scholarly journals The LIM protein Ajuba influences p130Cas localization and Rac1 activity during cell migration

2005 ◽  
Vol 168 (5) ◽  
pp. 813-824 ◽  
Author(s):  
Stephen J. Pratt ◽  
Holly Epple ◽  
Michael Ward ◽  
Yunfeng Feng ◽  
Vania M. Braga ◽  
...  

Cell migration requires extension of lamellipodia that are stabilized by formation of adhesive complexes at the leading edge. Both processes are regulated by signaling proteins recruited to nascent adhesive sites that lead to activation of Rho GTPases. The Ajuba/Zyxin family of LIM proteins are components of cellular adhesive complexes. We show that cells from Ajuba null mice are inhibited in their migration, without associated abnormality in adhesion to extracellular matrix proteins, cell spreading, or integrin activation. Lamellipodia production, or function, is defective and there is a selective reduction in the level and tyrosine phosphorylation of FAK, p130Cas, Crk, and Dock180 at nascent focal complexes. In response to migratory cues Rac activation is blunted in Ajuba null cells, as detected biochemically and by FRET analysis. Ajuba associates with the focal adhesion-targeting domain of p130Cas, and rescue experiments suggest that Ajuba acts upstream of p130Cas to localize p130Cas to nascent adhesive sites in migrating cells thereby leading to the activation of Rac.

2016 ◽  
Vol 44 (6) ◽  
pp. 1695-1700 ◽  
Author(s):  
Joseph H.R. Hetmanski ◽  
Jean-Marc Schwartz ◽  
Patrick T. Caswell

Metastasis, initially driven by cells migrating and invading through the local environment, leads to most cancer-associated deaths. Cells can use a variety of modes to move in vitro, all of which depend on Rho GTPases at some level. While traditionally it was thought that Rac1 activity drives protrusive lamellipodia at the leading edge of a polarised cell while RhoA drives rear retraction, more recent work in 3D microenvironments has revealed a much more complicated picture of GTPase dynamics. In particular, RhoA activity can dominate the leading edge polymerisation of actin to form filopodial actin-spike protrusions that drive more invasive cell migration. We recently described a potential mechanism to abrogate this pro-invasive localised leading edge Rac1 to RhoA switch via manipulation of a negative feedback loop that was revealed by adopting a logical modelling approach. Both challenging dogma and taking a formal, mathematical approach to understanding signalling involved in motility may be vital to harnessing harmful cell migration and preventing metastasis in future research.


2012 ◽  
Vol 199 (2) ◽  
pp. 331-345 ◽  
Author(s):  
Shujie Wang ◽  
Takashi Watanabe ◽  
Kenji Matsuzawa ◽  
Akira Katsumi ◽  
Mai Kakeno ◽  
...  

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.


Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2273
Author(s):  
Jimena Canales ◽  
Pablo Cruz ◽  
Nicolás Díaz ◽  
Denise Riquelme ◽  
Elías Leiva-Salcedo ◽  
...  

Cell migration is critical for several physiological and pathophysiological processes. It depends on the coordinated action of kinases, phosphatases, Rho-GTPases proteins, and Ca2+ signaling. Interestingly, ubiquitination events have emerged as regulatory elements of migration. Thus, the role of proteins involved in ubiquitination processes could be relevant to a complete understanding of pro-migratory mechanisms. KCTD5 is a member of Potassium Channel Tetramerization Domain (KCTD) proteins that have been proposed as a putative adaptor for Cullin3-E3 ubiquitin ligase and a novel regulatory protein of TRPM4 channels. Here, we study whether KCTD5 participates in cell migration-associated mechanisms, such as focal adhesion dynamics and cellular spreading. Our results show that KCTD5 CRISPR/Cas9- and shRNA-based depletion in B16-F10 cells promoted an increase in cell migration and cell spreading, and a decrease in the focal adhesion area, consistent with an increased focal adhesion disassembly rate. The expression of a dominant-negative mutant of Rho-GTPases Rac1 precluded the KCTD5 depletion-induced increase in cell spreading. Additionally, KCTD5 silencing decreased the serum-induced Ca2+ response, and the reversion of this with ionomycin abolished the KCTD5 knockdown-induced decrease in focal adhesion size. Together, these data suggest that KCTD5 acts as a regulator of cell migration by modulating cell spreading and focal adhesion dynamics through Rac1 activity and Ca2+ signaling, respectively.


2006 ◽  
Vol 176 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Erik Sahai ◽  
Raquel Garcia-Medina ◽  
Jacques Pouysségur ◽  
Emmanuel Vial

Rho GTPases participate in various cellular processes, including normal and tumor cell migration. It has been reported that RhoA is targeted for degradation at the leading edge of migrating cells by the E3 ubiquitin ligase Smurf1, and that this is required for the formation of protrusions. We report that Smurf1-dependent RhoA degradation in tumor cells results in the down-regulation of Rho kinase (ROCK) activity and myosin light chain 2 (MLC2) phosphorylation at the cell periphery. The localized inhibition of contractile forces is necessary for the formation of lamellipodia and for tumor cell motility in 2D tissue culture assays. In 3D invasion assays, and in in vivo tumor cell migration, the inhibition of Smurf1 induces a mesenchymal–amoeboid–like transition that is associated with a more invasive phenotype. Our results suggest that Smurf1 is a pivotal regulator of tumor cell movement through its regulation of RhoA signaling.


2021 ◽  
Author(s):  
Mei Lin ◽  
Honghong Sun ◽  
Svetlana A. Fayngerts ◽  
Peiwei Huangyang ◽  
Youhai H. Chen

More than half of human tumors exhibit aberrantly dysregulated phosphoinositide signaling, yet how this is controlled remains not fully understood. While somatic mutations of PI3K, PTEN and Ras account for many cases of the hyperactivated lipid signals, other mechanisms for these dysfunctions in cancer are also being discovered. We report here that TNFAIP8 interacts with PtdIns(4,5)P2 and PtdIns(3,4,5)P3 and is likely to be hijacked by cancer cells to facilitate directional migration during malignant transformation. TNFAIP8 maintains the quiescent cellular state by sequestering inactive Rho GTPases in the cytosolic pool, which can be set free upon chemoattractant activation at the leading edge. Consequently, loss of TNFAIP8 results in severe defects of chemotaxis and adhesion. Thus, TNFAIP8, whose expression can be induced by inflammatory cytokines such as TNFα from tumor microenvironment, represents a molecular bridge from inflammation to cancer by linking NF-κB pathway to phosphoinositide signaling. Our study on the conserved hydrophobic cavity structure will also advise in silico drug screening and development of new TNFAIP8-based strategies to combat malignant human diseases.


2019 ◽  
Author(s):  
J. Bui ◽  
D. E. Conway ◽  
R. L. Heise ◽  
S.H. Weinberg

ABSTRACTCell migration, a fundamental physiological process in which cells sense and move through their surrounding physical environment, plays a critical role in development and tissue formation, as well as pathological processes, such as cancer metastasis and wound healing. During cell migration, dynamics are governed by the bidirectional interplay between cell-generated mechanical forces and the activity of Rho GTPases, a family of small GTP-binding proteins that regulate actin cytoskeleton assembly and cellular contractility. These interactions are inherently more complex during the collective migration of mechanically coupled cells, due to the additional regulation of cell-cell junctional forces. In this study, we present a minimal modeling framework to simulate the interactions between mechanochemical signaling in individual cells and interactions with cell-cell junctional forces during collective cell migration. We find that migration of individual cells depends on the feedback between mechanical tension and Rho GTPase activity in a biphasic manner. During collective cell migration, waves of Rho GTPase activity mediate mechanical contraction/extension and thus synchronization throughout the tissue. Further, cell-cell junctional forces exhibit distinct spatial patterns during collective cell migration, with larger forces near the leading edge. Larger junctional force magnitudes are associated with faster collective cell migration and larger tissue size. Simulations of heterogeneous tissue migration exhibit a complex dependence on the properties of both leading and trailing cells. Computational predictions demonstrate that collective cell migration depends on both the emergent dynamics and interactions between cellular-level Rho GTPase activity and contractility, and multicellular-level junctional forces.


Author(s):  
Sungsoo Na

Cell migration is achieved by the dynamic feedback interactions between traction forces generated by the cell and exerted onto the underlying extracellular matrix (ECM), and intracellular mechano-chemical signaling pathways, e.g., Rho GTPase (RhoA, Rac1, and Cdc42) activities [1,2,3]. These components are differentially distributed within a cell, and thus the coordination between tractions and mechanotransduction (i.e, RhoA and Rac1 activities) must be implemented at a precise spatial and temporal order to achieve optimized, directed cell migration [4,5]. Recent studies have shown that focal adhesions at the leading edge exert strong tractions [6], and these traction sites are co-localized with focal adhesion sites [7]. Further, by using the fluorescence resonance energy transfer (FRET) technology coupled with genetically encoded biosensors, researchers reported that Rho GTPases, such as RhoA [8], Rac1 [9], and Cdc42 [10] are maximally activated at the leading edge, suggesting the leading edge of the cell as its common functional site for Rho GTPase activities. All these works, however, were done separately, and the relationship between tractions and mechanotransduction during cell migration has not been demonstrated directly because of the difficulty in simultaneously recording tractions and mechanotransduction in migrating cells, precluding direct comparison between these results. Furthermore, these studies have been conducted by monitoring cells on glass coverslips, the stiffness of which is ∼ 65 giga pascal (GPa), at least three to six order higher than the physiological range of ECM stiffness. Although it is increasingly accepted that ECM stiffness influences cell migration, it is not known exactly how physiologically relevant ECM stiffness (order of kPa range) affects the dynamics of RhoA and Rac1 activities. For a complete understanding of the mechanism of mechano-chemical signaling in the context of cell migration, the dynamics and interplay between biomechanical (e.g., tractions) and biochemical (e.g., Rho GTPase) activities should be visualized within the physiologically relevant range of ECM stiffness.


2013 ◽  
Vol 24 (12) ◽  
pp. 1882-1894 ◽  
Author(s):  
Matthew C. Jones ◽  
Kazuya Machida ◽  
Bruce J. Mayer ◽  
Christopher E. Turner

The Rho family of GTPases plays an important role in coordinating dynamic changes in the cell migration machinery after integrin engagement with the extracellular matrix. Rho GTPases are activated by guanine nucleotide exchange factors (GEFs) and negatively regulated by GTPase-activating proteins (GAPs). However, the mechanisms by which GEFs and GAPs are spatially and temporally regulated are poorly understood. Here the activity of the proto-oncogene Vav2, a GEF for Rac1, RhoA, and Cdc42, is shown to be regulated by a phosphorylation-dependent interaction with the ArfGAP PKL (GIT2). PKL is required for Vav2 activation downstream of integrin engagement and epidermal growth factor (EGF) stimulation. In turn, Vav2 regulates the subsequent redistribution of PKL and the Rac1 GEF β-PIX to focal adhesions after EGF stimulation, suggesting a feedforward signaling loop that coordinates PKL-dependent Vav2 activation and PKL localization. Of interest, Vav2 is required for the efficient localization of PKL and β-PIX to the leading edge of migrating cells, and knockdown of Vav2 results in a decrease in directional persistence and polarization in migrating cells, suggesting a coordination between PKL/Vav2 signaling and PKL/β-PIX signaling during cell migration.


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuan Cao ◽  
Tomonori Kaneko ◽  
Jenny S. Li ◽  
An-Dong Liu ◽  
Courtney Voss ◽  
...  

Abstract Although cell migration plays a central role in development and disease, the underlying molecular mechanism is not fully understood. Here we report that a phosphorylation-mediated molecular switch comprising deleted in liver cancer 1 (DLC1), tensin-3 (TNS3), phosphatase and tensin homologue (PTEN) and phosphoinositide-3-kinase (PI3K) controls the spatiotemporal activation of the small GTPases, Rac1 and RhoA, thereby initiating directional cell migration induced by growth factors. On epidermal growth factor (EGF) or platelet-derived growth factor (PDGF) stimulation, TNS3 and PTEN are phosphorylated at specific Thr residues, which trigger the rearrangement of the TNS3–DLC1 and PTEN–PI3K complexes into the TNS3–PI3K and PTEN–DLC1 complexes. Subsequently, the TNS3–PI3K complex translocates to the leading edge of a migrating cell to promote Rac1 activation, whereas PTEN–DLC1 translocates to the posterior for localized RhoA activation. Our work identifies a core signalling mechanism by which an external motility stimulus is coupled to the spatiotemporal activation of Rac1 and RhoA to drive directional cell migration.


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