scholarly journals Fibroblast growth factor receptor levels decrease during chick embryogenesis.

1990 ◽  
Vol 110 (2) ◽  
pp. 503-509 ◽  
Author(s):  
B B Olwin ◽  
S D Hauschka
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Binding Sites ◽  
Specific Binding ◽  
Growth Factor Receptor ◽  
Receptor Protein ◽  
Chick Embryos ◽  
Fibroblast Growth ◽  
Fgf Receptor

Two putative receptors for fibroblast growth factor (FGF) of approximately 150 and 200 kD were identified in membrane preparations from chick embryos. Specific binding (femtomoles/milligram) of 125I-aFGF to whole chick embryonic membranes was relatively constant from day 2 to 7, then decreased fivefold between days 7 and 13. Day-19 chick embryos retained 125I-aFGF binding at low levels to brain, eye, and liver tissues but not to skeletal muscle or cardiac tissues. The 200-kD FGF receptor began to decline between day 4.5 and 7 and was barely detectable by day 9, whereas the 150-kD FGF receptor began to decline by day 7 but was still detectable in day-9 embryonic membranes. It is not known whether the two FGF-binding proteins represent altered forms of one polypeptide, but it is clear that their levels undergo differential changes during development. Because endogenous chick FGF may remain bound to FGF receptor in membrane preparations, membranes were treated with acidic (pH 4.0) buffers to release bound FGF; such treatment did not affect 125I-aFGF binding and moderately increased the number of binding sites in day-7 and -19 embryos. Consequently, the observed loss of high affinity 125I-aFGF binding sites and FGF-binding polypeptides most likely represents a loss of FGF receptor protein. These experiments provide in vivo evidence to support the hypothesis that regulation of FGF receptor levels may function as a mechanism for controlling FGF-dependent processes during embryonic development.

scholarly journals Fibroblast Growth Factor Receptor-Mediated Rescue of x-Ephrin B1-Induced Cell Dissociation in XenopusEmbryos

2000 ◽  
Vol 20 (2) ◽  
pp. 724-734 ◽  
Author(s):  
Lisa D. Chong ◽  
Eui Kyun Park ◽  
Erin Latimer ◽  
Robert Friesel ◽  
Ira O. Daar
Keyword(s):  
Cell Adhesion ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Fibroblast Growth ◽  
Fgf Receptor ◽  
Cell Adhesion And Migration ◽  
Membrane Bound ◽  
And Migration

ABSTRACT The Eph family of receptor tyrosine kinases and their membrane-bound ligands, the ephrins, have been implicated in regulating cell adhesion and migration during development by mediating cell-to-cell signaling events. Genetic evidence suggests that ephrins may transduce signals and become tyrosine phosphorylated during embryogenesis. However, the induction and functional significance of ephrin phosphorylation is not yet clear. Here, we report that when we used ectopically expressed proteins, we found that an activated fibroblast growth factor (FGF) receptor associated with and induced the phosphorylation of ephrin B1 on tyrosine. Moreover, this phosphorylation reduced the ability of overexpressed ephrin B1 to reduce cell adhesion. In addition, we identified a region in the cytoplasmic tail of ephrin B1 that is critical for interaction with the FGF receptor; we also report FGF-induced phosphorylation of ephrins in a neural tissue. This is the first demonstration of communication between the FGF receptor family and the Eph ligand family and implicates cross talk between these two cell surface molecules in regulating cell adhesion.

The fibroblast growth factor receptor, FGFR3, forms gradients of intact and degraded protein across the growth plate of developing bovine ribs

2002 ◽  
Vol 361 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Sujata G. PANDIT ◽  
Prasanthi GOVINDRAJ ◽  
Joachim SASSE ◽  
Peter J. NEAME ◽  
John R. HASSELL
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Growth Plate ◽  
Point Mutations ◽  
Growth Factor Receptor ◽  
Fibroblast Growth ◽  
Fgf Receptor ◽  
Hypertrophic Zone ◽  
The Matrix ◽  
Maximum Expression

Point mutations in the human fibroblast growth factor (FGF) receptor 3 gene (Fgfr3) produce a constitutively active receptor, which disrupts chondrocyte differentiation in the growth plate and results in skeletal dysplasias with severe shortening of the limbs. Alternative splicing of the Fgfr3 transcript gives rise to two isoforms, IIIc and IIIb, which vary in their specificity for FGF ligands. We examined the expression of these FGFR3 isoforms in the bovine fetal rib growth plate to determine whether levels of FGFR3 expression are zone-related. Transcripts for both Fgfr3 isoforms are expressed in rib growth plate, with maximum expression in the hypertrophic region and the least expression in the reserve zone. Fgfr3 IIIc is the predominant isoform in the growth plate. Western-blot analysis revealed the presence of full-length FGFR3 (135kDa) for both isoforms in the reserve zone, a major 98kDa fragment in all zones and smaller fragments primarily in the hypertrophic zone. Immunostaining localized FGFR3 to the pericellular region of reserve chondrocytes and to the extracellular matrix in the hypertrophic zone. These results suggest that the transmembrane form of FGFR3 increasingly undergoes proteolytic cleavage towards the hypertrophic zone to produce an extracellular-domain fragment of FGFR3, which is present in large amounts in the matrix of hypertrophic cells. These findings suggest a proteolytic regulatory mechanism for FGFR3, whereby Fgfr3 fragments could control availability of FGF for the intact receptor, and by which proteolysis could inactivate the receptor.

scholarly journals FGFRL1 Promotes Ovarian Cancer Progression by Crosstalk with Hedgehog Signaling

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Haiyan Tai ◽  
Zhiyong Wu ◽  
Su’an Sun ◽  
Zhigang Zhang ◽  
Congjian Xu
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor Receptor ◽  
Growth Factor Receptor ◽  
Fibroblast Growth ◽  
Hh Signaling ◽  
And Migration

Fibroblast growth factor receptor-like-1 (FGFRL1) has been identified as the fifth fibroblast growth factor receptor. So far, little is known about its biological functions, particularly in cancer development. Here, for the first time, we demonstrated the roles of FGFRL1 in ovarian carcinoma (OC). An array and existing databases were used to investigate the expression profile of FGFRL1 and the relationship between FGFRL1 expression and clinicopathological parameters. FGFRL1 was significantly upregulated in OC patients, and high FGFRL1 expression was correlated with poor prognosis. In vitro cell proliferation, apoptosis and migration assays, and in vivo subcutaneous xenograft tumor models were used to determine the role of FGFRL1. Loss of function of FGFRL1 significantly influenced cell proliferation, apoptosis, and migration of OC cells in vitro and tumor growth in vivo. Chromatin immunoprecipitation PCR analysis and microarray hybridization were performed to uncover the mechanism. FGFRL1 expression could be induced by hypoxia through hypoxia-inducible factor 1α, which directly binds to the promoter elements of FGFRL1. FGFRL1 promoted tumor progression by crosstalk with Hedgehog (Hh) signaling. Taken together, FGFRL1 is a potential predictor and plays an important role in tumor growth and Hh signaling which could serve as potential therapeutic targets for the treatment of OC.

Spatially restricted expression of fibroblast growth factor receptor-2 during Xenopus development

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1051-1058 ◽  
Author(s):  
R. Friesel ◽  
S.A. Brown
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor Receptor ◽  
Sequence Similarity ◽  
Growth Factor Receptor ◽  
Otic Vesicle ◽  
Amino Acid Sequence Similarity ◽  
Fibroblast Growth ◽  
Fgf Receptor ◽  
Mesoderm Inducing Factors

The fibroblast growth factors (FGFs) play a role in Xenopus laevis embryonic development, particularly in the induction of ventral-type mesoderm. We have isolated a full-length cDNA from Xenopus that we have designated Xenopus fibroblast growth factor receptor-2 (XFGFR-2), with significant amino acid sequence similarity to the previously described bek gene (FGFR-2). We expressed the XFGFR-2 cDNA in COS1 cells and showed that it functions as an FGF receptor by binding radiolabeled FGF-2. RNA gel blot analysis demonstrates that unlike Xenopus fibroblast growth factor receptor-1 (XFGFR-1), XFGFR-2 mRNA expression begins during gastrulation and continues through early tadpole stages. Whole-mount in situ hybridization demonstrates that XFGFR-2 mRNA is localized to the anterior neural plate in early neurula stage embryos. Later in development, XFGFR-2 expression is found in the eye anlagen, midbrain-hindbrain boundary and the otic vesicle. In addition, XFGFR-2 transcripts are expressed in animal caps in a manner that is independent of mesoderm-inducing factors. These results indicate that XFGFR-2 may have a role in development that is distinct from that of XFGFR-1.

scholarly journals Spred2 interaction with the late endosomal protein NBR1 down-regulates fibroblast growth factor receptor signaling

2009 ◽  
Vol 187 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Faraz K. Mardakheh ◽  
Mona Yekezare ◽  
Laura M. Machesky ◽  
John K. Heath
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Growth Factor Receptor ◽  
Degradation Pathway ◽  
Growth Factor Signaling ◽  
Fibroblast Growth ◽  
Fgf Signaling ◽  
Critical Function ◽  
Underlying Mechanisms

The potential for modulation of growth factor signaling by endocytic trafficking of receptors is well recognized, but the underlying mechanisms are poorly understood. We examined the regulation of fibroblast growth factor (FGF) signaling by Sprouty related with EVH1 (Ena/VASP homology 1) domain (Spred), a family of signaling inhibitors with proposed tumor-suppressive functions. The inhibitory activity of Spreds has been linked to their N-terminal EVH1 domain, but the molecular mechanism is unknown. In this study, we identify a novel late endosomal protein that directly binds to the EVH1 domain of Spred2. Neighbor of BRCA1 (NBR1) is a highly conserved multidomain protein that interacts and colocalizes with Spred2 in vivo. Attenuation of FGF signaling by Spred2 is dependent on the interaction with NBR1 and is achieved by redirecting the trafficking of activated receptors to the lysosomal degradation pathway. Our findings suggest a critical function for NBR1 in the regulation of receptor trafficking and provide a mechanism for down-regulation of signaling by Spred2 via NBR1.

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