scholarly journals Lamellipodin tunes cell migration by stabilizing protrusions and promoting adhesion formation

2019 ◽  
Author(s):  
Georgi Dimchev ◽  
Behnam Amiri ◽  
Ashley C. Humphries ◽  
Matthias Schaks ◽  
Vanessa Dimchev ◽  
...  
Keyword(s):  
Cell Migration ◽  
Actin Polymerization ◽  
Binding Protein ◽  
Critical Role ◽  
Adhesion Formation ◽  
Leading Edge ◽  
Actin Binding ◽  
Membrane Ruffling ◽  
Genetic Ablation ◽  
And Migration

ABSTRACTEfficient migration on adhesive surfaces involves the protrusion of lamellipodial actin networks and their subsequent stabilization by nascent adhesions. The actin binding protein lamellipodin (Lpd) is thought to play a critical role in lamellipodium protrusion, by delivering Ena/VASP proteins onto the growing plus ends of actin filaments and by interacting with the WAVE regulatory complex (WRC), an activator of the Arp2/3 complex, at the leading edge. Using B16-F1 melanoma cell lines, we demonstrate that genetic ablation of Lpd compromises protrusion efficiency and coincident cell migration without altering essential parameters of lamellipodia, including their maximal rate of forward advancement and actin polymerization. We also confirmed lamellipodia and migration phenotypes with CRISPR/Cas9-mediated Lpd knockout Rat2 fibroblasts, excluding cell type-specific effects. Moreover, computer-aided analysis of cell edge morphodynamics on B16-F1 cell lamellipodia revealed that loss of Lpd correlates with reduced temporal protrusion maintenance as a prerequisite of nascent adhesion formation. We conclude that Lpd optimizes protrusion and nascent adhesion formation by counteracting frequent, chaotic retraction and membrane ruffling.Summary statementWe describe how genetic ablation of the prominent actin- and VASP-binding protein lamellipodin combined with software-aided protrusion analysis uncovers mechanistic insights into its cellular function during cell migration.

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.

scholarly journals Local Myo9b RhoGAP activity regulates cell motility

2020 ◽  
pp. jbc.RA120.013623
Author(s):  
Sandra Angela Hemkemeyer ◽  
Veith Vollmer ◽  
Vera Schwarz ◽  
Birgit Lohmann ◽  
Ulrike Honnert ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Cell Morphology ◽  
Actin Polymerization ◽  
Rho Gtpase ◽  
Leading Edge ◽  
Cell Extension ◽  
Local Inhibition ◽  
And Migration ◽  
Directional Cell Migration

To migrate, cells assume a polarized morphology, extending forward with a leading edge with their trailing edge retracting back toward the cell body. Both cell extension and retraction critically depend on the organization and dynamics of the actin cytoskeleton, and the small, monomeric GTPases Rac and Rho are important regulators of actin. Activation of Rac induces actin polymerization and cell extension whereas activation of Rho enhances acto-myosin II contractility and cell retraction. To coordinate migration, these processes must be carefully regulated. The myosin Myo9b, a Rho GTPase activating protein (GAP), negatively regulates Rho activity and deletion of Myo9b in leukocytes impairs cell migration through increased Rho activity. However, it is not known whether cell motility is regulated by global or local inhibition of Rho activity by Myo9b. Here, we addressed this question by using Myo9b-deficient macrophage-like cells that expressed different recombinant Myo9b constructs. We found that Myo9b accumulates in lamellipodial extensions generated by Rac-induced actin polymerization as a function of its motor activity. Deletion of Myo9b in HL-60 derived macrophages altered cell morphology and impaired cell migration. Reintroduction of Myo9b or Myo9b motor and GAP mutants revealed that local GAP activity rescues cell morphology and migration. In summary, Rac activation leads to actin polymerization and recruitment of Myo9b, which locally inhibits Rho activity to enhance directional cell migration. In summary, Rac activation leads to actin polymerization and recruitment of Myo9b, which locally inhibits Rho activity to enhance directional cell migration.

Translocation of cortactin to the cell periphery is mediated by the small GTPase Rac1

1998 ◽  
Vol 111 (16) ◽  
pp. 2433-2443 ◽  
Author(s):  
S.A. Weed ◽  
Y. Du ◽  
J.T. Parsons
Keyword(s):  
Actin Polymerization ◽  
Intracellular Localization ◽  
Adhesion Formation ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Actin Binding ◽  
Cell Cortex ◽  
Cell Periphery ◽  
Membrane Ruffling

Small GTPases of the Rho family regulate signaling pathways that control actin cytoskeletal structures. In Swiss 3T3 cells, RhoA activation leads to stress fiber and focal adhesion formation, Rac1 to lamellipoda and membrane ruffles, and Cdc42 to microspikes and filopodia. Several downstream molecules mediating these effects have been recently identified. In this report we provide evidence that the intracellular localization of the actin binding protein cortactin, a Src kinase substrate, is regulated by the activation of Rac1. Cortactin redistributes from the cytoplasm into membrane ruffles as a result of growth factor-induced Rac1 activation, and this translocation is blocked by expression of dominant negative Rac1N17. Expression of constitutively active Rac1L61 evoked the translocation of cortactin from cytoplasmic pools into peripheral membrane ruffles. Expression of mutant forms of the serine/threonine kinase PAK1, a downstream effector of Rac1 and Cdc42 recently demonstrated to trigger cortical actin polymerization and membrane ruffling, also led to the translocation of cortactin to the cell cortex, although this was effectively blocked by coexpression of Rac1N17. Collectively these data provide evidence for cortactin as a putative target of Rac1-induced signal transduction events involved in membrane ruffling and lamellipodia formation.

scholarly journals Regulation of cell migration and survival by focal adhesion targeting of Lasp-1

2004 ◽  
Vol 165 (3) ◽  
pp. 421-432 ◽  
Author(s):  
Yi Hsing Lin ◽  
Zee-Yong Park ◽  
Dayin Lin ◽  
Anar A. Brahmbhatt ◽  
Marie-Christine Rio ◽  
...  
Keyword(s):  
Cell Migration ◽  
Growth Factors ◽  
Focal Adhesion ◽  
Large Scale ◽  
Actin Polymerization ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Actin Binding ◽  
Cell Periphery ◽  
Ecm Proteins

Large-scale proteomic and functional analysis of isolated pseudopodia revealed the Lim, actin, and SH3 domain protein (Lasp-1) as a novel protein necessary for cell migration, but not adhesion to, the extracellular matrix (ECM). Lasp-1 is a ubiquitously expressed actin-binding protein with a unique domain configuration containing SH3 and LIM domains, and is overexpressed in 8–12% of human breast cancers. We find that stimulation of nonmotile and quiescent cells with growth factors or ECM proteins facilitates Lasp-1 relocalization from the cell periphery to the leading edge of the pseudopodium, where it associates with nascent focal complexes and areas of actin polymerization. Interestingly, although Lasp-1 dynamics in migratory cells occur independently of c-Abl kinase activity and tyrosine phosphorylation, c-Abl activation by apoptotic agents specifically promotes phosphorylation of Lasp-1 at tyrosine 171, which is associated with the loss of Lasp-1 localization to focal adhesions and induction of cell death. Thus, Lasp-1 is a dynamic focal adhesion protein necessary for cell migration and survival in response to growth factors and ECM proteins.

scholarly journals Actin-binding protein promotes the bipolar and perpendicular branching of actin filaments.

1980 ◽  
Vol 87 (3) ◽  
pp. 841-848 ◽  
Author(s):  
J H Hartwig ◽  
J Tyler ◽  
T P Stossel
Keyword(s):  
Actin Filaments ◽  
Actin Polymerization ◽  
Average Length ◽  
Binding Protein ◽  
Actin Binding ◽  
Branch Points ◽  
Heavy Meromyosin ◽  
Actin Binding Protein ◽  
Protein Dimers ◽  
Protein Molecules

Branching filaments with striking perpendicularity form when actin polymerizes in the presence of macrophage actin-binding protein. Actin-binding protein molecules are visible at the branch points. Compared with actin polymerized in the absence of actin-binding proteins, not only do the filaments branch but the average length of the actin filaments decreases from 3.2 to 0.63 micrometer. Arrowhead complexes formed by addition of heavy meromyosin molecules to the branching actin filaments point toward the branch points. Actin-binding protein also accelerates the onset of actin polymerization. All of these findings show that actin filaments assemble from nucleating sites on actin-binding protein dimers. A branching polymerization of actin filaments from a preexisting lattice of actin filaments joined by actin-binding protein molecules could generate expansion of cortical cytoplasm in amoeboid cells.

Distinct signals via Rho GTPases and Src drive shape changes by thrombin and sphingosine-1-phosphate in endothelial cells

2002 ◽  
Vol 115 (12) ◽  
pp. 2475-2484 ◽  
Author(s):  
Valérie Vouret-Craviari ◽  
Christine Bourcier ◽  
Etienne Boulter ◽  
Ellen Van Obberghen-Schilling
Keyword(s):  
Endothelial Cells ◽  
Rho Gtpases ◽  
Actin Polymerization ◽  
Morphological Changes ◽  
Umbilical Vein ◽  
Cell Spreading ◽  
Actin Binding ◽  
Sphingosine 1 Phosphate ◽  
And Migration ◽  
Umbilical Vein Endothelial Cells

Soluble mediators such as thrombin and sphingosine-1-phosphate regulate morphological changes in endothelial cells that affect vascular permeability and new blood vessel formation. Although these ligands activate a similar set of heterotrimeric G proteins, thrombin causes cell contraction and rounding whereas sphingosine-1-phosphate induces cell spreading and migration. A functional requirement for Rho family GTPases in the cytoskeletal responses to both ligands has been established, yet the dynamics of their regulation and additional signaling mechanisms that lead to such opposite effects remain poorly understood. Using a pull-down assay to monitor the activity of Rho GTPases in human umbilical vein endothelial cells, we find significant temporal and quantitative differences in RhoA and Rac1 activation. High levels of active RhoA rapidly accumulate in cells in response to thrombin whereas Rac1 is inhibited. In contrast, sphingosine-1-phosphate addition leads to comparatively weak and delayed activation of RhoA and it activates Rac1. In addition, we show here that sphingosine-1-phosphate treatment activates a Src family kinase and triggers recruitment of the F-actin-binding protein cortactin to sites of actin polymerization at the rim of membrane ruffles. Both Src and Rac pathways are essential for lamellipodia targeting of cortactin. Further, Src plays a determinant role in sphingosine-1-phosphate-induced cell spreading and migration. Taken together these data demonstrate that the thrombin-induced contractile and immobile phenotype in endothelial cells reflects both robust RhoA activation and Rac inhibition, whereas Src- and Rac-dependent events couple sphingosine-1-phosphate receptors to the actin polymerizing machinery that drives the extension of lamellipodia and cell migration.

Abstract 958: Cardiac MyBP-C Modulates Actomyosin Interactions: Evidence From Cardiac MyBP-c−/ − Mice

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Yves Lecarpentier ◽  
Nicolas Vignier ◽  
Patricia Oliviero ◽  
Miguel Cortes-Morichetti ◽  
Lucie Carrier ◽  
...  
Keyword(s):  
Thin Filament ◽  
Isometric Force ◽  
Binding Protein ◽  
Critical Role ◽  
Cardiac Contractility ◽  
Left Ventricular ◽  
Actin Binding ◽  
Power Stroke ◽  
Shortening Velocity

The precise role of cardiac myosin binding protein C (cMyBP-C) on actomyosin interaction (AMI) remains unknown. We hypothesized that the lack of cMyBP-C impaired cardiac AMI. Experiments were performed on 16 weeks old cMyBP-C −/− (KO) and age-matched wild-type (WT) mice (n=20/group). In vitro mechanical and energetics properties were performed on left ventricular (LV) papillary muscles and Huxley’s equations were used to characterize AMI. In vitro motility assays were performed using myosin purified from LV. Myosin-based sliding velocities of actin filaments were analyzed at baseline, after pretreatment of the myosin solution with 10 umol of the catalytic subunit of PKA and/or in the presence of increasing amount of α-actinin, an actin-binding protein that acts as an internal load thereby providing an index of relative isometric force. Western-blot analysis was used to quantify cMyBP-C and phosphorylated cMyBP-C in myosin solutions. Compared to WT, both total tension and maximum shortening velocity were lower in KO (p<0.001). The probability for myosin to be weakly bound to actin was higher in KO than in WT (8.6±0.3 vs. 5.4±0.2%, p<0.05), whereas the number of strongly bound, high-force generated state cross-bridges was lower in KO (6.4±0.9 vs. 11.6±1.0 10 9 /mm 2 , p<0.001). The unitary force per AMI was lower in KO than in WT (p<0.01). At baseline, myosin-based velocities of actin were slower in KO than in WT (1.65±0.01 vs. 1.98±0.01 um/s, p<0.01). The minimum amount of α-actinin needed to completely arrest the thin filament motility was significantly higher in WT than in KO (73.3±1.1 vs 29.1±0.1 ug/l, p<0.001). As expected, cMyBP-C was present in WT myosin solution whereas cMyBP-C was not detected in KO. In WT, PKA induced a 1.6-fold increased in cMyBP-C phosphorylation (p<0.01) associated with a 53±1% increase in the amount of α-actinin required to arrest thin filament motility (p<0.001). PKA did not modify sliding velocity in WT. In KO, PKA had no effect on myosin sliding. We conclude that cMyBP-C regulates AMI by limiting inefficient cross-bridge formation and by enhancing the power stroke step. Phosphorylation status of cMyBP-C appears to play a critical role on cardiac contractility through a direct effect on the myosin molecular motor.

scholarly journals Actin-binding Protein Drebrin Regulates HIV-1-triggered Actin Polymerization and Viral Infection

2013 ◽  
Vol 288 (39) ◽  
pp. 28382-28397 ◽  
Author(s):  
Mónica Gordón-Alonso ◽  
Vera Rocha-Perugini ◽  
Susana Álvarez ◽  
Ángeles Ursa ◽  
Nuria Izquierdo-Useros ◽  
...  
Keyword(s):  
Viral Infection ◽  
Actin Polymerization ◽  
Binding Protein ◽  
Actin Binding ◽  
Actin Binding Protein ◽  
Hiv 1

scholarly journals CaM kinase IIδ2-dependent regulation of vascular smooth muscle cell polarization and migration

2008 ◽  
Vol 294 (6) ◽  
pp. C1465-C1475 ◽  
Author(s):  
Melissa Z. Mercure ◽  
Roman Ginnan ◽  
Harold A. Singer
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Vascular Smooth Muscle ◽  
Cell Monolayer ◽  
Leading Edge ◽  
Cell Polarization ◽  
Loss Of Function ◽  
Downstream Signaling ◽  
Transient Activation ◽  
And Migration

Previous studies indicate involvement of the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) in vascular smooth muscle (VSM) cell migration. In the present study, molecular loss-of-function studies were used specifically to assess the role of the predominant CaMKIIδ2 isoform on VSM cell migration using a scratch wound healing assay. Targeted CaMKIIδ2 knockdown using siRNA or inhibition of activity by overexpressing a kinase-negative mutant resulted in attenuation of VSM cell migration. Temporal and spatial assessments of kinase autophosphorylation indicated rapid and transient activation in response to wounding, in addition to a sustained activation in the leading edge of migrating and spreading cells. Furthermore, siRNA-mediated suppression of CaMKIIδ2 resulted in the inhibition of wound-induced Rac activation and Golgi reorganization, and disruption of leading edge morphology, indicating an important function for CaMKIIδ2 in regulating VSM cell polarization. Numerous previous reports link activation of CaMKII to ERK1/2 signaling in VSM. Wound-induced ERK1/2 activation was also found to be dependent on CaMKII; however, ERK activity did not account for effects of CaMKII in regulating Golgi polarization, indicating alternative mechanisms by which CaMKII affects the complex events involved in cell migration. Wounding a VSM cell monolayer results in CaMKIIδ2 activation, which positively regulates VSM cell polarization and downstream signaling, including Rac and ERK1/2 activation, leading to cell migration.

Proteomic profiling reveals that EhPC4 transcription factor induces cell migration through up-regulation of the 16-kDa actin-binding protein EhABP16 in Entamoeba histolytica

2014 ◽  
Vol 111 ◽  
pp. 46-58 ◽  
Author(s):  
Olga Hernández de la Cruz ◽  
Marcos Muñiz-Lino ◽  
Nancy Guillén ◽  
Christian Weber ◽  
Laurence A. Marchat ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Migration ◽  
Entamoeba Histolytica ◽  
Binding Protein ◽  
Actin Binding ◽  
Proteomic Profiling ◽  
Actin Binding Protein
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