Cytoskeletal dynamics in rabbit synovial fibroblasts: II. Reformation of stress fibers in cells rounded by treatment with collagenase-lnducing agents

1990 ◽  
Vol 16 (2) ◽  
pp. 121-132 ◽  
Author(s):  
Judith Aggeler
Keyword(s):  
Synovial Fibroblasts ◽  
Stress Fibers ◽  
Cytoskeletal Dynamics ◽  
In Cells

scholarly journals Epithelial Protein Lost in Neoplasm, EPLIN, the Cellular and Molecular Prospects in Cancers

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1038
Author(s):  
Jianyuan Zeng ◽  
Wen G. Jiang ◽  
Andrew J. Sanders
Keyword(s):  
The Body ◽  
Early Years ◽  
Actin Binding ◽  
Cell Cycle Gene ◽  
Lim Domain ◽  
The Past ◽  
Concise Review ◽  
Cancerous Cell ◽  
Cytoskeletal Dynamics ◽  
In Cells

Epithelial Protein Lost In Neoplasm (EPLIN), also known as LIMA1 (LIM Domain And Actin Binding 1), was first discovered as a protein differentially expressed in normal and cancerous cell lines. It is now known to be key to the progression and metastasis of certain solid tumours. Despite a slow pace in understanding the biological role in cells and body systems, as well as its clinical implications in the early years since its discovery, recent years have witnessed a rapid progress in understanding the mechanisms of this protein in cells, diseases and indeed the body. EPLIN has drawn more attention over the past few years with its roles expanding from cell migration and cytoskeletal dynamics, to cell cycle, gene regulation, angiogenesis/lymphangiogenesis and lipid metabolism. This concise review summarises and discusses the recent progress in understanding EPLIN in biological processes and its implications in cancer.

scholarly journals Actin-depolymerizing Factor and Cofilin-1 Play Overlapping Roles in Promoting Rapid F-Actin Depolymerization in Mammalian Nonmuscle Cells

2005 ◽  
Vol 16 (2) ◽  
pp. 649-664 ◽  
Author(s):  
Pirta Hotulainen ◽  
Eija Paunola ◽  
Maria K. Vartiainen ◽  
Pekka Lappalainen
Keyword(s):  
Cell Motility ◽  
Actin Filament ◽  
Actin Filaments ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Depolymerizing Factor ◽  
Cytoskeletal Dynamics ◽  
Nonmuscle Cells ◽  
In Cells

Actin-depolymerizing factor (ADF)/cofilins are small actin-binding proteins found in all eukaryotes. In vitro, ADF/cofilins promote actin dynamics by depolymerizing and severing actin filaments. However, whether ADF/cofilins contribute to actin dynamics in cells by disassembling “old” actin filaments or by promoting actin filament assembly through their severing activity is a matter of controversy. Analysis of mammalian ADF/cofilins is further complicated by the presence of multiple isoforms, which may contribute to actin dynamics by different mechanisms. We show that two isoforms, ADF and cofilin-1, are expressed in mouse NIH 3T3, B16F1, and Neuro 2A cells. Depleting cofilin-1 and/or ADF by siRNA leads to an accumulation of F-actin and to an increase in cell size. Cofilin-1 and ADF seem to play overlapping roles in cells, because the knockdown phenotype of either protein could be rescued by overexpression of the other one. Cofilin-1 and ADF knockdown cells also had defects in cell motility and cytokinesis, and these defects were most pronounced when both ADF and cofilin-1 were depleted. Fluorescence recovery after photobleaching analysis and studies with an actin monomer-sequestering drug, latrunculin-A, demonstrated that these phenotypes arose from diminished actin filament depolymerization rates. These data suggest that mammalian ADF and cofilin-1 promote cytoskeletal dynamics by depolymerizing actin filaments and that this activity is critical for several processes such as cytokinesis and cell motility.

scholarly journals Focal adhesion kinase modulates tension signaling to control actin and focal adhesion dynamics

2007 ◽  
Vol 176 (5) ◽  
pp. 667-680 ◽  
Author(s):  
Markus Schober ◽  
Srikala Raghavan ◽  
Maria Nikolova ◽  
Lisa Polak ◽  
H. Amalia Pasolli ◽  
...  
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Focal Adhesions ◽  
Cellular Responses ◽  
Stress Fibers ◽  
Integrin Signaling ◽  
Cytoskeletal Dynamics ◽  
Skin Epidermis

In response to αβ1 integrin signaling, transducers such as focal adhesion kinase (FAK) become activated, relaying to specific machineries and triggering distinct cellular responses. By conditionally ablating Fak in skin epidermis and culturing Fak-null keratinocytes, we show that FAK is dispensable for epidermal adhesion and basement membrane assembly, both of which require αβ1 integrins. FAK is also dispensible for proliferation/survival in enriched medium. In contrast, FAK functions downstream of αβ1 integrin in regulating cytoskeletal dynamics and orchestrating polarized keratinocyte migration out of epidermal explants. Fak-null keratinocytes display an aberrant actin cytoskeleton, which is tightly associated with robust, peripheral focal adhesions and microtubules. We find that without FAK, Src, p190RhoGAP, and PKL–PIX–PAK, localization and/or activation at focal adhesions are impaired, leading to elevated Rho activity, phosphorylation of myosin light chain kinase, and enhanced tensile stress fibers. We show that, together, these FAK-dependent activities are critical to control the turnover of focal adhesions, which is perturbed in the absence of FAK.

scholarly journals SPARC, a secreted protein associated with morphogenesis and tissue remodeling, induces expression of metalloproteinases in fibroblasts through a novel extracellular matrix-dependent pathway.

1993 ◽  
Vol 121 (6) ◽  
pp. 1433-1444 ◽  
Author(s):  
P M Tremble ◽  
T F Lane ◽  
E H Sage ◽  
Z Werb
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Tissue Remodeling ◽  
Synovial Fibroblasts ◽  
Collagen Type Iv ◽  
Secreted Protein ◽  
Type Iv ◽  
Fibronectin Fragments ◽  
Domain Iii ◽  
In Cells

SPARC (osteonectin/BM40) is a secreted protein that modifies the interaction of cells with extracellular matrix (ECM). When we added SPARC to cultured rabbit synovial fibroblasts and analyzed the secreted proteins, we observed an increase in the expression of three metalloproteinases--collagenase, stromelysin, and the 92-kD gelatinase--that together can degrade both interstitial and basement membrane matrices. We further characterized the regulation of one of these metalloproteinases, collagenase, and showed that both collagenase mRNA and protein are upregulated in fibroblasts treated with SPARC. Experiments with synthetic SPARC peptides indicated that a region in the neutral alpha-helical domain III of the SPARC molecule, which previously had no described function, was involved in the regulation of collagenase expression by SPARC. A sequence in the carboxyl-terminal Ca(2+)-binding domain IV exhibited similar activity, but to a lesser extent. SPARC induced collagenase expression in cells plated on collagen types I, II, III, and V, and vitronectin, but not on collagen type IV. SPARC also increased collagenase expression in fibroblasts plated on ECM produced by smooth muscle cells, but not in fibroblasts plated on a basement membrane-like ECM from Engelbreth-Holm-Swarm sarcoma. Collagenase was induced within 4 h in cells treated with phorbol diesters or plated on fibronectin fragments, but was induced after 8 h in cells treated with SPARC. A number of proteins were transiently secreted by SPARC-treated cells within 6 h of treatment. Conditioned medium that was harvested from cultures 7 h after the addition of SPARC, and depleted of residual SPARC, induced collagenase expression in untreated fibroblasts; thus, part of the regulation of collagenase expression by SPARC appears to be indirect and proceeds through a secreted intermediate. Because the interactions of cells with ECM play an important role in regulation of cell behavior and tissue morphogenesis, these results suggest that molecules like SPARC are important in modulating tissue remodeling and cell-ECM interactions.

scholarly journals Crawling from soft to stiff matrix polarizes the cytoskeleton and phosphoregulates myosin-II heavy chain

2012 ◽  
Vol 199 (4) ◽  
pp. 669-683 ◽  
Author(s):  
Matthew Raab ◽  
Joe Swift ◽  
P.C. Dave P. Dingal ◽  
Palak Shah ◽  
Jae-Won Shin ◽  
...  
Keyword(s):  
Stem Cells ◽  
Myosin Ii ◽  
Stress Fibers ◽  
Site Specific ◽  
Soft Matrix ◽  
3D Collagen ◽  
The Difference ◽  
Rigid Surfaces ◽  
Tissue Matrix ◽  
In Cells

On rigid surfaces, the cytoskeleton of migrating cells is polarized, but tissue matrix is normally soft. We show that nonmuscle MIIB (myosin-IIB) is unpolarized in cells on soft matrix in 2D and also within soft 3D collagen, with rearward polarization of MIIB emerging only as cells migrate from soft to stiff matrix. Durotaxis is the tendency of cells to crawl from soft to stiff matrix, and durotaxis of primary mesenchymal stem cells (MSCs) proved more sensitive to MIIB than to the more abundant and persistently unpolarized nonmuscle MIIA (myosin-IIA). However, MIIA has a key upstream role: in cells on soft matrix, MIIA appeared diffuse and mobile, whereas on stiff matrix, MIIA was strongly assembled in oriented stress fibers that MIIB then polarized. The difference was caused in part by elevated phospho-S1943–MIIA in MSCs on soft matrix, with site-specific mutants revealing the importance of phosphomoderated assembly of MIIA. Polarization is thus shown to be a highly regulated compass for mechanosensitive migration.

scholarly journals Cell shape, spreading symmetry, and the polarization of stress-fibers in cells

2010 ◽  
Vol 22 (19) ◽  
pp. 194110 ◽  
Author(s):  
A Zemel ◽  
F Rehfeldt ◽  
A E X Brown ◽  
D E Discher ◽  
S A Safran
Keyword(s):  
Cell Shape ◽  
Stress Fibers ◽  
In Cells

scholarly journals Plectin sidearms mediate interaction of intermediate filaments with microtubules and other components of the cytoskeleton.

1996 ◽  
Vol 135 (4) ◽  
pp. 991-1007 ◽  
Author(s):  
T M Svitkina ◽  
A B Verkhovsky ◽  
G G Borisy
Keyword(s):  
Transgenic Mice ◽  
Mammalian Cell ◽  
Intermediate Filaments ◽  
Myosin Ii ◽  
Immunogold Labeling ◽  
Stress Fibers ◽  
Cross Links ◽  
Membrane Components ◽  
In Cells

By immunogold labeling, we demonstrate that "millipede-like" structures seen previously in mammalian cell cytoskeletons after removal of actin by treatment with gelsolin are composed of the cores of vimentin IFs with sidearms containing plectin. These plectin sidearms connect IFs to microtubules, the actin-based cytoskeleton and possibly membrane components. Plectin binding to microtubules was significantly increased in cells from transgenic mice lacking IFs and was reversed by microinjection of exogenous vimentin. These results suggest the existence of a pool of plectin which preferentially associates with IFs but may also be competed for by microtubules. The association of IFs with microtubules did not show a preference for Glu-tubulin. Nor did it depend upon the presence of MAP4 since plectin links were retained after specific immunodepletion of MAP4. The association of IFs with stress fibers survived actin depletion by gelsolin suggesting that myosin II minifilaments or components closely associated with them may play a role as plectin targets. Our results provide direct structural evidence for the hypothesis that plectin cross-links elements of the cytoskeleton thus leading to integration of the cytoplasm.

scholarly journals Stress fiber strain recognition by the LIM protein testin is cryptic and mediated by RhoA

2021 ◽  
pp. mbc.E21-03-0156
Author(s):  
Stefano Sala ◽  
Patrick W. Oakes
Keyword(s):  
Actin Cytoskeleton ◽  
Focal Adhesions ◽  
Stress Fibers ◽  
Lim Domain ◽  
Lim Domains ◽  
Lim Domain Protein ◽  
The Family ◽  
Domain Protein ◽  
Cytoskeletal Elements ◽  
In Cells

The actin cytoskeleton is a key regulator of mechanical processes in cells. The family of LIM domain proteins have recently emerged as important mechanoresponsive cytoskeletal elements capable of sensing strain in the actin cytoskeleton. The mechanisms regulating this mechanosensitive behavior, however, remain poorly understood. Here we show that the LIM domain protein testin is peculiar in that despite the full-length protein primarily appearing diffuse in the cytoplasm, the C-terminal LIM domains alone recognize focal adhesions and strained actin while the N-terminal domains alone recognize stress fibers. Phosphorylation mutations in the dimerization regions of testin, however, reveal its mechanosensitivity and cause it to relocate to focal adhesions and sites of strain in the actin cytoskeleton. Finally, we demonstrate activated RhoA causes testin to adorn stress fibers and become mechanosensitive. Together, our data show that testin's mechanoresponse is regulated in cells and provide new insights into LIM domain protein recognition of the actin cytoskeleton mechanical state. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text]

scholarly journals Stress fibers in cells in situ: immunofluorescence visualization with antiactin, antimyosin, and anti-alpha-actinin.

1982 ◽  
Vol 93 (3) ◽  
pp. 804-811 ◽  
Author(s):  
H R Byers ◽  
K Fujiwara
Keyword(s):  
Cultured Cells ◽  
Cellular Adhesion ◽  
Stress Fiber ◽  
Stress Fibers ◽  
Goldfish Carassius Auratus ◽  
Culture Cells ◽  
Central Regions ◽  
In Cells

Stress fiber-like patterns are visualized by indirect immunofluorescence in scleroblasts (fibroblasts) in situ on the scale of the common goldfish, Carassius auratus, using an affinity-purified antiactin, antimyosin, and anti-alpha-actinin. These fibers demonstrate the classical convergent and parallel patterns exhibited by stress fibers in tissue culture cells. Because the dimensions, the composition, and the pattern of distribution of these cytoplasmic fibers correspond well with those of stress fibers in cultured cells, we will call these fibers stress fibers also. The staining patterns with anti-alpha-actinin and antimyosin along the stress fibers often reveal a periodicity of 1-2 microM, identical to that found in cells in vitro. The majority of scleroblasts do not exhibit stress fiber staining and they are specifically located in the central regions of the scale. Stress fibers are present in scleroblasts residing on or near the edges or radical ridges of the scale. They are consistently orientated perpendicular to these structures; however, unlike microtubules, stress fibers show no co-alignment with collagen fibers of the scale. The finding that stress fibers are located in regions of the scale more subject to shearing forces may indicate their role in increased cellular adhesion to the substratum.

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