scholarly journals Molecular basis for Ras suppressor-1 recruitment to focal adhesions and stabilization of consensus adhesome complex

2021 ◽  
Author(s):  
Koichi Fukuda ◽  
Fan Lu ◽  
Jun Qin

AbstractRas suppressor-1 (Rsu-1) is a leucine-rich repeat (LRR)-containing protein that is crucial for regulating fundamental cell adhesion processes and tumor development. Rsu-1 interacts with a zinc-finger type multi LIM domain-containing adaptor protein PINCH-1 involved in the integrin-mediated consensus adhesome but not with highly homologous isoform PINCH-2. However, the structural basis for such specific interaction and regulatory mechanism remains unclear. Here, we determined the crystal structures of Rsu-1 and its complex with the PINCH-1 LIM4-5 domains. Rsu-1 displays an arc-shaped solenoid architecture with eight LRRs shielded by the N- and C-terminal capping modules. We show that a large conserved concave surface of the Rsu-1 LRR domain recognizes the PINCH-1 LIM5 domain, and that the C-terminal non-LIM region of PINCH-2 but not PINCH-1 sterically disfavors the Rsu-1 binding. We further show that Rsu-1 can be assembled, via PINCH-1-binding, into a tight hetero-pentamer complex comprising Rsu-1, PINCH-1, ILK, Parvin, and Kindlin-2 that constitute a major consensus integrin adhesome crucial for focal adhesion assembly. Consistently, our mutagenesis and cell biological data consolidate the significance of the Rsu-1/PINCH-1 interaction in focal adhesion assembly and cell spreading. Our results provide a crucial molecular insight into Rsu-1-mediated cell adhesion with implication on how it may regulate tumorigenic growth.

1998 ◽  
Vol 9 (7) ◽  
pp. 1803-1816 ◽  
Author(s):  
Michael C. Brown ◽  
Joseph A. Perrotta ◽  
Christopher E. Turner

We have previously shown that the LIM domains of paxillin operate as the focal adhesion (FA)-targeting motif of this protein. In the current study, we have identified the capacity of paxillin LIM2 and LIM3 to serve as binding sites for, and substrates of serine/threonine kinases. The activities of the LIM2- and LIM3-associated kinases were stimulated after adhesion of CHO.K1 cells to fibronectin; consequently, a role for LIM domain phosphorylation in regulating the subcellular localization of paxillin after adhesion to fibronectin was investigated. An avian paxillin-CHO.K1 model system was used to explore the role of paxillin phosphorylation in paxillin localization to FAs. We found that mutations of paxillin that mimicked LIM domain phosphorylation accelerated fibronectin-induced localization of paxillin to focal contacts. Further, blocking phosphorylation of the LIM domains reduced cell adhesion to fibronectin, whereas constitutive LIM domain phosphorylation significantly increased the capacity of cells to adhere to fibronectin. The potentiation of FA targeting and cell adhesion to fibronectin was specific to LIM domain phosphorylation as mutation of the amino-terminal tyrosine and serine residues of paxillin that are phosphorylated in response to fibronectin adhesion had no effect on the rate of FA localization or cell adhesion. This represents the first demonstration of the regulation of protein localization through LIM domain phosphorylation and suggests a novel mechanism of regulating LIM domain function. Additionally, these results provide the first evidence that paxillin contributes to “inside-out” integrin-mediated signal transduction.


2010 ◽  
pp. n/a-n/a ◽  
Author(s):  
David W. Dumbauld ◽  
Heungsoo Shin ◽  
Nathan D. Gallant ◽  
Kristin E. Michael ◽  
Harish Radhakrishna ◽  
...  

2003 ◽  
Vol 371 (2) ◽  
pp. 565-571 ◽  
Author(s):  
José V. MOYANO ◽  
Alfredo MAQUEDA ◽  
Juan P. ALBAR ◽  
Angeles GARCIA-PARDO

Cell adhesion to fibronectin results in formation of actin stress fibres and focal adhesions. In fibroblasts, this response requires two co-operative signals provided by interactions of the RGD sequence with α5β1 integrin and the heparin-binding domain II (Hep II) domain with syndecan-4. Within Hep II, this activity was mapped to repeat III13 and to the peptide FN-C/H-V(WQPPRARITGY, repeat III14). We previously described that the synthetic heparin-binding peptide/III5 (HBP/III5) (WTPPRAQITGYRLTVGLTRR, repeat III5) binds heparin and mediates cell adhesion via chondroitin sulphate proteoglycans. We have now studied whether HBP/III5 co-operates with α5β1 and drives a full cytoskeletal response in melanoma cells. SKMEL-178 cells attached and spread on the RGD-containing FNIII7–FNIII10 (FNIII7–10) fragment, but did not form stress fibres or focal adhesions. Co-immobilization of HBP/III5 with FNIII7–10 or adding soluble HBP/III5 to cells prespread on FNIII7–10, effectively induced these structures. Cell transfection with dominant-negative N19RhoA, a member of the small GTPase family, abolished the HBP/III5 effect. Both chondroitinase and heparitinase diminished focal adhesions, indicating that both types of proteoglycans bound HBP/III5 in melanoma cells. We have mapped the active sequence of HBP/III5 to YRLTVGLTRR, which is a novel sequence in fibronectin with focal-adhesion-promoting activity. The last two arginine (R) residues of this sequence are required for activity, since their replacement by alanine completely abrogated the HBP/III5 cytoskeletal effect. Moreover, this sequence is also active in the context of large fibronectin fragments. Our results establish that the Hep III region provides co-operative signals to α5β1 for the progression of the cytoskeletal response and that these include activation of RhoA.


1994 ◽  
Vol 5 (9) ◽  
pp. 977-988 ◽  
Author(s):  
S Kawaguchi ◽  
J M Bergelson ◽  
R W Finberg ◽  
M E Hemler

Chinese hamster ovary (CHO) cells transfected with the integrin alpha 2 subunit formed a stable VLA-2 heterodimer that mediated cell adhesion to collagen. Within CHO cells spread on collagen, but not fibronectin, wild-type alpha 2 subunit localized into focal adhesion complexes (FACs). In contrast, alpha 2 with a deleted cytoplasmic domain was recruited into FACs whether CHO cells were spread on collagen or fibronectin. Thus, as previously seen for other integrins, the alpha 2 cytoplasmic domain acts as a negative regulator, preventing indiscriminate integrin recruitment into FACs. Notably, ligand-independent localization of the VLA-2 alpha 2 subunit into FACs was partially prevented if only one or two amino acids were present in the alpha 2 cytoplasmic domain (beyond the conserved GFFKR motif) and was completely prevented by four to seven amino acids. The addition of two alanine residues (added to GFFKR) also partially prevented ligand-independent localization. In a striking inverse correlation, the same mutants showing increased ligand-independent recruitment into FACs exhibited diminished alpha 2-dependent adhesion to collagen. Thus, control of VLA-2 localization may be closely related to the suppression of cell adhesion to collagen. In contrast to FAC localization and collagen adhesion results, VLA-2-dependent binding and infection by echovirus were unaffected by either alpha 2 cytoplasmic domain deletion or exchange with other cytoplasmic domains.


2009 ◽  
Vol 296 (3) ◽  
pp. C414-C421 ◽  
Author(s):  
Shannon M. Gallagher ◽  
John J. Castorino ◽  
Nancy J. Philp

Monocarboxylate transporter (MCT) 4 is a heteromeric proton-coupled lactate transporter that is noncovalently linked to the extracellular matrix metalloproteinase inducer CD147 and is typically expressed in glycolytic tissues. There is increasing evidence to suggest that ion transporters are part of macromolecular complexes involved in regulating β1-integrin adhesion and cell movement. In the present study we examined whether MCTs play a role in cell migration through their interaction with β1-integrin. Using reciprocal coimmunoprecipitation assays, we found that β1-integrin selectively associated with MCT4 in ARPE-19 and MDCK cells, two epithelial cell lines that express both MCT1 and MCT4. In polarized monolayers of ARPE-19 cells, MCT4 and β1-integrin colocalized to the basolateral membrane, while both proteins were found in the leading edge lamellapodia of migrating cells. In scratch-wound assays, MCT4 knockdown slowed migration and increased focal adhesion size. In contrast, silencing MCT1 did not alter the rate of cell migration or focal adhesion size. Taken together, our findings suggest that the specific interaction of MCT4 with β1-integrin may regulate cell migration through modulation of focal adhesions.


1998 ◽  
Vol 111 (6) ◽  
pp. 793-802 ◽  
Author(s):  
D. Dogic ◽  
P. Rousselle ◽  
M. Aumailley

Laminin 1 (alpha1beta1gamma1) and laminin 5 (alpha3beta3gamma2) induce cell adhesion with different involvement of integrins: both are ligands for the alpha6beta1 integrin, while alpha3beta1 integrin has affinity for laminin 5 only. These two laminin isoforms therefore provide good models to investigate whether alpha3beta1 and alpha6beta1 integrins play different roles in signal transduction and in focal adhesion formation. Laminin 1 or 5 induced adhesion of normal human skin fibroblasts to a similar extent but promoted different overall cell shapes. On laminin 1 the fibroblasts formed mainly filopodia-like structures, while on laminin 5 they developed lamellipodias. Staining of fibrillar actin with fluorescein-phalloidin revealed a similar organisation of the actin cytoskeleton on both substrates. However, integrin subunits and several cytoskeletal linker proteins, including vinculin, talin, and paxillin, showed an isoform-specific arrangement into focal adhesions. On laminin 1 they were recruited into thick and short aggregates localized at the termini of actin stress fibers, while on laminin 5 they appeared as dots or streaks clustered on a long portion of actin microfilaments. To test whether the differing affinity of laminin 1 or 5 for alpha3beta1 integrin would explain the formation of morphologically different focal adhesions, cells were seeded on laminin 1 under conditions in which alpha3beta1 integrins were occupied by a function-blocking antibody. This resulted in the formation of focal adhesions similar to that observed on laminin 5, where the integrin is occupied by its natural ligand. These results provide the first evidence for a cross-talk between alpha3beta1 and alpha6beta1 integrins and indicate that occupancy of alpha3beta1 integrins results in a trans-dominant regulation of alpha6beta1 integrin clustering and of focal adhesions. It suggests that recruitment of integrins and cytoskeletal linker proteins are laminin isoform-specific and that tissue specific expression of laminin isoforms might modulate cell behavior by the activation of distinct sets of integrins and by the induction of distinct molecular assemblies within the cell adhesion signaling complexes.


1999 ◽  
Vol 112 (2) ◽  
pp. 181-190 ◽  
Author(s):  
S.M. Thomas ◽  
M. Hagel ◽  
C.E. Turner

Paxillin is a focal adhesion scaffolding protein which was originally identified as a substrate of the oncogenic tyrosine kinase, v-src. Paxillin has been proposed to be involved in regulation of focal adhesion dynamics. Two alternatively spliced mouse paxillin cDNAs were cloned and in the process, a paxillin-related protein, Hic-5, was also identified. Cloning and characterization of Hic-5 indicates that this protein shares extensive homology with paxillin. Although Hic-5 was originally characterized as a TGF-beta-inducible gene and proposed to be a transcription factor involved in senescence, the studies here demonstrate that Hic-5 is localized to focal adhesion in REF52 cells and can interact with the focal adhesion proteins, Fak, Frnk, and vinculin. In addition, like paxillin, Hic-5 can bind to a negative regulator of Src PTKs, csk but does not bind to the adaptor protein Crk. Like paxillin, localization of this protein to focal adhesions is mediated primarily by the LIM domains; however, sequences outside the LIM domains also play a minor role in focal adhesion targeting. These results suggest that Hic-5 like paxillin could be involved in regulation of focal adhesion dynamics and raise the possibility that Hic-5 and paxillin could have overlapping or opposing functions in the overall regulation of cell growth and differentiation.


2007 ◽  
Vol 179 (4) ◽  
pp. 2397-2407 ◽  
Author(s):  
Yuichi Sekine ◽  
Satoshi Tsuji ◽  
Osamu Ikeda ◽  
Kenji Sugiyma ◽  
Kenji Oritani ◽  
...  

2018 ◽  
Author(s):  
Bertille Bance ◽  
Shailaja Seetharaman ◽  
Cécile Leduc ◽  
Batiste Boëda ◽  
Sandrine Etienne-Manneville

AbstractMicrotubules play a crucial role in mesenchymal migration by controlling cell polarity and the turnover of cell adhesive structures on the extracellular matrix. The polarized functions of microtubules imply that microtubules are locally regulated. Here, we investigated the regulation and role of two major tubulin post-translational modifications, acetylation and detyrosination, which have been associated with stable microtubules. Using primary astrocytes in a wound healing assay, we show that these tubulin modifications are independently regulated during cell polarization and differently affect cell migration. In contrast to microtubule detyrosination, αTAT1-mediated microtubule acetylation increases in the vicinity of focal adhesions and promotes cell migration. We further demonstrate that αTAT1 increases focal adhesion turnover by promoting Rab6-positive vesicle fusion at focal adhesions. Our results highlight the specificity of microtubule post-translational modifications and bring new insight into the regulatory functions of tubulin acetylation.


2000 ◽  
Vol 151 (7) ◽  
pp. 1435-1448 ◽  
Author(s):  
Sotiris N. Nikolopoulos ◽  
Christopher E. Turner

Paxillin is a focal adhesion adapter protein involved in the integration of growth factor– and adhesion-mediated signal transduction pathways. Paxillin LD motifs have been demonstrated to bind to several proteins associated with remodeling of the actin cytoskeleton including the focal adhesion kinase, vinculin, and a complex of proteins comprising p95PKL, PIX, and PAK (Turner, C.E., M.C. Brown, J.A. Perrotta, M.C. Riedy, S.N. Nikolopoulos, A.R. McDonald, S. Bagrodia, S. Thomas, and P.S. Leventhal. 1999. J. Cell Biol. 145:851–863). In this study, we report the cloning and initial characterization of a new paxillin LD motif–binding protein, actopaxin. Analysis of the deduced amino acid sequence of actopaxin reveals a 42-kD protein with two calponin homology domains and a paxillin-binding subdomain (PBS). Western blotting identifies actopaxin as a widely expressed protein. Actopaxin binds directly to both F-actin and paxillin LD1 and LD4 motifs. It exhibits robust focal adhesion localization in several cultured cell types but is not found along the length of the associated actin-rich stress fibers. Similar to paxillin, it is absent from actin-rich cell–cell adherens junctions. Also, actopaxin colocalizes with paxillin to rudimentary focal complexes at the leading edge of migrating cells. An actopaxin PBS mutant incapable of binding paxillin in vitro cannot target to focal adhesions when expressed in fibroblasts. In addition, ectopic expression of the PBS mutant and/or the COOH terminus of actopaxin in HeLa cells resulted in substantial reduction in adhesion to collagen. Together, these results suggest an important role for actopaxin in integrin-dependent remodeling of the actin cytoskeleton during cell motility and cell adhesion.


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