scholarly journals Lmna knockout mouse embryonic fibroblasts are less contractile than their wild-type counterparts

2017 ◽  
Vol 9 (8) ◽  
pp. 709-721 ◽  
Author(s):  
I. A. E. W. van Loosdregt ◽  
M. A. F. Kamps ◽  
C. W. J. Oomens ◽  
S. Loerakker ◽  
J. L. V. Broers ◽  
...  
Keyword(s):  
Knockout Mouse ◽  
Stress Fiber ◽  
Stress Generation ◽  
Actin Stress Fiber ◽  
Wild Type ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Contractile Stress ◽  
Fiber Organization

Lmna knockout causes an impaired actin stress fiber organization which results in a fivefold lower contractile stress generation.

scholarly journals The Mechanical Contribution of Vimentin to Cellular Stress Generation

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Inge A. E. W. van Loosdregt ◽  
Giulia Weissenberger ◽  
Marc P. F. H. L. van Maris ◽  
Cees W. J. Oomens ◽  
Sandra Loerakker ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Cellular Stress ◽  
Stress Fiber ◽  
Stress Generation ◽  
Stress Fibers ◽  
Adherent Cells ◽  
Wild Type ◽  
Contractile Stress ◽  
Fiber Organization ◽  
Fiber Contraction

Contractile stress generation by adherent cells is largely determined by the interplay of forces within their cytoskeleton. It is known that actin stress fibers, connected to focal adhesions, provide contractile stress generation, while microtubules and intermediate filaments provide cells compressive stiffness. Recent studies have shown the importance of the interplay between the stress fibers and the intermediate filament vimentin. Therefore, the effect of the interplay between the stress fibers and vimentin on stress generation was quantified in this study. We hypothesized that net stress generation comprises the stress fiber contraction combined with the vimentin resistance. We expected an increased net stress in vimentin knockout (VimKO) mouse embryonic fibroblasts (MEFs) compared to their wild-type (vimentin wild-type (VimWT)) counterparts, due to the decreased resistance against stress fiber contractility. To test this, the net stress generation by VimKO and VimWT MEFs was determined using the thin film method combined with sample-specific finite element modeling. Additionally, focal adhesion and stress fiber organization were examined via immunofluorescent staining. Net stress generation of VimKO MEFs was three-fold higher compared to VimWT MEFs. No differences in focal adhesion size or stress fiber organization and orientation were found between the two cell types. This suggests that the increased net stress generation in VimKO MEFs was caused by the absence of the resistance that vimentin provides against stress fiber contraction. Taken together, these data suggest that vimentin resists the stress fiber contractility, as hypothesized, thus indicating the importance of vimentin in regulating cellular stress generation by adherent cells.

scholarly journals Clathrin- and caveolin-1–independent endocytosis

2005 ◽  
Vol 168 (3) ◽  
pp. 477-488 ◽  
Author(s):  
Eva-Maria Damm ◽  
Lucas Pelkmans ◽  
Jürgen Kartenbeck ◽  
Anna Mezzacasa ◽  
Teymuras Kurzchalia ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Knockout Mouse ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Human Hepatoma ◽  
Wild Type ◽  
Embryonic Fibroblasts ◽  
Caveolin 1

Simian Virus 40 (SV40) has been shown to enter host cells by caveolar endocytosis followed by transport via caveosomes to the endoplasmic reticulum (ER). Using a caveolin-1 (cav-1)–deficient cell line (human hepatoma 7) and embryonic fibroblasts from a cav-1 knockout mouse, we found that in the absence of caveolae, but also in wild-type embryonic fibroblasts, the virus exploits an alternative, cav-1–independent pathway. Internalization was rapid (t1/2 = 20 min) and cholesterol and tyrosine kinase dependent but independent of clathrin, dynamin II, and ARF6. The viruses were internalized in small, tight-fitting vesicles and transported to membrane-bounded, pH-neutral organelles similar to caveosomes but devoid of cav-1 and -2. The viruses were next transferred by microtubule-dependent vesicular transport to the ER, a step that was required for infectivity. Our results revealed the existence of a virus-activated endocytic pathway from the plasma membrane to the ER that involves neither clathrin nor caveolae and that can be activated also in the presence of cav-1.

Differential expression of prohibitin and regulation of apoptosis in wild-type and COX-2 null mouse embryonic fibroblasts

2009 ◽  
Vol 53 (2) ◽  
pp. 157-159 ◽  
Author(s):  
Young-Hoon Kim ◽  
Hyangkyu Lee ◽  
Tae-Yoon Kim ◽  
Hyang-Ran Hwang ◽  
Sang Chul Lee
Keyword(s):  
Differential Expression ◽  
Null Mouse ◽  
Wild Type ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Cox 2

scholarly journals Caspase3-deficient cells require fibronectin for protection against autophagy-dependent death

2021 ◽  
Author(s):  
David B. Weir ◽  
Lawrence H. Boise
Keyword(s):  
Cell Death ◽  
Survival Advantage ◽  
Deficient Mouse ◽  
Wild Type ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Serum Withdrawal ◽  
Presence And Absence ◽  
Induced Apoptosis

ABSTRACTCaspases are required for execution of apoptosis. However, in their absence, signals that typically induce apoptosis can still result in cell death. Our laboratory previously demonstrated that Casp3-deficient mouse embryonic fibroblasts (MEFs) have increased fibronectin (FN) secretion, and an adhesion-dependent survival advantage compared to wild type (WT) MEFs. Here, we show that FN is required for survival of Casp3-deficient MEFs following serum withdrawal. Furthermore, when FN is silenced, serum withdrawal-induced death is caspase-independent. However, procaspase-7 is cleaved, suggesting that MOMP is taking place. Indeed, in the absence of FN, cytochrome c release is increased following serum withdrawal in Casp3-deficient MEFs. Yet death does not correspond to cytochrome c release in Casp3-deficient MEFs. This is true both in the presence and absence of FN. Additionally, caspase-independent death is inhibited by Bcl-XL overexpression. These findings suggest that Bcl-XL is not inhibiting death through regulation of Bax/Bak insertion into the mitochondria, but through a different mechanism. One such possibility is autophagy and induction of autophagy is associated with caspase-independent death in Casp3-deficient cells. Importantly, when ATG5 is ablated in Casp3-deficient cells, autophagy is blocked and death is largely inhibited. Taken together, our data indicate that Casp3-deficient cells incapable of undergoing canonical serum withdrawal-induced apoptosis, are protected from autophagy-dependent death by FN-mediated adhesion.

scholarly journals Loss of AMPKalpha1 Triggers Centrosome Amplification via PLK4 Upregulation in Mouse Embryonic Fibroblasts

2020 ◽  
Vol 21 (8) ◽  
pp. 2772
Author(s):  
Qiang Zhao ◽  
Kathleen A Coughlan ◽  
Ming-Hui Zou ◽  
Ping Song
Keyword(s):  
Molecular Mechanisms ◽  
Adenosine Monophosphate ◽  
Centrosome Amplification ◽  
Wild Type ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Cellular Energy ◽  
Chromosome Missegregation ◽  
Cell Mitosis ◽  
Metaphase Chromosome Spread

Recent evidence indicates that activation of adenosine monophosphate-activated protein kinase (AMPK), a highly conserved sensor and modulator of cellular energy and redox, regulates cell mitosis. However, the underlying molecular mechanisms for AMPKα subunit regulation of chromosome segregation remain poorly understood. This study aimed to ascertain if AMPKα1 deletion contributes to chromosome missegregation by elevating Polo-like kinase 4 (PLK4) expression. Centrosome proteins and aneuploidy were monitored in cultured mouse embryonic fibroblasts (MEFs) isolated from wild type (WT, C57BL/6J) or AMPKα1 homozygous deficient (AMPKα1−/−) mice by Western blotting and metaphase chromosome spread. Deletion of AMPKα1, the predominant AMPKα isoform in immortalized MEFs, led to centrosome amplification and chromosome missegregation, as well as the consequent aneuploidy (34–66%) and micronucleus. Furthermore, AMPKα1 null cells exhibited a significant induction of PLK4. Knockdown of nuclear factor kappa B2/p52 ameliorated the PLK4 elevation in AMPKα1-deleted MEFs. Finally, PLK4 inhibition by Centrinone reversed centrosome amplification of AMPKα1-deleted MEFs. Taken together, our results suggest that AMPKα1 plays a fundamental role in the maintenance of chromosomal integrity through the control of p52-mediated transcription of PLK4, a trigger of centriole biogenesis.

scholarly journals Differential Regulation of Cell Migration, Actin Stress Fiber Organization, and Cell Transformation by Functional Domains of Crk-associated Substrate

2002 ◽  
Vol 277 (30) ◽  
pp. 27265-27272 ◽  
Author(s):  
Jinhong Huang ◽  
Hiroko Hamasaki ◽  
Tetsuya Nakamoto ◽  
Hiroaki Honda ◽  
Hisamaru Hirai ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Transformation ◽  
Differential Regulation ◽  
Stress Fiber ◽  
Functional Domains ◽  
Actin Stress Fiber ◽  
Fiber Organization

scholarly journals SILAC based protein profiling data of MKK3 knockout mouse embryonic fibroblasts

Data in Brief ◽  
2016 ◽  
Vol 7 ◽  
pp. 418-422 ◽  
Author(s):  
Anup Srivastava ◽  
Amanda S. Shinn ◽  
TuKiet T. Lam ◽  
Patty J. Lee ◽  
Praveen Mannam
Keyword(s):  
Knockout Mouse ◽  
Protein Profiling ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts
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