scholarly journals Rab18 regulates focal adhesion dynamics by interacting with kinectin-1 at the endoplasmic reticulum

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Noemi Antonella Guadagno ◽  
Azzurra Margiotta ◽  
Synne Arstad Bjørnestad ◽  
Linda Hofstad Haugen ◽  
Ingrid Kjos ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Focal Adhesion ◽  
Focal Adhesions ◽  
Molecular Switches ◽  
Underlying Mechanism ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Canonical Function ◽  
Dependent Transport

The members of the Rab family of small GTPases are molecular switches that regulate distinct steps in different membrane traffic pathways. In addition to this canonical function, Rabs can play a role in other processes, such as cell adhesion and motility. Here, we reveal the role of the small GTPase Rab18 as a positive regulator of directional migration in chemotaxis, and the underlying mechanism. We show that knockdown of Rab18 reduces the size of focal adhesions (FAs) and influences their dynamics. Furthermore, we found that Rab18, by directly interacting with the endoplasmic reticulum (ER)-resident protein kinectin-1, controls the anterograde kinesin-1–dependent transport of the ER required for the maturation of nascent FAs and protrusion orientation toward a chemoattractant. Altogether, our data support a model in which Rab18 regulates kinectin-1 transport toward the cell surface to form ER–FA contacts, thus promoting FA growth and cell migration during chemotaxis.

scholarly journals Arp2/3-Branched Actin Maintains an Active Pool of GTP-RhoA and Controls RhoA Abundance

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1264
Author(s):  
Yuxing Huang ◽  
Xin Yi ◽  
Chenlu Kang ◽  
Congying Wu
Keyword(s):  
Signal Transduction ◽  
Cell Motility ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Protein Abundance ◽  
Rhoa Activity ◽  
Cytoskeletal Dynamics ◽  
Active Pool ◽  
Spatiotemporal Control

Small GTPases regulate cytoskeletal dynamics, cell motility, and division under precise spatiotemporal control. Different small GTPases exhibit cross talks to exert feedback response or to act in concert during signal transduction. However, whether and how specific cytoskeletal components’ feedback to upstream signaling factors remains largely elusive. Here, we report an intriguing finding that disruption of the Arp2/3-branched actin specifically reduces RhoA activity but upregulates its total protein abundance. We further dissect the mechanisms underlying these circumstances and identify the altered cortactin/p190RhoGAP interaction and weakened CCM2/Smurf1 binding to be involved in GTP-RhoA reduction and total RhoA increase, respectively. Moreover, we find that cytokinesis defects induced by Arp2/3 inhibition can be rescued by activating RhoA. Our study reveals an intricate feedback from the actin cytoskeleton to the small GTPase. Our work highlights the role of Arp2/3-branched actin in signal transduction aside from its function in serving as critical cytoskeletal components to maintain cell morphology and motility.

scholarly journals Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

Reproduction ◽  
2012 ◽  
Vol 143 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Sayaka Koyanagi ◽  
Hiroko Hamasaki ◽  
Satoshi Sekiguchi ◽  
Kenshiro Hara ◽  
Yoshiyuki Ishii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Proteomic Analysis ◽  
Ubiquitin Proteasome System ◽  
Underlying Mechanism ◽  
Wild Type ◽  
Transmission Electron ◽  
Ubiquitin Proteasome

Maternal proteins are rapidly degraded by the ubiquitin–proteasome system during oocyte maturation in mice. Ubiquitin C-terminal hydrolase L1 (UCHL1) is highly and specifically expressed in mouse ova and is involved in the polyspermy block. However, the role of UCHL1 in the underlying mechanism of polyspermy block is poorly understood. To address this issue, we performed a comprehensive proteomic analysis to identify maternal proteins that were relevant to the role of UCHL1 in mouse ova using UCHL1-deficientgad. Furthermore, we assessed morphological features ingadmouse ova using transmission electron microscopy. NACHT, LRR, and PYD domain-containing (NALP) family proteins and endoplasmic reticulum (ER) chaperones were identified by proteomic analysis. We also found that the ‘maternal antigen that embryos require’ (NLRP5 (MATER)) protein level increased significantly ingadmouse ova compared with that in wild-type mice. In an ultrastructural study,gadmouse ova contained less ER in the cortex than in wild-type mice. These results provide new insights into the role of UCHL1 in the mechanism of polyspermy block in mouse ova.

scholarly journals Tension is required but not sufficient for focal adhesion maturation without a stress fiber template

2012 ◽  
Vol 196 (3) ◽  
pp. 363-374 ◽  
Author(s):  
Patrick W. Oakes ◽  
Yvonne Beckham ◽  
Jonathan Stricker ◽  
Margaret L. Gardel
Keyword(s):  
Focal Adhesion ◽  
Myosin Ii ◽  
Focal Adhesions ◽  
Stress Fiber ◽  
Matrix Remodeling ◽  
Force Transmission ◽  
Fiber Assembly ◽  
Wide Range ◽  
Structural Template

Focal adhesion composition and size are modulated in a myosin II–dependent maturation process that controls adhesion, migration, and matrix remodeling. As myosin II activity drives stress fiber assembly and enhanced tension at adhesions simultaneously, the extent to which adhesion maturation is driven by tension or altered actin architecture is unknown. We show that perturbations to formin and α-actinin 1 activity selectively inhibited stress fiber assembly at adhesions but retained a contractile lamella that generated large tension on adhesions. Despite relatively unperturbed adhesion dynamics and force transmission, impaired stress fiber assembly impeded focal adhesion compositional maturation and fibronectin remodeling. Finally, we show that compositional maturation of focal adhesions could occur even when myosin II–dependent cellular tension was reduced by 80%. We propose that stress fiber assembly at the adhesion site serves as a structural template that facilitates adhesion maturation over a wide range of tensions. This work identifies the essential role of lamellar actin architecture in adhesion maturation.

Role of tyrosine kinase pathways in ETB receptor activation of NHE3

1996 ◽  
Vol 271 (3) ◽  
pp. C763-C771 ◽  
Author(s):  
T. S. Chu ◽  
H. Tsuganezawa ◽  
Y. Peng ◽  
A. Cano ◽  
M. Yanagisawa ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Focal Adhesions ◽  
Integral Membrane Protein ◽  
Receptor Activation ◽  
Kinase C ◽  
Focal Adhesion Proteins ◽  
Etb Receptor

Endothelin-1 (ET-1) binding to ETB receptors increases the activity of the apical membrane Na+/H+ antiporter (NHE3) of renal proximal tubule and cultured OKP cells. In OKPETB6 cells, a clonal cell line of OKP cells that overexpresses ETB receptors, ET-1-induced increases in Na+/H+ antiporter activity are mediated 50% by Ca2(+)-dependent pathways and 50% by tyrosine kinase pathways. ET-1 induces tyrosine phosphorylation of proteins of 68, 110, 125, 130, and 210 kDa. ET-1-induced tyrosine phosphorylation is mediated by the ETB receptor and is not dependent on increases in cell Ca2+ or protein kinase C. The 68-, 110-, 125-, and 130-kDa phosphoproteins are cytosolic, whereas the 210-kDa phosphoprotein is an integral membrane protein. Immunoprecipitation studies showed that the 68-kDa protein is paxillin and the 125-kDa protein is p125FAK (focal adhesion kinase). Cytochalasin D, which disrupts focal adhesions, prevented ET-1-induced tyrosine phosphorylation of paxillin, p110, p125FAK, and p130 but did not prevent tyrosine phosphorylation of p210 and did not prevent ET-1-induced increases in Na+/H+ antiporter activity. Thus 50% of ETB receptor-induced Na+/H+ antiporter activation is mediated by tyrosine kinase pathways, possibly involving p210. ETB receptor activation also induces tyrosine phosphorylation of focal adhesion proteins, but this is not required for antiporter activation.

Small GTPases and Brucella entry into the endoplasmic reticulum

2012 ◽  
Vol 40 (6) ◽  
pp. 1348-1352 ◽  
Author(s):  
Xavier de Bolle ◽  
Jean-Jacques Letesson ◽  
Jean-Pierre Gorvel
Keyword(s):  
Endoplasmic Reticulum ◽  
Pathogenic Bacteria ◽  
Wild Type Strain ◽  
Specific Interaction ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Kinetics Of ◽  
Membrane Reservoir

A key determinant for intracellular pathogenic bacteria to ensure their virulence within host cells is their ability to bypass the endocytic pathway and to reach a safe niche of replication. In the case of Brucella, the bacterium targets the ER (endoplasmic reticulum) to create a replicating niche called the BCV (Brucella-containing vacuole). The ER is a suitable strategic place for pathogenic Brucella. Indeed, bacteria can be hidden from host cell defences to persist within the host, and they can take advantage of the membrane reservoir delivered by the ER to replicate. Interaction with the ER leads to the presence on the BCV of the GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and the small GTPase Rab2 known to be located on secretory vesicles that traffic between the ER and the Golgi apparatus. GAPDH and the small GTPase Rab2 controls Brucella replication at late times post-infection. A specific interaction between the human small GTPase Rab2 and a Brucella spp. protein named RicA was identified. Altered kinetics of intracellular trafficking and faster proliferation of the Brucella abortus ΔricA mutant was observed compared with the wild-type strain. RicA is the first reported effector with a proposed function for B. abortus.

scholarly journals A synthetic peptide from the heparin-binding domain III (repeats III4-5) of fibronectin promotes stress-fibre and focal-adhesion formation in melanoma cells

2003 ◽  
Vol 371 (2) ◽  
pp. 565-571 ◽  
Author(s):  
José V. MOYANO ◽  
Alfredo MAQUEDA ◽  
Juan P. ALBAR ◽  
Angeles GARCIA-PARDO
Keyword(s):  
Cell Adhesion ◽  
Focal Adhesion ◽  
Adhesion Formation ◽  
Focal Adhesions ◽  
Melanoma Cells ◽  
Small Gtpase ◽  
Binding Domain ◽  
Heparin Binding ◽  
Chondroitin Sulphate Proteoglycans ◽  
Heparin Binding Domain

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.

scholarly journals Tropomyosin Isoform Expression Regulates the Transition of Adhesions To Determine Cell Speed and Direction

2009 ◽  
Vol 29 (6) ◽  
pp. 1506-1514 ◽  
Author(s):  
Cuc T. T. Bach ◽  
Sarah Creed ◽  
Jessie Zhong ◽  
Maha Mahmassani ◽  
Galina Schevzov ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Actin Filaments ◽  
Feedback Loop ◽  
Cell Movement ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Mesenchymal Cell ◽  
Critical Determinant ◽  
Focal Complex

ABSTRACT The balance of transition between distinct adhesion types contributes to the regulation of mesenchymal cell migration, and the characteristic association of adhesions with actin filaments led us to question the role of actin filament-associating proteins in the transition between adhesive states. Tropomyosin isoform association with actin filaments imparts distinct filament structures, and we have thus investigated the role for tropomyosins in determining the formation of distinct adhesion structures. Using combinations of overexpression, knockdown, and knockout approaches, we establish that Tm5NM1 preferentially stabilizes focal adhesions and drives the transition to fibrillar adhesions via stabilization of actin filaments. Moreover, our data suggest that the expression of Tm5NM1 is a critical determinant of paxillin phosphorylation, a signaling event that is necessary for focal adhesion disassembly. Thus, we propose that Tm5NM1 can regulate the feedback loop between focal adhesion disassembly and focal complex formation at the leading edge that is required for productive and directed cell movement.

scholarly journals Response to Mechanical Cues by Interplay of YAP/TAZ Transcription Factors and Key Mechanical Checkpoints of the Cell:A Comprehensive Review

2021 ◽  
Vol 55 (1) ◽  
pp. 33-60
Keyword(s):  
Growth Factors ◽  
Focal Adhesions ◽  
Small Gtpases ◽  
Cell Behavior ◽  
Physical Factors ◽  
Binding Motif ◽  
Cell Behaviors ◽  
Key Factor ◽  
Scaffold Materials

Many factors including growth factors (GF), scaffold materials, and chemical and physical cues determine the cell behaviors. For many years, growth factors have been considered as the pivotal cell behavior regulators, whereas recent studies emphasize also the key role of physical factors such as mechanical forces, cell shape, surface topographies, and extracellular matrix (ECM) in regulating the cell proliferation, apoptosis, differentiation, etc. through mechanotransduction pathways. In this process, the cell morphology and mechanical properties of the cell's micro/ nano-environments and ECM can be conveyed to the nucleus by regulating transcriptional factors such as Yes-associated protein and transcriptional coactivator with PDZ-binding motif (TAZ). Generally, YAP/TAZ activity is considered as the key factor for the growth of whole organs, however, recent studies have also repeatedly addressed the role of YAP/TAZ in mechanotransduction. In this review, the biological functions of the YAP/TAZ pathway and its contribution to the mechanotransduction and cell behavior regulation in response to the mechanical cues have been summarized. Also, the role of key mechanical checkpoints in the cell including focal adhesions, cytoskeletal tension, Rho small GTPases, and nuclear membrane protein elements involved in the transfer of environmental mechanical cues from the cell surface to the nucleus and their effect in regulating the YAP/TAZ activity are discussed.

scholarly journals Activation of Rho-kinase and focal adhesion kinase regulates the organization of stress fibers and focal adhesions in the central part of fibroblasts

2017 ◽  
Author(s):  
Kazuo Katoh
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Adhesion Formation ◽  
Rho Kinase ◽  
Focal Adhesions ◽  
Fiber Formation ◽  
Stress Fibers ◽  
Focal Adhesion Formation ◽  
Specific Regulation

Specific regulation and activation of focal adhesion kinase (FAK) are thought to be important for focal adhesion formation, and activation of Rho-kinase has been suggested to play a role in determining the effects of FAK on the formation of stress fibers and focal adhesions. To clarify the role of FAK in stress fiber formation and focal adhesion organization, we examined the formation of new stress fibers and focal adhesions by activation of Rho-kinase in FAK knockout (FAK–/–) fibroblasts. FAK–/– cells were elliptical in shape, and showed reduced numbers of stress fibers and focal adhesions in the central part of the cells along with large focal adhesions in the peripheral regions. Activation of Rho-kinase in FAK–/– cells transiently increased the actin filaments in the cell center, but these did not form typical thick stress fibers. Moreover, only plaque-like structures as the origins of newly formed focal adhesions were observed in the center of the cell. Furthermore, introduction of an exogenous GFP-labeled FAK gene into FAK–/– cells resulted in increased numbers of stress fibers and focal adhesions in the center of the cells, which showed typical fibroblast morphology. These results indicated that FAK plays an important role in the formation of stress fibers and focal adhesions as well as in regulation of cell shape and morphology with the activation of Rho-kinase.

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