TGFβ-induced focal complex formation in epithelial cells is mediated by activated ERK and JNK MAP kinases and is independent of Smad4

2005 ◽  
Vol 386 (3) ◽  
Author(s):  
Yukiko Imamichi ◽  
Oliver Waidmann ◽  
Ramona Hein ◽  
Pinelopi Eleftheriou ◽  
Klaudia Giehl ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Complex Formation ◽  
Map Kinases ◽  
Focal Complex

scholarly journals Yersinia enterocolitica Adhesin A Induces Production of Interleukin-8 in Epithelial Cells

2004 ◽  
Vol 72 (12) ◽  
pp. 6780-6789 ◽  
Author(s):  
Yvonne Schmid ◽  
Guntram A. Grassl ◽  
Oliver T. Bühler ◽  
Mikael Skurnik ◽  
Ingo B. Autenrieth ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Yersinia Enterocolitica ◽  
Hela Cells ◽  
Map Kinases ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Interleukin 8 ◽  
Β1 Integrin ◽  
Β1 Integrins ◽  
Tissue Reactions

ABSTRACT The major invasive factor of Yersinia enterocolitica, the invasin (Inv) protein, induces proinflammatory host cell responses, including interleukin-8 (IL-8) secretion from human epithelial cells, by engagement of β1 integrins. The Inv-triggered β1 integrin signaling involves the small GTPase Rac; the activation of MAP kinases, such as p38, MEK1, and JNK; and the activation of the transcription factor NF-κB. In the present study, we demonstrate that Y. enterocolitica YadA, which is a major adhesin of Y. enterocolitica with pleiotropic virulence effects, induces IL-8 secretion in epithelial cells. The abilites of YadA and Inv to promote adhesion to and invasion of HeLa cells and to induce IL-8 production by the cells were investigated by expression of YadA and Inv in Escherichia coli. While YadA mediates efficacious adhesion to HeLa cells, it mediates marginal invasion compared with Inv. Both YadA and Inv trigger comparable levels of IL-8 production. Conformational changes of the YadA head domain by mutation of NSVAIG-S motifs, which abolish collagen binding, also abolish adhesion of Yersinia to HeLa cells and YadA-mediated IL-8 secretion. Furthermore, experiments in which blocking antibodies against β1 integrins were used demonstrate that β1 integrins are crucial for YadA-mediated IL-8 secretion. Inhibitor studies demonstrate the involvement of small GTPases and MAP kinases, such as p38, MEK1, and JNK, indicating that β1 integrin-dependent signaling mediated by Inv or YadA involves similar signaling pathways. These data present YadA, in addition to Inv, YopB, and Yersinia lipopolysaccharide, as a further inducer of proinflammatory molecules by which Y. enterocolitica might promote inflammatory tissue reactions.

scholarly journals Castration causes an increase in lysosomal size and upregulation of cathepsin D expression in principal cells along with increased secretion of procathepsin D and prosaposin oligomers in adult rat epididymis

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250454
Author(s):  
Lorena Carvelli ◽  
Andrea Carolina Aguilera ◽  
Leila Zyla ◽  
Laura Lucía Pereyra ◽  
Carlos R. Morales ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Complex Formation ◽  
Cathepsin D ◽  
Initial Segment ◽  
Lysosomal Enzymes ◽  
Sperm Maturation ◽  
Principal Cells ◽  
Adult Rat ◽  
Rat Epididymis ◽  
Lysosomal Proteins

In the epididymis, lysosomal proteins of the epithelial cells are normally targeted from the Golgi apparatus to lysosomes for degradation, although their secretion into the epididymal lumen has been documented and associated with sperm maturation. In this study, cathepsin D (CatD) and prosaposin (PSAP) were examined in adult epididymis of control, and 2-day castrated rats without (Ct) and with testosterone replacement (Ct+T) to evaluate their expression and regulation within epididymal epithelial cells. By light microscope-immunocytochemistry, a quantitative increase in size of lysosomes in principal cells of Ct animals was noted from the distal initial segment to the proximal cauda. Androgen replacement did not restore the size of lysosomes to control levels. Western blot analysis revealed a significant increase in CatD expression in the epididymis of Ct animals, which suggested an upregulation of its expression in principal cells; androgens restored levels of CatD to that of controls. In contrast, PSAP expression in Ct animals was not altered from controls. Additionally, an increase in procathepsin D levels was noted from samples of the epididymal fluid of Ct compared to control animals, accompanied by an increased complex formation with PSAP. Moreover, an increased oligomerization of prosaposin was observed in the epididymal lumen of Ct rats, with changes reverted to controls in Ct+T animals. Taken together these data suggest castration causes an increased uptake of substrates that are acted upon by CatD in lysosomes of principal cells and in the lumen by procathepsin D. These substrates may be derived from apoptotic cells noted in the lumen of proximal regions and possibly by degenerating sperm in distal regions of the epididymis of Ct animals. Exploring the mechanisms by which lysosomal enzymes are synthesized and secreted by the epididymis may help resolve some of the issues originating from epididymal dysfunctions with relevance to sperm maturation.

scholarly journals Internalization of prolactin receptor and prolactin in transfected cells does not involve nuclear translocation

1997 ◽  
Vol 110 (9) ◽  
pp. 1123-1132 ◽  
Author(s):  
M. Perrot-Applanat ◽  
O. Gualillo ◽  
H. Buteau ◽  
M. Edery ◽  
P.A. Kelly
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Cell Lines ◽  
Map Kinases ◽  
Nuclear Translocation ◽  
Short Form ◽  
Confocal Laser Microscopy ◽  
Confocal Laser ◽  
Laser Microscopy ◽  
Transfected Cells

Prolactin (PRL) interacts with a specific, well characterized plasma membrane receptor (PRLR) that is coupled to signal transduction pathways involving Jak2, Fyn, and MAP kinases, and signal transducers and activators of transcription (STAT). Although a few previous studies have indicated nuclear translocation of PRL in IL-2 stimulated T lymphocytes, PRL-dependent Nb2 lymphoma cell lines and 235–1 lactotrophs, the mechanisms of nuclear targeting remain unknown and conflicting results have been reported concerning the putative nuclear translocation of the PRLR. We therefore decided to investigate nuclear translocation of PRLR and PRL in various cell lines transfected with an expression plasmid encoding PRLR, using confocal laser microscopy. We have constructed various cDNAs of the long and short forms of the rat PRLR containing an oligonucleotide encoding a Flag epitope inserted either just before the N-terminal amino acid or in the C-terminal end of the mature receptor (named N-terminal or C-terminal Flag-tagged PRLR). The corresponding receptors function as the PRLR in transfected cells: they are expressed at the plasma membrane and in compartments of the secretory pathway, they bind PRL with normal affinity (Kd= 4x10(−10) M) and have the same capacity to stimulate the transcriptional activity of a milk protein (beta-casein) gene as wild-type PRLR. In addition, the tagged receptors are much more efficiently immunodetected using anti-Flag antibodies, as compared to anti-PRL antibodies (U5 or U6). Immunofluorescence combined with detailed confocal laser microscopy showed that addition of PRL (0 to 12 hours) to COS-7, CHO and NIH-3T3 transfected fibroblasts induces rapid internalization of the receptor (long form), without any translocation to the nucleus. Using PRL-R tagged both in the N-terminal or C-terminal regions of the mature receptor excludes the possibility of a cleaved fragment which could have been subsequently imported into the nucleus. An absence of nuclear translocation of PRLR was also observed in a 293 cell line stably expressing the receptor, and in physiological targets for PRL, i.e. in Nb2 lymphoma cells expressing the Nb2 form of the receptor or in BGME mammary gland epithelial cells upon overexpression of a Flag-tagged PRLR. Similarly, the short form of the PRLR was not detected in nuclei of transfected COS cells upon PRL treatment. Clearly, our results provide evidence that internalization of the plasma membrane PRLR does not lead to nuclear translocation of the receptor, or part of it, in most fibroblasts and epithelial cells at physiological concentrations of PRL. Also, in co-localization experiments, PRL was internalized without nuclear translocation. Activation of STATs transcription factors and MAP kinases, as well as translocation of these proteins to the nucleus following their phosphorylation, probably remains the intracellular mechanism coupling stimulation to nuclear events.

scholarly journals The assembly of integrin adhesion complexes requires both extracellular matrix and intracellular rho/rac GTPases.

1995 ◽  
Vol 131 (6) ◽  
pp. 1857-1865 ◽  
Author(s):  
N A Hotchin ◽  
A Hall
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Complex Formation ◽  
Map Kinase ◽  
Human Fibroblasts ◽  
Focal Adhesions ◽  
Small Gtpases ◽  
Wide Range ◽  
Focal Complex ◽  
Rho Family

Interaction of cells with extracellular matrix via integrin adhesion receptors plays an important role in a wide range of cellular: functions, for example cell growth, movement, and differentiation. Upon interaction with substrate, integrins cluster and associate with a variety of cytoplasmic proteins to form focal complexes and with the actin cytoskeleton. Although the intracellular signals induced by integrins are at present undefined, it is thought that they are mediated by proteins recruited to the focal complexes. It has been suggested, for example, that after recruitment to focal adhesions p125FAK can activate the ERK1/2 MAP kinase cascade. We have previously reported that members of the rho family of small GTPases can trigger the assembly of focal complexes when activated in cells. Using microinjection techniques, we have now examined the role of the extracellular matrix and of the two GTP-binding proteins, rac and rho, in the assembly of integrin complexes in both mouse and human fibroblasts. We find that the interaction of integrins with extracellular matrix alone is not sufficient to induce integrin clustering and focal complex formation. Similarly, activation of rho or rac by extracellular growth factors does not lead to focal complex formation in the absence of matrix. Focal complexes are only assembled in the presence of both matrix and functionally active members of the rho family. In agreement with this, the interaction of integrins with matrix in the absence of rho/rac activity is unable to activate the ERK1/2 kinases in Swiss 3T3 cells. In fact, ERK1/2 can be activated fully by growth factors in the absence of matrix and it seems unlikely, therefore, that the adhesion dependence of fibroblast growth is mediated through the ras/MAP kinase pathway. We conclude that extracellular matrix is not sufficient to trigger focal complex assembly and subsequent integrin-dependent signal transduction in the absence of functionally active members of the rho family of GTPases.

scholarly journals Integrin Activation and Focal Complex Formation in Cardiac Hypertrophy

2000 ◽  
Vol 275 (45) ◽  
pp. 35624-35630 ◽  
Author(s):  
Martin Laser ◽  
Christopher D. Willey ◽  
Wenjing Jiang ◽  
George Cooper ◽  
Donald R. Menick ◽  
...  
Keyword(s):  
Complex Formation ◽  
Cardiac Hypertrophy ◽  
Integrin Activation ◽  
Focal Complex

Role of mitochondria in aspirin-induced apoptosis in human gastric epithelial cells

2005 ◽  
Vol 289 (4) ◽  
pp. G731-G738 ◽  
Author(s):  
Maria J. Redlak ◽  
Jacinda J. Power ◽  
Thomas A. Miller
Keyword(s):  
Epithelial Cells ◽  
Complex Formation ◽  
Oxidative Phosphorylation ◽  
Caspase 8 ◽  
Mucosal Cell ◽  
Dependent Manner ◽  
Gastric Epithelial Cells ◽  
Caspase 9 ◽  
Mitochondrial Fractions ◽  
Induced Apoptosis

This study was undertaken to determine whether the Bcl-2 family proteins and Smac are regulators of aspirin-mediated apoptosis in a gastric mucosal cell line known as AGS cells. Cells were incubated with varying concentrations of acetylsalicylic acid (ASA; 2–40 mM), with or without preincubation of caspase inhibitors. Apoptosis was characterized by Hoechst staining and DNA-histone-associated complex formation. Antiapoptotic Bcl-2, proapoptotic Bax and Bid, Smac, and cytochrome- c oxidase (COX IV) were analyzed by Western blot analyses from cytosol and mitochondrial fractions. ASA downregulated Bcl-2 protein expression and induced Bax translocation into the mitochondria and cleavage of Bid. In contrast, expression of Smac was significantly decreased in mitochondrial fractions of ASA-treated cells. Bax and Bid involvement in apoptosis regulation was dependent on caspase activation, because caspase-8 inhibition suppressed Bax translocation and Bid processing. Caspase-9 inhibition prevented Smac release from mitochondria. Additionally, increased expression of the oxidative phosphorylation enzyme COX IV was observed in mitochondrial fractions exposed to ASA at concentrations >5 mM. Although caspase-8 inhibition had no effect on aspirin-induced apoptosis and DNA-histone complex formation, caspase-9 inhibition significantly decreased both of these events. We conclude that Bcl-2 protein family members and Smac regulate the apoptotic pathway in a caspase-dependent manner. Our results indicate also that mitochondrial integration and oxidative phosphorylation play a critical role in the pathogenesis of apoptosis in human gastric epithelial cells.

Soluble factors fromLactobacillus GGactivate MAPKs and induce cytoprotective heat shock proteins in intestinal epithelial cells

2006 ◽  
Vol 290 (4) ◽  
pp. C1018-C1030 ◽  
Author(s):  
Yun Tao ◽  
Kenneth A. Drabik ◽  
Tonya S. Waypa ◽  
Mark W. Musch ◽  
John C. Alverdy ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Heat Shock ◽  
Epithelial Cells ◽  
Map Kinases ◽  
Intestinal Epithelial Cells ◽  
Oxidant Stress ◽  
Signal Transduction Pathways ◽  
Clinical Effects ◽  
Dependent Manner ◽  
Intestinal Epithelial

Conditioned media from the probiotic Lactobacillus GG (LGG-CM) induce heat shock protein (Hsp) expression in intestinal epithelial cells. LGG-CM induces both Hsp25 and Hsp72 in a time- and concentration-dependent manner. These effects are mediated by a low-molecular-weight peptide that is acid and heat stable. DNA microarray experiments demonstrate that Hsp72 is one of the most highly upregulated genes in response to LGG-CM treatment. Real-time PCR and electrophoretic mobility shift assay confirm that regulation of Hsp induction is at least in part transcriptional in nature, involving heat shock factor-1. Although Hsps are not induced for hours after exposure, transient exposure to LGG-CM is sufficient to initiate the signal for Hsp induction, suggesting that signal transduction pathways may be involved. Experiments confirm that LGG-CM modulates the activity of certain signaling pathways in intestinal epithelial cells by activating MAP kinases. Inhibitors of p38 and JNK block the expression of Hsp72 normally induced by LGG-CM. Functional studies indicate that LGG-CM treatment of gut epithelial cells protects them from oxidant stress, perhaps by preserving cytoskeletal integrity. By inducing the expression of cytoprotective Hsps in gut epithelial cells, and by activating signal transduction pathways, the peptide product(s) secreted by LGG may contribute to the beneficial clinical effects attributed to this probiotic.

MEGAP impedes cell migration via regulating actin and microtubule dynamics and focal complex formation

2006 ◽  
Vol 312 (12) ◽  
pp. 2379-2393 ◽  
Author(s):  
Ying Yang ◽  
Marco Marcello ◽  
Volker Endris ◽  
Rainer Saffrich ◽  
Roger Fischer ◽  
...  
Keyword(s):  
Cell Migration ◽  
Complex Formation ◽  
Microtubule Dynamics ◽  
Focal Complex
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