scholarly journals FGF21 trafficking in intact human cells revealed by cryo-electron tomography with gold nanoparticles

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Maia Azubel ◽  
Stephen D Carter ◽  
Jennifer Weiszmann ◽  
Jun Zhang ◽  
Grant J Jensen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Growth Factor ◽  
Cell Surface ◽  
Fibroblast Growth Factor ◽  
Electron Tomography ◽  
Outer Cell ◽  
Multivesicular Bodies ◽  
Fibroblast Growth ◽  
Human Adipocytes ◽  
Cryo Electron Tomography

The fibroblast growth factor FGF21 was labeled with molecularly defined gold nanoparticles (AuNPs), applied to human adipocytes, and imaged by cryo-electron tomography (cryo-ET). Most AuNPs were in pairs about 80 Å apart, on the outer cell surface. Pairs of AuNPs were also abundant inside the cells in clathrin-coated vesicles and endosomes. AuNPs were present but no longer paired in multivesicular bodies. FGF21 could thus be tracked along the endocytotic pathway. The methods developed here to visualize signaling coupled to endocytosis can be applied to a wide variety of cargo and may be extended to studies of other intracellular transactions.

scholarly journals Cell surface fibroblast growth factor and epidermal growth factor receptors are permanently lost during skeletal muscle terminal differentiation in culture.

1988 ◽  
Vol 107 (2) ◽  
pp. 761-769 ◽  
Author(s):  
B B Olwin ◽  
S D Hauschka
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Surface ◽  
Fibroblast Growth Factor ◽  
Growth Factor Receptor ◽  
Growth Factor Receptors ◽  
Skeletal Muscle Differentiation ◽  
Fibroblast Growth ◽  
Epidermal Growth

One characteristic of skeletal muscle differentiation is the conversion of proliferating cells to a population that is irreversibly postmitotic. This developmental change can be induced in vitro by depriving the cultures of specific mitogens such as fibroblast growth factor (FGF). Analysis of cell surface FGF receptor (FGFR) in several adult mouse muscle cell lines and epidermal growth factor receptor (EGFR) in mouse MM14 cells reveals a correlation between receptor loss and the acquisition of a postmitotic phenotype. Quiescent MM14 cells, mitogen-depleted, differentiation-defective MM14 cells, and differentiated BC3H1 muscle cells (a line that fails to become postmitotic upon differentiation) retained their cell surface FGFR. These results indicate that FGFR loss is not associated with either reversible cessation of muscle cell proliferation or biochemical differentiation and thus, further support a correlation between receptor loss and acquisition of a postmitotic phenotype. Comparison of the kinetics for growth factor receptor loss and for commitment of MM14 cells to a postmitotic phenotype reveals that FGFR rises transiently from approximately 700 receptors/cell to a maximum of approximately 2,000 receptors/cell 12 h after FGF removal, when at the same time, greater than 95% of the cells are postmitotic. FGFR levels then decline to undetectable levels by 24 h after FGF removal. During the interval in which FGFR increases and then disappears there is no change in its affinity for FGF. The transient increase in growth factor receptors appears to be due to a decrease in ligand-mediated internalization because EGFR, which undergoes an immediate decline when cultures are deprived of FGF (Lim, R. W., and S. D. Hauschka. 1984. J. Cell Biol. 98:739-747), exhibits a similar transient rise when cultures are grown in media containing both EGF and FGF before switching the cells to media without these added factors. These results indicate that the loss of certain growth factor receptors is a specific phenotype acquired during skeletal muscle differentiation, but they do not resolve whether regulation of FGFR number is causal for initiation of the postmitotic phenotype. A general model is presented in the discussion.

scholarly journals Monovalent maleimide functionalization of gold nanoparticles via copper-free click chemistry

2014 ◽  
Vol 50 (86) ◽  
pp. 13157-13160 ◽  
Author(s):  
D. J. Nieves ◽  
N. S. Azmi ◽  
R. Xu ◽  
R. Lévy ◽  
E. A. Yates ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Growth Factor ◽  
Click Chemistry ◽  
Fibroblast Growth Factor ◽  
Michael Addition ◽  
The Self ◽  
Fibroblast Growth Factor 2 ◽  
Fibroblast Growth ◽  
Self Assembled Monolayer ◽  
Self Assembled

A single maleimide was installed onto the self-assembled monolayer of gold nanoparticles by copper-free click chemistry. Simple covalent biofunctionalisation is demonstrated by coupling fibroblast growth factor 2 and an oligosaccharide in a 1 : 1 stoichiometry by thiol-Michael addition.

scholarly journals Effect of transforming growth factor-β1 and basic fibroblast growth factor on the expression of cell surface proteoglycans in human lung fibroblasts. Enhanced glycanation and fibronectin-binding of CD44 proteoglycan, and down-regulation of glypican

1995 ◽  
Vol 310 (1) ◽  
pp. 73-81 ◽  
Author(s):  
M Romarís ◽  
A Bassols ◽  
G David
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Fibroblast Growth Factor ◽  
Transforming Growth Factor ◽  
Human Lung ◽  
Core Protein ◽  
Lung Fibroblasts ◽  
Fibroblast Growth ◽  
Tgf Beta ◽  
Human Lung Fibroblasts

We have tested the effects of transforming growth factor-beta 1 (TGF-beta 1), basic fibroblast growth factor (bFGF) and TGF-beta 1 + bFGF on the expression of the cell surface proteoglycans (CD44, syndecans and glypican) in cultures of human lung fibroblasts (HLF). Cell surface proteoglycan expression was monitored by quantitative immunoprecipitation from metabolically labelled cells. Western and Northern blotting and evaluation of the glycanation of the proteoglycans. Stimulation of the cells with TGF-beta 1 increased the length of the chondroitin sulphate (CS) chains on CD44 (approximately 1.6-fold). bFGF, administered solely, also increased the length of the CS chains on CD44 (approximately 1.4-fold), whereas the combination of TGF-beta 1 + bFGF nearly doubled both the length and the number of the CS chains on CD44. None of these treatments lead to changes in CD44 message or core-protein expression. This enhanced glycanation of CD44 after the TGF-beta 1, bFGF and combined treatments correlated with a 2-fold increase in the affinity of the proteoglycan for fibronectin but had no influence on the binding to type I collagen. TGF-beta 1, alone or in combination with bFGF, also stimulated the CS content of syndecan-1, but none of the other syndecans was significantly affected by any of the factors or combinations tested. The expression of glypican however was significantly decreased (nearly halved) by the combination of TGF-beta 1 + bFGF, less so by TGF-beta 1 and not at all by bFGF. This decrease occurred both at the level of the message and of the core protein. These data demonstrate specific and differential effects of TGF-beta 1 and bFGF on the structure, expression and interactions of the cell surface proteoglycans of HLF.

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