mRNA encoding WAVE–Arp2/3-associated proteins is co-localized with foci of active protein synthesis at the leading edge of MRC5 fibroblasts during cell migration

2013 ◽  
Vol 452 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Mark Willett ◽  
Michele Brocard ◽  
Hilary J. Pollard ◽  
Simon J. Morley
Keyword(s):  
Protein Synthesis ◽  
Mammalian Cells ◽  
Structural Characteristics ◽  
Leading Edge ◽  
Cell Spreading ◽  
Active Protein ◽  
Associated Proteins ◽  
Steady State Levels ◽  
And Migration ◽  
Syndrome Protein

During cell spreading, mammalian cells migrate using lamellipodia formed from a large dense branched actin network which produces the protrusive force required for leading edge advancement. The formation of lamellipodia is a dynamic process and is dependent on a variety of protein cofactors that mediate their local regulation, structural characteristics and dynamics. In the present study, we show that mRNAs encoding some structural and regulatory components of the WAVE [WASP (Wiskott–Aldrich syndrome protein) verprolin homologous] complex are localized to the leading edge of the cell and associated with sites of active translation. Furthermore, we demonstrate that steady-state levels of ArpC2 and Rac1 proteins increase at the leading edge during cell spreading, suggesting that localized protein synthesis has a pivotal role in controlling cell spreading and migration.

scholarly journals The endocytic protein GRAF1 is directed to cell-matrix adhesion sites and regulates cell spreading

2011 ◽  
Vol 22 (22) ◽  
pp. 4380-4389 ◽  
Author(s):  
Gary J. Doherty ◽  
Monika K. Åhlund ◽  
Mark T. Howes ◽  
Björn Morén ◽  
Robert G. Parton ◽  
...  
Keyword(s):  
Rho Gtpase ◽  
Morphological Changes ◽  
Leading Edge ◽  
Cell Spreading ◽  
Endocytic Pathway ◽  
Membrane Microdomains ◽  
Membrane Turnover ◽  
Cell Matrix ◽  
Adhesion Sites ◽  
And Migration

The rho GTPase-activating protein GTPase regulator associated with focal adhesion kinase-1 (GRAF1) remodels membranes into tubulovesicular clathrin-independent carriers (CLICs) mediating lipid-anchored receptor endocytosis. However, the cell biological functions of this highly prevalent endocytic pathway are unclear. In this article, we present biochemical and cell biological evidence that GRAF1 interacted with a network of endocytic and adhesion proteins and was found enriched at podosome-like adhesions and src-induced podosomes. We further demonstrate that these sites comprise microdomains of highly ordered lipid enriched in GRAF1 endocytic cargo. GRAF1 activity was upregulated in spreading cells and uptake via CLICs was concentrated at the leading edge of migrating cells. Depletion of GRAF1, which inhibits CLIC generation, resulted in profound defects in cell spreading and migration. We propose that GRAF1 remodels membrane microdomains at adhesion sites into endocytic carriers, facilitating membrane turnover during cell morphological changes.

scholarly journals Tiam1 interaction with the PAR complex promotes talin-mediated Rac1 activation during polarized cell migration

2012 ◽  
Vol 199 (2) ◽  
pp. 331-345 ◽  
Author(s):  
Shujie Wang ◽  
Takashi Watanabe ◽  
Kenji Matsuzawa ◽  
Akira Katsumi ◽  
Mai Kakeno ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Cell Migration ◽  
Protein Kinase ◽  
Leading Edge ◽  
Cell Spreading ◽  
Kinase C ◽  
Rac1 Activity ◽  
Directional Movement ◽  
And Migration ◽  
Migrating Cells

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration.

scholarly journals Trafficking defects in WASH-knockout fibroblasts originate from collapsed endosomal and lysosomal networks

2012 ◽  
Vol 23 (16) ◽  
pp. 3215-3228 ◽  
Author(s):  
Timothy S. Gomez ◽  
Jacquelyn A. Gorman ◽  
Amaia Artal-Martinez de Narvajas ◽  
Alexander O. Koenig ◽  
Daniel D. Billadeau
Keyword(s):  
Mammalian Cells ◽  
Cellular Localization ◽  
Growth Factor Receptor ◽  
Membrane Domains ◽  
Filamentous Actin ◽  
Endosomal Sorting ◽  
Associated Proteins ◽  
Epidermal Growth ◽  
Trafficking Defects ◽  
Syndrome Protein

The Arp2/3-activator Wiskott–Aldrich syndrome protein and Scar homologue (WASH) is suggested to regulate actin-dependent membrane scission during endosomal sorting, but its cellular roles have not been fully elucidated. To investigate WASH function, we generated tamoxifen-inducible WASH-knockout mouse embryonic fibroblasts (WASHout MEFs). Of interest, although EEA1+ endosomes were enlarged, collapsed, and devoid of filamentous-actin and Arp2/3 in WASHout MEFs, we did not observe elongated membrane tubules emanating from these disorganized endomembranes. However, collapsed WASHout endosomes harbored segregated subdomains, containing either retromer cargo recognition complex–associated proteins or EEA1. In addition, we observed global collapse of LAMP1+ lysosomes, with some lysosomal membrane domains associated with endosomes. Both epidermal growth factor receptor (EGFR) and transferrin receptor (TfnR) exhibited changes in steady-state cellular localization. EGFR was directed to the lysosomal compartment and exhibited reduced basal levels in WASHout MEFs. However, although TfnR was accumulated with collapsed endosomes, it recycled normally. Moreover, EGF stimulation led to efficient EGFR degradation within enlarged lysosomal structures. These results are consistent with the idea that discrete receptors differentially traffic via WASH-dependent and WASH-independent mechanisms and demonstrate that WASH-mediated F-actin is requisite for the integrity of both endosomal and lysosomal networks in mammalian cells.

scholarly journals MYADM regulates Rac1 targeting to ordered membranes required for cell spreading and migration

2011 ◽  
Vol 22 (8) ◽  
pp. 1252-1262 ◽  
Author(s):  
Juan F. Aranda ◽  
Natalia Reglero-Real ◽  
Leonor Kremer ◽  
Beatriz Marcos-Ramiro ◽  
Ana Ruiz-Sáenz ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Migration ◽  
Mammalian Cells ◽  
Cell Spreading ◽  
Membrane Domains ◽  
Membrane Raft ◽  
General Process ◽  
Membrane Protrusions ◽  
Differentiation Marker ◽  
And Migration

Membrane organization into condensed domains or rafts provides molecular platforms for selective recruitment of proteins. Cell migration is a general process that requires spatiotemporal targeting of Rac1 to membrane rafts. The protein machinery responsible for making rafts competent to recruit Rac1 remains elusive. Some members of the MAL family of proteins are involved in specialized processes dependent on this type of membrane. Because condensed membrane domains are a general feature of the plasma membrane of all mammalian cells, we hypothesized that MAL family members with ubiquitous expression and plasma membrane distribution could be involved in the organization of membranes for cell migration. We show that myeloid-associated differentiation marker (MYADM), a protein with unique features within the MAL family, colocalizes with Rac1 in membrane protrusions at the cell surface and distributes in condensed membranes. MYADM knockdown (KD) cells had altered membrane condensation and showed deficient incorporation of Rac1 to membrane raft fractions and, similar to Rac1 KD cells, exhibited reduced cell spreading and migration. Results of rescue-of-function experiments by expression of MYADM or active Rac1L61 in cells knocked down for Rac1 or MYADM, respectively, are consistent with the idea that MYADM and Rac1 act on parallel pathways that lead to similar functional outcomes.

scholarly journals Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

2020 ◽  
Author(s):  
Miguel Miron-Mendoza ◽  
Dalia Vazquez ◽  
Nerea García-Rámila ◽  
W. Matthew Petroll ◽  
Hikaru R. Ikebe
Keyword(s):  
Leading Edge ◽  
Cell Spreading ◽  
Interconnected Network ◽  
Corneal Injury ◽  
Corneal Fibroblasts ◽  
Track Formation ◽  
Tractional Forces ◽  
Highly Correlated ◽  
And Migration ◽  
Matrix Contraction

We previously reported that corneal fibroblasts within 3D fibrin matrices secrete, bind, and organize fibronectin into tracks that facilitate cell spreading and migration. Other cells use these fibronectin tracks as conduits, which leads to the development of an interconnected cell/fibronectin network. In this study, we investigate how cell induced reorganization of fibrin correlates with fibronectin track formation in response to two growth factors present during wound healing: PDGF BB, which stimulates cell spreading and migration; and TGFβ1, which stimulates cellular contraction and myofibroblast transformation. Both PDGF BB and TGFb1 stimulated global fibrin matrix contraction (P < 0.005), however cell and matrix patterning were different. We found that during PDGF BB induced cell spreading, fibronectin was organized simultaneously with the generation of tractional forces at the leading edge of pseudopodia. Over time this led to the formation of an interconnected network consisting of cells, fibronectin and compacted fibrin tracks. Following culture in TGFβ1, cells were less motile, produced significant local fibrin reorganization, and formed fewer cellular connections as compared to PDGF BB (P < 0.005). Although bands of compacted fibrin tracks developed in between neighboring cells, fibronectin labeling was not generally present along these tracks, and the correlation between fibrin and fibronectin labeling was significantly less than that observed in PDGF BB (P < 0.001). Taken together, our results show that cell-induced ECM reorganization can occur independently from fibronectin patterning. Nonetheless, both events seem to be coordinated, as corneal fibroblasts in PDGF BB secrete and organize fibronectin as they preferentially spread along compacted fibrin tracks between cells, producing an interconnected network in which cells, fibronectin and compacted fibrin tracks are highly correlated. This mechanism of patterning could contribute to the formation of organized cellular networks that have been observed following corneal injury and refractive surgery.

scholarly journals Phosphorylation of GMFγ by c-Abl coordinates lamellipodial and focal adhesion dynamics

2018 ◽  
Author(s):  
Brennan D. Gerlach ◽  
Guoning Liao ◽  
Kate Tubbesing ◽  
Alyssa C. Rezey ◽  
Ruping Wang ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Receptor Tyrosine Kinase ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Human Cell Line ◽  
Signaling Cascades ◽  
Phosphorylated Form ◽  
Maturation Factor ◽  
Associated Proteins ◽  
Syndrome Protein

During cell migration a critical interdependence between protrusion and focal adhesion dynamics is established and tightly regulated through signaling cascades. Here we demonstrate that c-Abl, a non-receptor tyrosine kinase, can control these migratory structures through the regulation of two actin-associated proteins, glia maturation factor-γ (GMFγ) and Neural Wiskott-Aldrich syndrome protein (N-WASP). Phosphorylation of GMFγ at tyrosine-104 by c-Abl directs activated N-WASP (pY256) to the leading edge, where it can promote protrusion extension. Non-phosphorylated GMFγ guides N-WASP (pY256) to maturing focal adhesions to enhance further growth. Antagonizing this signaling pathway through knockdown or mutation of tyrosine-104 to its non-phosphorylated form attenuates migration, whereas the phospho-mimic mutant GMFγ enhances migration, thus demonstrating c-Abl, GMFγ, and activated N-WASP (pY256) as a critical signaling cascade for regulating migration in a primary human cell line.

scholarly journals Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

2020 ◽  
Vol 7 (3) ◽  
pp. 89
Author(s):  
Miguel Miron-Mendoza ◽  
Dalia Vazquez ◽  
Nerea García-Rámila ◽  
Hikaru R. Ikebe ◽  
W. Matthew Petroll
Keyword(s):  
Leading Edge ◽  
Cell Spreading ◽  
Interconnected Network ◽  
Corneal Injury ◽  
Corneal Fibroblasts ◽  
Track Formation ◽  
Tractional Forces ◽  
Highly Correlated ◽  
And Migration ◽  
Matrix Contraction

We previously reported that corneal fibroblasts within 3D fibrin matrices secrete, bind, and organize fibronectin into tracks that facilitate cell spreading and migration. Other cells use these fibronectin tracks as conduits, which leads to the development of an interconnected cell/fibronectin network. In this study, we investigate how cell-induced reorganization of fibrin correlates with fibronectin track formation in response to two growth factors present during wound healing: PDGF BB, which stimulates cell spreading and migration; and TGFβ1, which stimulates cellular contraction and myofibroblast transformation. Both PDGF BB and TGFβ1 stimulated global fibrin matrix contraction (p < 0.005); however, the cell and matrix patterning were different. We found that, during PDGF BB-induced cell spreading, fibronectin was organized simultaneously with the generation of tractional forces at the leading edge of pseudopodia. Over time this led to the formation of an interconnected network consisting of cells, fibronectin and compacted fibrin tracks. Following culture in TGFβ1, cells were less motile, produced significant local fibrin reorganization, and formed fewer cellular connections as compared to PDGF BB (p < 0.005). Although bands of compacted fibrin tracks developed in between neighboring cells, fibronectin labeling was not generally present along these tracks, and the correlation between fibrin and fibronectin labeling was significantly less than that observed in PDGF BB (p < 0.001). Taken together, our results show that cell-induced extracellular matrix (ECM) reorganization can occur independently from fibronectin patterning. Nonetheless, both events seem to be coordinated, as corneal fibroblasts in PDGF BB secrete and organize fibronectin as they preferentially spread along compacted fibrin tracks between cells, producing an interconnected network in which cells, fibronectin and compacted fibrin tracks are highly correlated. This mechanism of patterning could contribute to the formation of organized cellular networks that have been observed following corneal injury and refractive surgery.

Configuration of human dendritic cell cytoskeleton by Rho GTPases, the WAS protein, and differentiation

Blood ◽  
2001 ◽  
Vol 98 (4) ◽  
pp. 1142-1149 ◽  
Author(s):  
Siobhan Burns ◽  
Adrian J. Thrasher ◽  
Michael P. Blundell ◽  
Laura Machesky ◽  
Gareth E. Jones
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Rho Gtpases ◽  
Leading Edge ◽  
Human Dendritic Cell ◽  
Related Protein ◽  
Concerted Action ◽  
Cellular Mechanisms ◽  
And Migration ◽  
Syndrome Protein

The cellular mechanisms that configure the cytoskeleton during migration of dendritic cells (DCs) are poorly understood. Immature DCs assemble specialized adhesion structures known as podosomes at their leading edge; these are associated with the localized recruitment of the Wiskott-Aldrich Syndrome protein (WASp) and the actin organizing actin-related protein 2/3 complex. In immature DCs lacking WASp, podosomes are absent, residual dysmorphic lamellipodia and filopodia are nonpolarized, and migration is severely compromised. Microinjection studies indicate that podosome assembly and polarization require concerted action of Cdc42, Rac, and Rho, thereby providing a link between sequential protrusive and adhesive activity. Formation of podosomes is restricted to cells with an immature phenotype, indicating a specific role for these structures during the early migratory phase.

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