scholarly journals The Human Papillomavirus E6 Oncogene Represses a Cell Adhesion Pathway and Disrupts Focal Adhesion through Degradation of TAp63β upon Transformation

2011 ◽  
Vol 7 (9) ◽  
pp. e1002256 ◽  
Author(s):  
Youcef Ben Khalifa ◽  
Sébastien Teissier ◽  
Meng-Kwang Marcus Tan ◽  
Quang Tien Phan ◽  
Mathieu Daynac ◽  
...  
2012 ◽  
Vol 35 (4) ◽  
pp. 267-284 ◽  
Author(s):  
F. Ouchani ◽  
J. Devy ◽  
A. Rusciani ◽  
J. J. Helesbeux ◽  
S. Salesse ◽  
...  

Background: Leukemic cell adhesion to proteins of the bone marrow microenvironment provides signals which control morphology, motility and cell survival. We described herein the ability of ethoxyfagaronine (etxfag), a soluble synthetic derivative of fagaronine, to prevent leukemic cell adhesion to fibronectin peptide (FN/V).Methods: Phosphorylation of fak and pyk2 were evaluated by immunoblotting. Labelled proteins were localized by confocal microscopy. PI 3-kinase activity was evaluated byin vitrokinase assay.Results: Subtoxic concentration of etxfag reduced L1210 cell adhesion to FN/V dependently of β1 integrin engagement. Etxfag impaired FN-dependent formation of β1 clustering without modifying β1 expression at the cell membrane. This was accompanied by a decrease of focal adhesion number, a diminution of fak and pyk2 phosphorylation at Tyr-576, Tyr-861 and Tyr-579, respectively leading to their dissociations from β1 integrin and inhibition of PI 3-kinase activity. Etxfag also induced a cell retraction accompanied by a redistribution of phosphorylated fak and pyk2 in the perinuclear region and lipid raft relocalization.Conclusion: Through its anti-adhesive potential, etxfag, combined with conventional cytotoxic drugs could be potentially designed as a new anti-leukemic drug.


2011 ◽  
Vol 29 (2) ◽  
pp. 107-112 ◽  
Author(s):  
Qi-Lian Liang ◽  
Guo-Qiang Chen ◽  
Zhou-Yu Li ◽  
Bi-Rong Wang

2014 ◽  
Vol 92 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Pradipta Banerjee ◽  
Alka Mehta ◽  
C. Shanthi

Collagen, a major structural protein of the ECM, is known for its high cell adherence capacity. This study was conducted to identify regions in collagen that harbour such bioactivity. Collagen from tendon was hydrolysed and the peptides fractionated using ion-exchange chromatography (IEC). Isolated peptide fractions were coated onto disposable dishes and screened for cell adherence and proliferative abilities. Active IEC fractions were further purified by chromatography, and two peptides, C2 and E1 with cell adhesion ability, were isolated. A cell adhesion assay done with different amounts of C2 coated onto disposable dishes revealed the maximum adhesion to be 94.6%, compared with 80% for collagen coated dishes and an optimum peptide coating density of 0.507 nmoles per cm2 area of the dish. Growth of cells on C2, collagen, and E1 revealed a similar pattern and a reduction in the doubling time compared with cells grown on uncoated dishes. C2 had a mass of 2.046 kDa with 22 residues, and sequence analysis revealed a higher percentage occurrence of hydrophilic residues compared with other regions in collagen. Docking studies revealed GDDGEA in C2 as the probable site of interaction with integrins α2β1 and α1β1, and stability studies proved C2 to be mostly protease-resistant.


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.


2002 ◽  
Vol 70 (7) ◽  
pp. 3804-3815 ◽  
Author(s):  
Giorgio Santoni ◽  
Roberta Lucciarini ◽  
Consuelo Amantini ◽  
Jordan Jacobelli ◽  
Elisabetta Spreghini ◽  
...  

ABSTRACT The signaling pathways triggered by adherence of Candida albicans to the host cells or extracellular matrix are poorly understood. We provide here evidence in C. albicans yeasts of a p105 focal adhesion kinase (Fak)-like protein (that we termed CaFak), antigenically related to the vertebrate p125Fak, and its involvement in integrin-like-mediated fungus adhesion to vitronectin (VN) and EA.hy 926 human endothelial cell line. Biochemical analysis with different anti-chicken Fak antibodies identified CaFak as a 105-kDa protein and immunofluorescence and cytofluorimetric analysis on permeabilized cells specifically stain C. albicans yeasts; moreover, confocal microscopy evidences CaFak as a cytosolic protein that colocalizes on the membrane with the integrin-like VN receptors upon yeast adhesion to VN. The protein tyrosine kinase (PTK) inhibitors genistein and herbimycin A strongly inhibited C. albicans yeast adhesion to VN and EA.hy 926 endothelial cells. Moreover, engagement of αvβ3 and αvβ5 integrin-like on C. albicans either by specific monoclonal antibodies or upon adhesion to VN or EA.hy 926 endothelial cells stimulates CaFak tyrosine phosphorylation that is blocked by PTK inhibitor. A role for CaFak in C. albicans yeast adhesion was also supported by the failure of VN to stimulate its tyrosine phosphorylation in a C. albicans mutant showing normal levels of CaFak and VNR-like integrins but displaying reduced adhesiveness to VN and EA.hy 926 endothelial cells. Our results suggest that C. albicans Fak-like protein is involved in the control of yeast cell adhesion to VN and endothelial cells.


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