scholarly journals The SCAR/WAVE complex is necessary for proper regulation of traction stresses during amoeboid motility

2011 ◽  
Vol 22 (21) ◽  
pp. 3995-4003 ◽  
Author(s):  
Effie Bastounis ◽  
Ruedi Meili ◽  
Baldomero Alonso-Latorre ◽  
Juan C. del Álamo ◽  
Juan C. Lasheras ◽  
...  
Keyword(s):  
Cell Migration ◽  
Actin Polymerization ◽  
Leading Edge ◽  
Wild Type ◽  
Amoeboid Motility ◽  
Elastic Substrates ◽  
Random Manner ◽  
Motility Cycle ◽  
Wave Complex

Cell migration requires a tightly regulated, spatiotemporal coordination of underlying biochemical pathways. Crucial to cell migration is SCAR/WAVE–mediated dendritic F-actin polymerization at the cell's leading edge. Our goal is to understand the role the SCAR/WAVE complex plays in the mechanics of amoeboid migration. To this aim, we measured and compared the traction stresses exerted by Dictyostelium cells lacking the SCAR/WAVE complex proteins PIR121 (pirA−) and SCAR (scrA−) with those of wild-type cells while they were migrating on flat, elastic substrates. We found that, compared to wild type, both mutant strains exert traction stresses of different strengths that correlate with their F-actin levels. In agreement with previous studies, we found that wild-type cells migrate by repeating a motility cycle in which the cell length and strain energy exerted by the cells on their substrate vary periodically. Our analysis also revealed that scrA− cells display an altered motility cycle with a longer period and a lower migration velocity, whereas pirA− cells migrate in a random manner without implementing a periodic cycle. We present detailed characterization of the traction-stress phenotypes of the various cell lines, providing new insights into the role of F-actin polymerization in regulating cell–substratum interactions and stresses required for motility.

scholarly journals CYFIP2 containing WAVE complexes inhibit cell migration

2020 ◽  
Author(s):  
Anna Polesskaya ◽  
Arthur Boutillon ◽  
Yanan Wang ◽  
Marc Lavielle ◽  
Sophie Vacher ◽  
...  
Keyword(s):  
Cell Migration ◽  
Mammary Epithelial Cells ◽  
Leading Edge ◽  
Good Prognosis ◽  
Mammary Epithelial ◽  
Breast Cancer Patients ◽  
Loss Of Function ◽  
A Cell ◽  
Wave Complex

ABSTRACTBranched actin networks polymerized by the Arp2/3 complex are critical for cell migration. The WAVE complex is the major Arp2/3 activator at the leading edge of migrating cells. However, multiple distinct WAVE complexes can be assembled in a cell, due to the combinatorial complexity of paralogous subunits. When systematically analyzing the contribution of each WAVE complex subunit to the metastasis-free survival of breast cancer patients, we found that overexpression of the CYFIP2 subunit was surprisingly associated with good prognosis. Gain and loss of function experiments in transformed and untransformed mammary epithelial cells revealed that cell migration was always inversely related to CYFIP2 levels. The role of CYFIP2 was systematically opposite to the role of the paralogous subunit CYFIP1 or of the NCKAP1 subunit. The specific CYFIP2 function in inhibiting cell migration was related to its unique ability to down-regulate classical pro-migratory WAVE complexes. The anti-migratory function of CYFIP2 was also revealed in migration of prechordal plate cells during gastrulation of the zebrafish embryo, indicating that the unique function of CYFIP2 is critically important in both physiological and pathophysiological migrations.

scholarly journals Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
Begoña Álvarez-González ◽  
Effie Bastounis ◽  
Ruedi Meili ◽  
Juan C. del Álamo ◽  
Richard Firtel ◽  
...  
Keyword(s):  
Cell Migration ◽  
Traction Force ◽  
Leading Edge ◽  
Cell Types ◽  
Traction Forces ◽  
Amoeboid Cell ◽  
Periodic Movement ◽  
Wide Range ◽  
Motility Cycle ◽  
Wave Complex

Migrating cells exert traction forces when moving. Amoeboid cell migration is a common type of cell migration that appears in many physiological and pathological processes and is performed by a wide variety of cell types. Understanding the coupling of the biochemistry and mechanics underlying the process of migration has the potential to guide the development of pharmacological treatment or genetic manipulations to treat a wide range of diseases. The measurement of the spatiotemporal evolution of the traction forces that produce the movement is an important aspect for the characterization of the locomotion mechanics. There are several methods to calculate the traction forces exerted by the cells. Currently the most commonly used ones are traction force microscopy methods based on the measurement of the deformation induced by the cells on elastic substrate on which they are moving. Amoeboid cells migrate by implementing a motility cycle based on the sequential repetition of four phases. In this paper, we review the role that specific cytoskeletal components play in the regulation of the cell migration mechanics. We investigate the role of specific cytoskeletal components regarding the ability of the cells to perform the motility cycle effectively and the generation of traction forces. The actin nucleation in the leading edge of the cell, carried by the ARP2/3 complex activated through the SCAR/WAVE complex, has shown to be fundamental to the execution of the cyclic movement and to the generation of the traction forces. The protein PIR121, a member of the SCAR/WAVE complex, is essential to the proper regulation of the periodic movement and the protein SCAR, also included in the SCAR/WAVE complex, is necessary for the generation of the traction forces during migration. The protein Myosin II, an important F-actin cross-linker and motor protein, is essential to cytoskeletal contractility and to the generation and proper organization of the traction forces during migration.

scholarly journals Akt isoforms differentially regulate neutrophil functions

Blood ◽  
2010 ◽  
Vol 115 (21) ◽  
pp. 4237-4246 ◽  
Author(s):  
Jia Chen ◽  
Haiyang Tang ◽  
Nissim Hay ◽  
Jingsong Xu ◽  
Richard D. Ye
Keyword(s):  
Kinase Inhibitor ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Leading Edge ◽  
Neutrophil Activation ◽  
Enzyme Release ◽  
Wild Type ◽  
Akt Isoforms ◽  
Phosphoinositide 3 Kinase ◽  
O2 Production

In neutrophils, the phosphoinositide 3-kinase/Akt signaling cascade is involved in migration, degranulation, and O2− production. However, it is unclear whether the Akt kinase isoforms have distinct functions in neutrophil activation. Here we report functional differences between the 2 major Akt isoforms in neutrophil activation on the basis of studies in which we used individual Akt1 and Akt2 knockout mice. Akt2−/− neutrophils exhibited decreased cell migration, granule enzyme release, and O2− production compared with wild-type and Akt1−/− neutrophils. Surprisingly, Akt2 deficiency and pharmacologic inhibition of Akt also abrogated phorbol ester-induced O2− production, which was unaffected by treatment with the phosphoinositide 3-kinase inhibitor LY294002. The decreased O2− production in Akt2−/− neutrophils was accompanied by reduced p47phox phosphorylation and its membrane translocation, suggesting that Akt2 is important for the assembly of phagocyte nicotinamide adenine dinucleotide phosphate oxidase. In wild-type neutrophils, Akt2 but not Akt1 translocated to plasma membrane upon chemoattractant stimulation and to the leading edge in polarized neutrophils. In the absence of Akt2, chemoattractant-induced Akt protein phosphorylation was significantly reduced. These results demonstrate a predominant role of Akt2 in regulating neutrophil functions and provide evidence for differential activation of the 2 Akt isoforms in neutrophils.

scholarly journals Contribution of Filopodia to Cell Migration: A Mechanical Link between Protrusion and Contraction

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Fei Xue ◽  
Deanna M. Janzen ◽  
David A. Knecht
Keyword(s):  
Cell Migration ◽  
Actin Polymerization ◽  
Myosin Ii ◽  
Temporal Distribution ◽  
Leading Edge ◽  
Distal Portion ◽  
Actin Binding ◽  
Actin Networks ◽  
Motile Cells ◽  
A Cell

Numerous F-actin containing structures are involved in regulating protrusion of membrane at the leading edge of motile cells. We have investigated the structure and dynamics of filopodia as they relate to events at the leading edge and the function of the trailing actin networks. We have found that although filopodia contain parallel bundles of actin, they contain a surprisingly nonuniform spatial and temporal distribution of actin binding proteins. Along the length of the actin filaments in a single filopodium, the most distal portion contains primarily T-plastin, while the proximal portion is primarily bound byα-actinin and coronin. Some filopodia are stationary, but lateral filopodia move with respect to the leading edge. They appear to form a mechanical link between the actin polymerization network at the front of the cell and the myosin motor activity in the cell body. The direction of lateral filopodial movement is associated with the direction of cell migration. When lateral filopodia initiate from and move toward only one side of a cell, the cell will turn opposite to the direction of filopodial flow. Therefore, this filopodia-myosin II system allows actin polymerization driven protrusion forces and myosin II mediated contractile force to be mechanically coordinated.

Chlamydia pneumoniae infection induces vascular smooth muscle cell migration via Rac1 activation

2014 ◽  
Vol 63 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Junxia Zhang ◽  
Haiwei Wang ◽  
Lijun Zhang ◽  
Tengteng Zhang ◽  
Beibei Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Botulinum Toxin ◽  
Vascular Smooth Muscle ◽  
Chlamydia Pneumoniae ◽  
Leading Edge ◽  
Primary Role ◽  
Phosphatidylinositol 3 Kinase ◽  
Smooth Muscle Cell Migration

Chlamydia pneumoniae infection has been shown to be associated with the development of atherosclerosis by promoting the migration of vascular smooth muscle cells (VSMCs). However, how C. pneumoniae infection induces VSMC migration is not fully understood. A primary role of Ras-related C3 botulinum toxin substrate 1 (Rac1) is to generate a protrusive force at the leading edge that contributes to cell migration. Whether Rac1 activation plays a role in C. pneumoniae infection-induced VSMC migration is not well defined. In the present study, we therefore examined Rac1 activation in C. pneumoniae-infected rat primary VSMCs and the role of Rac1 activation in C. pneumoniae infection-induced VSMC migration. Glutathione S-transferase pull-down assay results showed that Rac1 was activated in C. pneumoniae-infected rat primary VSMCs. A Rac1 inhibitor, NSC23766 (50 µM,) suppressed Rac1 activation stimulated by C. pneumoniae infection, and thereby inhibited C. pneumoniae infection-induced VSMC migration. In addition, C. pneumoniae infection-induced Rac1 activation in the VSMCs was blocked by LY294002 (25 µM), an inhibitor of phosphatidylinositol 3-kinase (PI3K). Taken together, these data suggest that C. pneumoniae infection promotes VSMC migration, possibly through activating Rac1 via PI3K.

scholarly journals Role of c-Abl tyrosine kinase in smooth muscle cell migration

2014 ◽  
Vol 306 (8) ◽  
pp. C753-C761 ◽  
Author(s):  
Rachel A. Cleary ◽  
Ruping Wang ◽  
Omar Waqar ◽  
Harold A. Singer ◽  
Dale D. Tang
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Cell Adhesion ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Leading Edge ◽  
Actin Dynamics ◽  
Cell Edge ◽  
Smooth Muscle Cell Migration

c-Abl is a nonreceptor protein tyrosine kinase that has a role in regulating smooth muscle cell proliferation and contraction. The role of c-Abl in smooth muscle cell migration has not been investigated. In the present study, c-Abl was found in the leading edge of smooth muscle cells. Knockdown of c-Abl by RNA interference attenuated smooth muscle cell motility as evidenced by time-lapse microscopy. Furthermore, the actin-associated proteins cortactin and profilin-1 (Pfn-1) have been implicated in cell migration. In this study, cell adhesion induced cortactin phosphorylation at Tyr-421, an indication of cortactin activation. Phospho-cortactin and Pfn-1 were also found in the cell edge. Pfn-1 directly interacted with cortactin in vitro. Silencing of c-Abl attenuated adhesion-induced cortactin phosphorylation and Pfn-1 localization in the cell edge. To assess the role of cortactin/Pfn-1 coupling, we developed a cell-permeable peptide. Treatment with the peptide inhibited the interaction of cortactin with Pfn-1 without affecting cortactin phosphorylation. Moreover, treatment with the peptide impaired the recruitment of Pfn-1 to the leading edge and cell migration. Finally, β1-integrin was required for the recruitment of c-Abl to the cell edge. Inhibition of actin dynamics impaired the spatial distribution of c-Abl. These results suggest that β1-integrin may recruit c-Abl to the leading cell edge, which may regulate cortactin phosphorylation in response to cell adhesion. Phosphorylated cortactin may facilitate the recruitment of Pfn-1 to the cell edge, which promotes localized actin polymerization, leading edge formation, and cell movement. Conversely, actin dynamics may strengthen the recruitment of c-Abl to the leading edge.

scholarly journals The N-Terminus ofDictyosteliumScar Interacts with Abi and HSPC300 and Is Essential for Proper Regulation and Function

2007 ◽  
Vol 18 (5) ◽  
pp. 1609-1620 ◽  
Author(s):  
Diana Caracino ◽  
Cheryl Jones ◽  
Mark Compton ◽  
Charles L. Saxe
Keyword(s):  
Actin Polymerization ◽  
Terminal Region ◽  
Wild Type ◽  
Large Molecular Weight ◽  
Weight Protein ◽  
And Function ◽  
Necessary And Sufficient

Scar/WAVE proteins, members of the conserved Wiskott-Aldrich syndrome (WAS) family, promote actin polymerization by activating the Arp2/3 complex. A number of proteins, including a complex containing Nap1, PIR121, Abi1/2, and HSPC300, interact with Scar/WAVE, though the role of this complex in regulating Scar function remains unclear. Here we identify a short N-terminal region of Dictyostelium Scar that is necessary and sufficient for interaction with HSPC300 and Abi in vitro. Cells expressing Scar lacking this N-terminal region show abnormalities in F-actin distribution, cell morphology, movement, and cytokinesis. This is true even in the presence of wild-type Scar. The data suggest that the first 96 amino acids of Scar are necessary for participation in a large-molecular-weight protein complex, and that this Scar-containing complex is responsible for the proper localization and regulation of Scar. The presence of mis-regulated or unregulated Scar has significant deleterious effects on cells and may explain the need to keep Scar activity tightly controlled in vivo either by assembly in a complex or by rapid degradation.

scholarly journals Essential and nonredundant roles for Diaphanous formins in cortical microtubule capture and directed cell migration

2014 ◽  
Vol 25 (5) ◽  
pp. 658-668 ◽  
Author(s):  
Pascale Daou ◽  
Salma Hasan ◽  
Dennis Breitsprecher ◽  
Emilie Baudelet ◽  
Luc Camoin ◽  
...  
Keyword(s):  
Cell Migration ◽  
Actin Polymerization ◽  
Affinity Purification ◽  
Cortical Microtubule ◽  
Leading Edge ◽  
Large Family ◽  
Mass Spectrometry Analysis ◽  
Cell Cortex ◽  
Spectrometry Analysis ◽  
Microtubule Capture

Formins constitute a large family of proteins that regulate the dynamics and organization of both the actin and microtubule cytoskeletons. Previously we showed that the formin mDia1 helps tether microtubules at the cell cortex, acting downstream of the ErbB2 receptor tyrosine kinase. Here we further study the contributions of mDia1 and its two most closely related formins, mDia2 and mDia3, to cortical microtubule capture and ErbB2-dependent breast carcinoma cell migration. We find that depletion of each of these three formins strongly disrupts chemotaxis without significantly affecting actin-based structures. Further, all three formins are required for formation of cortical microtubules in a nonredundant manner, and formin proteins defective in actin polymerization remain active for microtubule capture. Using affinity purification and mass spectrometry analysis, we identify differential binding partners of the formin-homology domain 2 (FH2) of mDia1, mDia2, and mDia3, which may explain their nonredundant roles in microtubule capture. The FH2 domain of mDia1 specifically interacts with Rab6-interacting protein 2 (Rab6IP2). Further, mDia1 is required for cortical localization of Rab6IP2, and concomitant depletion of Rab6IP2 and IQGAP1 severely disrupts cortical capture of microtubules, demonstrating the coinvolvement of mDia1, IQGAP1, and Rab6IP2 in microtubule tethering at the leading edge.

scholarly journals Actin-dependent Lamellipodia Formation and Microtubule-dependent Tail Retraction Control-directed Cell Migration

2000 ◽  
Vol 11 (9) ◽  
pp. 2999-3012 ◽  
Author(s):  
Christoph Ballestrem ◽  
Bernhard Wehrle-Haller ◽  
Boris Hinz ◽  
Beat A. Imhof
Keyword(s):  
Cell Migration ◽  
Cell Body ◽  
Actin Polymerization ◽  
Green Fluorescence Protein ◽  
Time Lapse ◽  
Dependent Manner ◽  
Directed Cell Migration ◽  
Cell Front ◽  
Fluorescence Protein

Migrating cells are polarized with a protrusive lamella at the cell front followed by the main cell body and a retractable tail at the rear of the cell. The lamella terminates in ruffling lamellipodia that face the direction of migration. Although the role of actin in the formation of lamellipodia is well established, it remains unclear to what degree microtubules contribute to this process. Herein, we have studied the contribution of microtubules to cell motility by time-lapse video microscopy on green flourescence protein-actin- and tubulin-green fluorescence protein–transfected melanoma cells. Treatment of cells with either the microtubule-disrupting agent nocodazole or with the stabilizing agent taxol showed decreased ruffling and lamellipodium formation. However, this was not due to an intrinsic inability to form ruffles and lamellipodia because both were restored by stimulation of cells with phorbol 12-myristate 13-acetate in a Rac-dependent manner, and by stem cell factor in melanoblasts expressing the receptor tyrosine kinase c-kit. Although ruffling and lamellipodia were formed without microtubules, the microtubular network was needed for advancement of the cell body and the subsequent retraction of the tail. In conclusion, we demonstrate that the formation of lamellipodia can occur via actin polymerization independently of microtubules, but that microtubules are required for cell migration, tail retraction, and modulation of cell adhesion.

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