β1 integrins are distributed in adhesion structures with fibronectin and caveolin and in coated pits

2003 ◽  
Vol 81 (5) ◽  
pp. 335-348 ◽  
Author(s):  
Nikhat D Boyd ◽  
Bosco M. C Chan ◽  
Nils O Petersen
Keyword(s):  
Extracellular Matrix ◽  
Protein Kinase ◽  
Matrix Protein ◽  
Adaptor Protein ◽  
Cytoskeletal Proteins ◽  
Matrix Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Matrix Protein ◽  
Coated Pits ◽  
Mitogen Activated Protein

Integrins are found in adhesion structures, which link the extracelullar matrix to cytoskeletal proteins. Here, we attempt to further define the distribution of β1 integrins in the context of their association with matrix proteins and other cell surface molecules relevant to the endocytic process. We find that β1 integrins colocalize with fibronectin in fibrillar adhesion structures. A fraction of caveolin is also organized along these adhesion structures. The extracellular matrix protein laminin is not concentrated in these structures. The α4β1 integrin exhibits a distinct distribution from other β1 integrins after cells have adhered for 1 h to extracellular matrix proteins but is localized in adhesion structures after 24 h of adhesion. There are differences between the fibronectin receptors: α5β1 integrins colocalize with adaptor protein-2 in coated pits, while α4β1 integrins do not. This parallels our earlier observation that of the two laminin receptors, α1β1 and α6β1, only αaβ1 integrins colocalize with adaptor protein-2 in coated pits. Calcium chelation or inhibition of mitogen-activated protein kinase kinase, protein kinase C, or src did not affect localization of α1β1 and α5β1 integrins in coated pits. Likewise, the integrity of coated-pit structures or adhesion structures is not required for integrin and adaptor protein-2 colocalization. This suggests a robust and possibly constitutive interaction between these integrins and coated pits.Key words: adhesion, endocytosis, extracellular matrix, microscopy, confocal, signalling.

scholarly journals Signaling Mechanisms in the Regulation of Renal Matrix Metabolism in Diabetes

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Meenalakshmi M. Mariappan
Keyword(s):  
Extracellular Matrix ◽  
Signaling Pathways ◽  
Matrix Protein ◽  
Structural Changes ◽  
Mammalian Target Of Rapamycin ◽  
Adverse Outcomes ◽  
Matrix Proteins ◽  
Extracellular Matrix Protein ◽  
Renal Hypertrophy ◽  
Matrix Metabolism

Renal hypertrophy and accumulation of extracellular matrix proteins are among cardinal manifestations of diabetic nephropathy. TGF beta system has been implicated in the pathogenesis of these manifestations. Among signaling pathways activated in the kidney in diabetes, mTOR- (mammalian target of rapamycin-)regulated pathways are pivotal in orchestrating high glucose-induced production of ECM proteins leading to functional and structural changes in the kidney culminating in adverse outcomes. Understanding signaling pathways that influence individual matrix protein expression could lead to the development of new interventional strategies. This paper will highlight some of the diverse components of the signaling network stimulated by hyperglycemia with an emphasis on extracellular matrix protein metabolism in the kidney in diabetes.

scholarly journals Specific Activation of Mitogen-activated Protein Kinase by Transforming Growth Factor-β Receptors in Lipid Rafts Is Required for Epithelial Cell Plasticity

2009 ◽  
Vol 20 (3) ◽  
pp. 1020-1029 ◽  
Author(s):  
Wei Zuo ◽  
Ye-Guang Chen
Keyword(s):  
Cell Migration ◽  
Growth Factor ◽  
Protein Kinase ◽  
Lipid Rafts ◽  
Transforming Growth Factor ◽  
Mitogen Activated Protein Kinase ◽  
Type I ◽  
Coated Pits ◽  
Mapk Activation ◽  
Mitogen Activated Protein

Transforming growth factor (TGF)-β regulates a spectrum of cellular events, including cell proliferation, differentiation, and migration. In addition to the canonical Smad pathway, TGF-β can also activate mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and small GTPases in a cell-specific manner. Here, we report that cholesterol depletion interfered with TGF-β–induced epithelial-mesenchymal transition (EMT) and cell migration. This interference is due to impaired activation of MAPK mediated by cholesterol-rich lipid rafts. Cholesterol-depleting agents specifically inhibited TGF-β–induced activation of extracellular signal-regulated kinase (ERK) and p38, but not Smad2/3 or Akt. Activation of ERK or p38 is required for both TGF-β–induced EMT and cell migration, whereas PI3K/Akt is necessary only for TGF-β–promoted cell migration but not for EMT. Although receptor heterocomplexes could be formed in both lipid raft and nonraft membrane compartments in response to TGF-β, receptor localization in lipid rafts, but not in clathrin-coated pits, is important for TGF-β–induced MAPK activation. Requirement of lipid rafts for MAPK activation was further confirmed by specific targeting of the intracellular domain of TGF-β type I receptor to different membrane locations. Together, our findings establish a novel link between cholesterol and EMT and cell migration, that is, cholesterol-rich lipid rafts are required for TGF-β–mediated MAPK activation, an event necessary for TGF-β–directed epithelial plasticity.

scholarly journals APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
Adaptor Protein ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Mapk Activation ◽  
P38 Mapk Pathway ◽  
Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

Abstract 474: ERK4-deficiency Potentiates the TAC-induced Increase in Collagen1-α 1 Messenger RNA in Mice

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Joelle Trepanier ◽  
Dharmendra D Dingar ◽  
Marc-Antoine Gillis ◽  
Pramod Sahadevan ◽  
Yan Fen Shi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Messenger Rna ◽  
Matrix Protein ◽  
Interstitial Fibrosis ◽  
Cardiac Fibroblasts ◽  
Primary Source ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Matrix Protein ◽  
Systolic And Diastolic Function

Cardiac hypertrophy, a common consequence of cardiopathologies such as hypertension and myocardial infarcts, involves formation of excessive interstitial fibrosis, which may impair cardiac function. Fibroblasts are the primary source of extracellular matrix protein. Extracellular-regulated kinase 4 (ERK4) is an atypical mitogen-activated protein kinase (MAPK). The regulation and role of ERK4 in the heart are currently unidentified and its only known target is MAP kinase-activated protein kinase 5 (MK5), a kinase involved in regulating fibroblast function. Following constriction of the transverse aorta (TAC), MK5 haplodeficient mice showed an attenuation of the TAC-induced increase in collagen 1-α 1 mRNA at 2-wk post-TAC and reduced hypertrophy 8-wk post-TAC. Further studies revealed MK5 immunoreactivity in cardiac fibroblasts but not myocytes. MK5 immunoprecipitates from whole heart contain ERK3 immunoreactivity, but not that of ERK4 or p38 MAPK. This study was to examine the role of ERK4 in myocardial structure, function, and remodeling 3-wk post-TAC. At 12 wk of age, echocardiographic imaging revealed systolic and diastolic function in male ERK4 -/- mice were similar to wild-type littermates (ERK4 +/+ ). Three weeks post-TAC, hypertrophy was similar in ERK4 +/+ and ERK4 -/- mice. Transcripts for BNP and βMHC increased to similar extent in TAC- ERK4 +/+ and TAC- ERK4 -/- mice. Two-way ANOVA indicated that ERK4 deficiency altered the effect of TAC on TGFβ 1 and collagen 1-α 1 transcript levels with each being higher in TAC-ERK4 -/- mice. Furthermore, MK5 immunoprecipitates from cardiac fibroblast lysates did not contain ERK4 immunoreactivity. Additional experiments revealed the presence of ERK4 immunoreactivity in myocytes but not fibroblasts. These results suggest 1) ERK4 may be involved in myocyte - fibroblast communication during myocardial remodeling and 2) in cardiac myocytes, ERK4 is part of a novel signaling cascade that does not involve MK5.

scholarly journals Fas-Mediated Apoptosis Is Regulated by the Extracellular Matrix Protein CCN1 (CYR61) In Vitro and In Vivo

2009 ◽  
Vol 29 (12) ◽  
pp. 3266-3279 ◽  
Author(s):  
Vladislava Juric ◽  
Chih-Chiun Chen ◽  
Lester F. Lau
Keyword(s):  
Extracellular Matrix ◽  
Wound Repair ◽  
Matrix Protein ◽  
Fas Ligand ◽  
Lymphoid Cells ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Matrix Protein ◽  
Intragastric Administration ◽  
Matricellular Proteins

ABSTRACT Although Fas ligand (FasL) is primarily expressed by lymphoid cells, its receptor Fas (CD95/Apo-1) is broadly expressed in numerous nonlymphoid tissues and can mediate apoptosis of parenchymal cells upon injury and infiltration of inflammatory cells. Here we show that CCN1 (CYR61) and CCN2 (CTGF), matricellular proteins upregulated at sites of inflammation and wound repair, synergize with FasL to induce apoptosis by elevating cellular levels of reactive oxygen species (ROS). CCN1 acts through engagement of integrin α6β1 and cell surface heparan sulfate proteoglycans, leading to ROS-dependent hyperactivation of p38 mitogen-activated protein kinase in the presence of FasL to enhance mitochondrial cytochrome c release. We show that CCN1 activates neutral sphingomyelinase, which functions as a key source of CCN1-induced ROS critical for synergism with FasL. Furthermore, Fas-dependent hepatic apoptosis induced by an agonistic monoclonal anti-Fas antibody or intragastric administration of alcohol is severely blunted in knock-in mice expressing an apoptosis-defective Ccn1 allele. These results demonstrate that CCN1 is a physiologic regulator of Fas-mediated apoptosis and that the extracellular matrix microenvironment can modulate Fas-dependent apoptosis through CCN1 expression.

The neuronal adaptor protein Fe65 is phosphorylated by mitogen-activated protein kinase (ERK1/2)

2003 ◽  
Vol 24 (4) ◽  
pp. 851-857 ◽  
Author(s):  
Claire L Standen ◽  
Michael S Perkinton ◽  
Helen L Byers ◽  
Sashi Kesavapany ◽  
Kwok-Fai Lau ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Adaptor Protein ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

Thromboxane stimulates synthesis of extracellular matrix proteins in vitro

1991 ◽  
Vol 261 (3) ◽  
pp. F488-F494 ◽  
Author(s):  
L. A. Bruggeman ◽  
E. A. Horigan ◽  
S. Horikoshi ◽  
P. E. Ray ◽  
P. E. Klotman
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
Mesangial Cells ◽  
Extracellular Matrix Proteins ◽  
Cellular Protein ◽  
Matrix Proteins ◽  
Extracellular Matrix Protein ◽  
Renal Diseases ◽  
Glomerular Mesangial Cells

The vasoconstrictor eicosanoid thromboxane plays an important role in the pathogenesis of several renal diseases. As an autacoid, its local release alters blood flow and induces platelet aggregation. We report a direct stimulatory effect of thromboxane on extracellular matrix protein production and gene expression in vitro. Treatment of two cell types, differentiated mouse teratocarcinoma cells (F9+) and human glomerular mesangial cells, with two different thromboxane analogues resulted in increased production of components of the extracellular matrix including fibronectin and the basement membrane proteins laminin and type IV collagen. These responses to thromboxane were not the result of a mitogenic effect of thromboxane nor the result of an increase in total cellular protein. The increased production of extracellular matrix proteins was, at least in part, due to an increase in the steady-state level of mRNA for these genes. Furthermore, the effect of thromboxane was markedly inhibited by cotreatment with a thromboxane-receptor antagonist. These results suggest a new potential role for thromboxane as a mediator of the sclerotic and fibrotic responses to injury.

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