamazaki ◽  
Kunie Matsuoka ◽  
Choji Taya ◽  
...  
Keyword(s):  
Mast Cells ◽  
Actin Polymerization ◽  
Negative Regulator ◽  
Type I ◽  
Filamentous Actin ◽  
Critical Signal ◽  
Cell Functions ◽  
Phosphatidylinositol Phosphate

The membrane phospholipid phosphatidylinositol 4, 5-bisphosphate [PI(4,5)P2] is a critical signal transducer in eukaryotic cells. However, the physiological roles of the type I phosphatidylinositol phosphate kinases (PIPKIs) that synthesize PI(4,5)P2 are largely unknown. Here, we show that the α isozyme of PIPKI (PIPKIα) negatively regulates mast cell functions and anaphylactic responses. In vitro, PIPKIα-deficient mast cells exhibited increased degranulation and cytokine production after Fcε receptor-I cross-linking. In vivo, PIPKIα−/− mice displayed enhanced passive cutaneous and systemic anaphylaxis. Filamentous actin was diminished in PIPKIα−/− mast cells, and enhanced degranulation observed in the absence of PIPKIα was also seen in wild-type mast cells treated with latrunculin, a pharmacological inhibitor of actin polymerization. Moreover, the association of FcεRI with lipid rafts and FcεRI-mediated activation of signaling proteins was augmented in PIPKIα−/− mast cells. Thus, PIPKIα is a negative regulator of FcεRI-mediated cellular responses and anaphylaxis, which functions by controlling the actin cytoskeleton and dynamics of FcεRI signaling. Our results indicate that the different PIPKI isoforms might be functionally specialized.

Small-Molecule Screen Identifies ROS as Key Regulators of Actin Dynamics in Neutrophils

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4641-4641
Author(s):  
Hidenori Hattori ◽  
Kulandayan K Subramanian ◽  
Hongbo R. Luo
Keyword(s):  
Small Molecule ◽  
Actin Polymerization ◽  
Neutrophil Migration ◽  
Physiological Role ◽  
Leading Edge ◽  
Actin Dynamics ◽  
Functional Screening ◽  
Cellular Processes

Abstract Precise spatial and temporal control of actin polymerization and depolymerization is essential for mediating various cellular processes such as migration, phagocytosis, vesicle trafficking and adhesion. In this study, we used a small-molecule functional screening approach to identify novel regulators of actin dynamics during neutrophil migration. Here we show that NADPH-oxidase dependent Reactive Oxygen Species act as negative regulators of actin polymerization. Neutrophils with pharmacologically inhibited oxidase or isolated from Chronic Granulomatous Disease (CGD) patient and mice displayed enhanced F-actin polymerization, multiple pseudopods formation and impaired chemotaxis. ROS localized to pseudopodia and inhibited actin polymerization by driving actin glutathionylation at the leading edge of migrating cells. Consistent with these in vitro results, adoptively transferred CGD murine neutrophils also showed impaired in vivo recruitment to sites of inflammation. Together, these results present a novel physiological role for ROS in regulation of action polymerization and shed new light on the pathogenesis of CGD.

N-WASP inhibitor wiskostatin nonselectively perturbs membrane transport by decreasing cellular ATP levels

2007 ◽  
Vol 292 (4) ◽  
pp. C1562-C1566 ◽  
Author(s):  
Christopher J. Guerriero ◽  
Ora A. Weisz
Keyword(s):  
Membrane Trafficking ◽  
Actin Polymerization ◽  
Cell Function ◽  
Actin Dynamics ◽  
Cellular Functions ◽  
Intact Cells ◽  
Atp Levels ◽  
Dependent Inhibition

Wiskott-Aldrich syndrome protein (WASP) and WAVE stimulate actin-related protein (Arp)2/3-mediated actin polymerization, leading to diverse downstream effects, including the formation and remodeling of cell surface protrusions, modulation of cell migration, and intracytoplasmic propulsion of organelles and pathogens. Selective inhibitors of individual Arp2/3 activators would enable more exact dissection of WASP- and WAVE-dependent cellular pathways and are potential therapeutic targets for viral pathogenesis. Wiskostatin is a recently described chemical inhibitor that selectively inhibits neuronal WASP (N-WASP)-mediated actin polymerization in vitro. A growing number of recent studies have utilized this drug in vivo to uncover novel cellular functions for N-WASP; however, the selectivity of wiskostatin in intact cells has not been carefully explored. In our studies with this drug, we observed rapid and dose-dependent inhibition of N-WASP-dependent membrane trafficking steps. Additionally, however, we found that addition of wiskostatin inhibited numerous other cellular functions that are not believed to be N-WASP dependent. Further studies revealed that wiskostatin treatment caused a rapid, profound, and irreversible decrease in cellular ATP levels, consistent with its global effects on cell function. Our data caution against the use of this drug as a selective perturbant of N-WASP-dependent actin dynamics in vivo.

scholarly journals Disease-associated missense mutations in the EVH1 domain disrupt intrinsic WASp function causing dysregulated actin dynamics and impaired dendritic cell migration

Blood ◽  
2013 ◽  
Vol 121 (1) ◽  
pp. 72-84 ◽  
Author(s):  
Austen J. J. Worth ◽  
Joao Metelo ◽  
Gerben Bouma ◽  
Dale Moulding ◽  
Marco Fritzsche ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Actin Dynamics ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Interacting Protein ◽  
Mutant Proteins ◽  
Dendritic Cell Migration ◽  
Biologic Function

Abstract Wiskott Aldrich syndrome (WAS), an X-linked immunodeficiency, results from loss-of-function mutations in the human hematopoietic cytoskeletal regulator gene WAS. Many missense mutations in the Ena Vasp homology1 (EVH1) domain preserve low-level WAS protein (WASp) expression and confer a milder clinical phenotype. Although disrupted binding to WASp-interacting protein (WIP) leads to enhanced WASp degradation in vivo, the intrinsic function of EVH1-mutated WASp is poorly understood. In the present study, we show that, despite mediating enhanced actin polymerization compared with wild-type WASp in vitro, EVH1 missense mutated proteins did not support full biologic function in cells, even when levels were restored by forced overexpression. Podosome assembly was aberrant and associated with dysregulated lamellipodia formation and impaired persistence of migration. At sites of residual podosome-associated actin polymerization, localization of EVH1-mutated proteins was preserved even after deletion of the entire domain, implying that WIP-WASp complex formation is not absolutely required for WASp localization. However, retention of mutant proteins in podosomes was significantly impaired and associated with reduced levels of WASp tyrosine phosphorylation. Our results indicate that the EVH1 domain is important not only for WASp stability, but also for intrinsic biologic activity in vivo.

scholarly journals Actin Dynamics Is Controlled by a Casein Kinase II and Phosphatase 2C Interplay on Toxoplasma gondii Toxofilin

2003 ◽  
Vol 14 (5) ◽  
pp. 1900-1912 ◽  
Author(s):  
Violaine Delorme ◽  
Xavier Cayla ◽  
Grazyna Faure ◽  
Alphonse Garcia ◽  
Isabelle Tardieux
Keyword(s):  
Toxoplasma Gondii ◽  
Actin Polymerization ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Gliding Motility ◽  
Actin Dynamics ◽  
Central Feature ◽  
Parasite Motility

Actin polymerization in Apicomplexa protozoa is central to parasite motility and host cell invasion. Toxofilin has been characterized as a protein that sequesters actin monomers and caps actin filaments in Toxoplasma gondii. Herein, we show that Toxofilin properties in vivo as in vitro depend on its phosphorylation. We identify a novel parasitic type 2C phosphatase that binds the Toxofilin/G-actin complex and a casein kinase II-like activity in the cytosol, both of which modulate the phosphorylation status of Toxofilin serine53. The interplay of these two molecules controls Toxofilin binding of G-actin as well as actin dynamics in vivo. Such functional interactions should play a major role in actin sequestration, a central feature of actin dynamics in Apicomplexa that underlies the spectacular speed and nature of parasite gliding motility.

scholarly journals Lack of correlation between changes in polyphosphoinositide levels and actin/gelsolin complexes in A431 cells treated with epidermal growth factor.

1991 ◽  
Vol 112 (6) ◽  
pp. 1151-1156 ◽  
Author(s):  
C Y Dadabay ◽  
E Patton ◽  
J A Cooper ◽  
L J Pike
Keyword(s):  
Growth Factor ◽  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Inositol Phosphates ◽  
A431 Cells ◽  
Pi Turnover ◽  
Epidermal Growth ◽  
Stimulation Of

The polyphosphoinositides, PIP and PIP2, have been proposed to regulate actin polymerization in vivo because they dissociate actin/gelsolin complexes in vitro. We tested this hypothesis by comparing the ability of EGF and bradykinin to affect PI metabolism and the actin cytoskeleton in A431 cells. EGF, but not bradykinin, was found to induce ruffling and dissociation of actin/gelsolin complexes in these cells. However, both EGF and bradykinin stimulated the accumulation of inositol phosphates in [3H]inositol-labeled cells indicating that stimulation of PI turnover is not sufficient for the induction of changes in actin/gelsolin complex levels. EGF stimulated a twofold increase in the level of PIP in A431 cells. Other phosphoinositide levels were not markedly altered. Treatment of the cells with cholera toxin abrogated the EGF-induced rise in PIP levels without altering the dissociation of actin from gelsolin. These data indicate that increases in PIP and/or PIP2 are not necessary for dissociation of actin/gelsolin complexes. Overall, these experiments suggest that in A431 cells, the effects of EGF on the actin cytoskeleton are unlikely to be mediated through changes in PIP or PIP2 levels.

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