scholarly journals Regulation of Macropinocytosis by p21-activated Kinase-1

2000 ◽  
Vol 11 (10) ◽  
pp. 3341-3352 ◽  
Author(s):  
Suranganie Dharmawardhane ◽  
Annette Schürmann ◽  
Mary Ann Sells ◽  
Jonathan Chernoff ◽  
Sandra L. Schmid ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Function ◽  
Normal Growth ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Membrane Ruffling ◽  
Vesicle Cycling ◽  
P21 Activated Kinase ◽  
Additional Stimulation ◽  
Pinocytic Vesicles

The process of macropinocytosis is an essential aspect of normal cell function, contributing to both growth and motile processes of cells. p21-activated kinases (PAKs) are targets for activated Rac and Cdc42 guanosine 5′-triphosphatases and have been shown to regulate the actin-myosin cytoskeleton. In fibroblasts PAK1 localizes to areas of membrane ruffling, as well as to amiloride-sensitive pinocytic vesicles. Expression of a PAK1 kinase autoinhibitory domain blocked both platelet-derived growth factor- and RacQ61L-stimulated uptake of 70-kDa dextran particles, whereas an inactive version of this domain did not, indicating that PAK kinase activity is required for normal growth factor-induced macropinocytosis. The mechanisms by which PAK modulate macropinocytosis were examined in NIH3T3 cell lines expressing various PAK1 constructs under the control of a tetracycline-responsive transactivator. Cells expressing PAK1 (H83,86L), a mutant that dramatically stimulates formation of dorsal membrane ruffles, exhibited increased macropinocytic uptake of 70-kDa dextran particles in the absence of additional stimulation. This effect was not antagonized by coexpression of dominant-negative Rac1-T17N. In the presence of platelet-derived growth factor, both PAK1 (H83,86L) and a highly kinase active PAK1 (T423E) mutant dramatically enhanced the uptake of 70-kDa dextran. Neither wild-type PAK1 nor vector controls exhibited enhanced macropinocytosis, nor did PAK1 (H83,86L) affect clathrin-dependent endocytic mechanisms. Active versions of PAK1 enhanced both growth factor-stimulated 70-kDa dextran uptake and efflux, suggesting that PAK1 activity modulated pinocytic vesicle cycling. These data indicate that PAK1 plays an important regulatory role in the process of macropinocytosis, perhaps related to the requirement for PAK in directed cell motility.

Platelet-derived growth factor inhibits basic fibroblast growth factor angiogenic properties in vitro and in vivo through its α receptor

Blood ◽  
2002 ◽  
Vol 99 (6) ◽  
pp. 2045-2053 ◽  
Author(s):  
Francesco De Marchis ◽  
Domenico Ribatti ◽  
Claudia Giampietri ◽  
Alessandro Lentini ◽  
Debora Faraone ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Cell Function ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Platelet Derived Growth Factor ◽  
Fibroblast Growth

Abstract Basic fibroblast growth factor (bFGF) and platelet-derived growth factor-BB (PDGF-BB) modulate vascular wall cell function in vitro and angiogenesis in vivo. The aim of the current study was to determine how bovine aorta endothelial cells (BAECs) respond to the simultaneous exposure to PDGF-BB and bFGF. It was found that bFGF-dependent BAEC migration, proliferation, and differentiation into tubelike structures on reconstituted extracellular matrix (Matrigel) were inhibited by PDGF-BB. The role played by PDGF receptor α (PDGF-Rα) was investigated by selective stimulation with PDGF-AA, by blocking PDGF-BB-binding to PDGF-Rα with neomycin, or by transfecting cells with dominant-negative forms of the receptors to selectively impair either PDGF-Rα or PDGF-Rβ function. In all cases, PDGF-Rα impairment abolished the inhibitory effect of PDGF-BB on bFGF-directed BAEC migration. In addition, PDGF-Rα phosphorylation was increased in the presence of bFGF and PDGF, as compared to PDGF alone, whereas mitogen-activated protein kinase phosphorylation was decreased in the presence of PDGF-BB and bFGF compared with bFGF alone. In vivo experiments showed that PDGF-BB and PDGF-AA inhibited bFGF-induced angiogenesis in vivo in the chick embryo chorioallantoic membrane assay and that PDGF-BB inhibited bFGF-induced angiogenesis in Matrigel plugs injected subcutaneously in CD1 mice. Taken together these results show that PDGF inhibits the angiogenic properties of bFGF in vitro and in vivo, likely through PDGF-Rα stimulation.

scholarly journals Diacylglycerol Kinase ζ Regulates Actin Cytoskeleton Reorganization through Dissociation of Rac1 from RhoGDI

2009 ◽  
Vol 20 (7) ◽  
pp. 2049-2059 ◽  
Author(s):  
Hanan Abramovici ◽  
Parmiss Mojtabaie ◽  
Robin J. Parks ◽  
Xiao-Ping Zhong ◽  
Gary A. Koretzky ◽  
...  
Keyword(s):  
Growth Factor ◽  
Platelet Derived Growth Factor ◽  
Actin Dynamics ◽  
Wild Type ◽  
Membrane Ruffling ◽  
Cytoskeleton Reorganization ◽  
Rac1 Gtpase ◽  
P21 Activated Kinase ◽  
Lamellipodia Formation ◽  
Dissociation Factor

Activation of Rac1 GTPase signaling is stimulated by phosphorylation and release of RhoGDI by the effector p21-activated kinase 1 (PAK1), but it is unclear what initiates this potential feed-forward mechanism for regulation of Rac activity. Phosphatidic acid (PA), which is produced from the lipid second messenger diacylglycerol (DAG) by the action of DAG kinases (DGKs), is known to activate PAK1. Here, we investigated whether PA produced by DGKζ initiates RhoGDI release and Rac1 activation. In DGKζ-deficient fibroblasts PAK1 phosphorylation and Rac1–RhoGDI dissociation were attenuated, leading to reduced Rac1 activation after platelet-derived growth factor stimulation. The cells were defective in Rac1-regulated behaviors, including lamellipodia formation, membrane ruffling, migration, and spreading. Wild-type DGKζ, but not a kinase-dead mutant, or addition of exogenous PA rescued Rac activation. DGKζ stably associated with PAK1 and RhoGDI, suggesting these proteins form a complex that functions as a Rac1-selective RhoGDI dissociation factor. These results define a pathway that links diacylglycerol, DGKζ, and PA to the activation of Rac1: the PA generated by DGKζ activates PAK1, which dissociates RhoGDI from Rac1 leading to changes in actin dynamics that facilitate the changes necessary for cell motility.

scholarly journals Loss of T-Cell Protein Tyrosine Phosphatase Induces Recycling of the Platelet-derived Growth Factor (PDGF) β-Receptor but Not the PDGF α-Receptor

2006 ◽  
Vol 17 (11) ◽  
pp. 4846-4855 ◽  
Author(s):  
Susann Karlsson ◽  
Katarzyna Kowanetz ◽  
Åsa Sandin ◽  
Camilla Persson ◽  
Arne Östman ◽  
...  
Keyword(s):  
T Cell ◽  
Growth Factor ◽  
Cell Surface ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Cell Protein ◽  
Protein Tyrosine ◽  
Β Receptor

We have previously shown that the T-cell protein tyrosine phosphatase (TC-PTP) dephosphorylates the platelet-derived growth factor (PDGF) β-receptor. Here, we show that the increased PDGF β-receptor phosphorylation in TC-PTP knockout (ko) mouse embryonic fibroblasts (MEFs) occurs primarily on the cell surface. The increased phosphorylation is accompanied by a TC-PTP–dependent, monensin-sensitive delay in clearance of cell surface PDGF β-receptors and delayed receptor degradation, suggesting PDGF β-receptor recycling. Recycled receptors could also be directly detected on the cell surface of TC-PTP ko MEFs. The effect of TC-PTP depletion was specific for the PDGF β-receptor, because PDGF α-receptor homodimers were cleared from the cell surface at the same rate in TC-PTP ko MEFs as in wild-type MEFs. Interestingly, PDGF αβ-receptor heterodimers were recycling. Analysis by confocal microscopy revealed that, in TC-PTP ko MEFs, activated PDGF β-receptors colocalized with Rab4a, a marker for rapid recycling. In accordance with this, transient expression of a dominant-negative Rab4a construct increased the rate of clearance of cell surface receptors on TC-PTP ko MEFs. Thus, loss of TC-PTP specifically redirects the PDGF β-receptor toward rapid recycling, which is the first evidence of differential trafficking of PDGF receptor family members.

p38 MAP kinase negatively regulates cyclin D1 expression in airway smooth muscle cells

2001 ◽  
Vol 280 (5) ◽  
pp. L955-L964 ◽  
Author(s):  
Kristen Page ◽  
Jing Li ◽  
Marc B. Hershenson
Keyword(s):  
Growth Factor ◽  
Map Kinase ◽  
Cyclin D1 ◽  
Growth Regulation ◽  
P38 Map Kinase ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Airway Smooth Muscle Cells ◽  
Erk Activation ◽  
Erk Phosphorylation

We have demonstrated that platelet-derived growth factor (PDGF) stimulates p38 mitogen-activated protein (MAP) kinase activation in bovine tracheal myocytes, suggesting that p38 is involved in growth regulation. We therefore examined whether p38 regulates expression of cyclin D1, a G1 cyclin required for cell cycle traversal. The chemical p38 inhibitors SB-202190 and SB-203580 each increased basal and PDGF-induced cyclin D1 promoter activity and protein abundance. Overexpression of a dominant negative allele of MAP kinase kinase-3 (MKK3), an upstream activator of p38α, had similar effects. Conversely, active MKK3 and MKK6, both of which increase p38α activity, each decreased transcription from the cyclin D1 promoter. Together, these data demonstrate that p38 negatively regulates cyclin D1 expression. We tested whether p38 regulates cyclin D1 expression via inhibition of extracellular signal-regulated kinase (ERK) activation. Chemical inhibitors of p38 induced modest ERK phosphorylation and activation. However, dominant negative MKK3 was insufficient to activate ERK, and active MKK3 and MKK6 did not attenuate platelet-derived growth factor-mediated ERK activation. These data are consistent with the notion that p38α negatively regulates cyclin D1 expression via an ERK-independent pathway.

scholarly journals Angiotensin II stimulates phosphorylation of an ectodomain-truncated platelet-derived growth factor receptor-β and its binding to class IA PI3K in vascular smooth muscle cells

2006 ◽  
Vol 397 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Ben-Bo Gao ◽  
Hans Hansen ◽  
Hong-Chi Chen ◽  
Edward P. Feener
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Growth Factor Receptor ◽  
At1 Receptor ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Ang Ii ◽  
Stimulation Of

PI3K (phosphoinositide 3-kinase) activity is involved in Ang (angiotensin) II-stimulated VSMC (vascular smooth muscle cell) growth and hypertrophy. In the present study, we demonstrate that the inhibition of PI3K in VSMCs by expression of a dominant-negative p85α mutant lacking the p110-binding domain (Δp85), or by treatment of cells with LY294002, inhibited Ang II-stimulated PAI-1 (plasminogen activator inhibitor-1) mRNA expression. Using a GST (glutathione S-transferase) fusion protein containing the p85 N-terminal SH2 (Src homology 2) domain as ‘bait’ followed by MS/MS (tandem MS), we identified a 70 kDa fragment of the p70 PDGFR-β (platelet-derived growth factor receptor-β) as a signalling adapter that is phosphorylated and recruits the p85 subunit of PI3K after Ang II stimulation of AT1 (Ang II subtype 1) receptors on VSMCs. This fragment of the PDGFR-β, which has a truncation of its extracellular domain, accounted for approx. 15% of the total PDGFR-β detected in VSMCs with an antibody against its cytoplasmic domain. Stimulation of VSMCs with Ang II increased tyrosine-phosphorylation of p70 PDGFR-β at Tyr751 and Tyr1021 and increased its binding to p85. PDGF also induced phosphorylation of p70 PDGFR-β, a response inhibited by the PDGF tyrosine kinase selective inhibitor, AG1296. By contrast, Ang II-induced phosphorylation of the 70 kDa receptor was not affected by AG1296. Ang II-stimulated phosphorylation of the p70 PDGFR-β was blocked by the AT1 receptor antagonist, candesartan (CV 11974) and was partially inhibited by PP2 {4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine}, an Src family kinase inhibitor. Our result suggests that the p70 PDGFR-β functions as an adapter that recruits PI3K to the membrane upon AT1 receptor stimulation.

scholarly journals An Essential Role of the Jak-2/STAT-3/Cytosolic Phospholipase A2Axis in Platelet-derived Growth Factor BB-induced Vascular Smooth Muscle Cell Motility

2004 ◽  
Vol 279 (44) ◽  
pp. 46122-46128 ◽  
Author(s):  
Indira Neeli ◽  
Zhimin Liu ◽  
Nagadhara Dronadula ◽  
Z. Alex Ma ◽  
Gadiparthi N. Rao
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Dominant Negative Mutant ◽  
Dependent Manner ◽  
Cytosolic Phospholipase ◽  
Negative Mutant

Platelet-derived growth factor-BB (PDGF-BB) is a potent motogen for vascular smooth muscle cells (VSMCs). To understand its motogenic signaling events, we have studied the role of the Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT) pathway and cytosolic phospholipase A2(cPLA2). PDGF-BB stimulated tyrosine phosphorylation of Jak-2 and STAT-3 in a time-dependent manner in VSMCs. In addition, AG490 and Jak-2KEpRK5, a selective pharmacological inhibitor and a dominant negative mutant, respectively, of Jak-2, attenuated PDGF-BB-induced STAT-3 tyrosine phosphorylation and its DNA binding and reporter gene activities. PDGF-BB induced VSMC motility in a dose-dependent manner with a maximum effect at 10 ng/ml. Dominant negative mutant-dependent suppression of Jak-2 and STAT-3 blocked PDGF-BB-induced VSMC motility. PDGF-BB induced the expression of cPLA2in a Jak-2/STAT-3-dependent manner, and pharmacological inhibitors of cPLA2prevented PDGFBB-induced VSMC motility. Furthermore, either exogenous addition of arachidonic acid or forced expression of cPLA2rescued PDGF-BB-induced VSMC motility from inhibition by blockade of Jak-2 and STAT-3 activation. Together, these results for the first time show that PDGF-BB-induced VSMC motility requires activation of the Jak-2/STAT-3/cPLA2signaling axis.

scholarly journals Postnatal Tendon Growth and Remodeling Requires Platelet-Derived Growth Factor Receptor Signaling

2017 ◽  
Author(s):  
Kristoffer B Sugg ◽  
James F Markworth ◽  
Nathaniel P Disser ◽  
Andrew M Rizzi ◽  
Jeffrey R Talarek ◽  
...  
Keyword(s):  
Growth Factor ◽  
Biological Activities ◽  
Growth Factor Receptor ◽  
Normal Growth ◽  
Platelet Derived Growth Factor ◽  
Growth And Remodeling ◽  
Fibroblast Migration ◽  
Membrane Type ◽  
And Migration

ABSTRACTPlatelet-derived growth factor receptor (PDGFR) signaling plays an important role in the fundamental biological activities of many cells that compose musculoskeletal tissues. However, little is known about the role of PDGFR signaling during tendon growth and remodeling in adult animals. Using the hindlimb synergist ablation model of tendon growth, our objectives were to determine the role of PDGFR signaling in the adaptation of tendons subjected to a mechanical growth stimulus, as well as to investigate the biological mechanisms behind this response. We demonstrate that both PDGFRs, PDGFRα and PDGFRβ, are expressed in tendon fibroblasts, and that the inhibition of PDGFR signaling suppresses the normal growth of tendon tissue in response to mechanical growth cues due to defects in fibroblast proliferation and migration. We also identify that membrane type-1 matrix metalloproteinase (MT1-MMP) as an essential proteinase for the migration of tendon fibroblasts through their extracellular matrix. Furthermore, we report that MT1-MMP translation is regulated by PI3K/Akt signaling, while ERK1/2 controls post-translational trafficking of MT1-MMP to the plasma membrane of tendon fibroblasts. Taken together, these findings demonstrate that PDGFR signaling is necessary for postnatal tendon growth and remodeling, and that MT1-MMP is a critical mediator of tendon fibroblast migration and a potential target for the treatment of tendon injuries and diseases.

The Effects of Platelet-Derived Growth Factor BB on Ovine Granulosa Cell Function.

2012 ◽  
Vol 87 (Suppl_1) ◽  
pp. 517-517
Author(s):  
Jennifer L. Juengel ◽  
Karen L. Reader ◽  
Michelle French ◽  
Stan Lun ◽  
Kenneth P. McNatty
Keyword(s):  
Growth Factor ◽  
Granulosa Cell ◽  
Cell Function ◽  
Platelet Derived Growth Factor
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