scholarly journals Endogenous basic fibroblast growth factor isoforms involved in different intracellular protein complexes

1997 ◽  
Vol 326 (1) ◽  
pp. 259-264 ◽  
Author(s):  
Véronique PATRY ◽  
Béatrix BUGLER ◽  
Arlette MARET ◽  
Michel POTIER ◽  
Hervé PRATS
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Cho Cells ◽  
Protein Complexes ◽  
Biological Activities ◽  
Molecular Complexes ◽  
Fibroblast Growth ◽  
Initiation Of Translation

Four forms of basic fibroblast growth factor (bFGF or FGF-2) result from an alternative initiation of translation involving one AUG (155-amino acid form) and three CUGs (210-, 201- and 196-amino acid forms). These different forms of bFGF show different intracellular biological activities. To identify their intracellular targets, the 210- and 155-amino acid forms of bFGF were independently transfected into CHO cells and their correct subcellular localizations were verified, the 155-amino acid bFGF form being essentially cytoplasmic whereas the 210-amino acid protein was nuclear. The radiation fragmentation method was used to determine the target size of the different bFGF isoforms in the transfected CHO cells and to show that the 210- and 155-amino acids bFGF isoforms were included in protein complexes of 320 and 130 kDa respectively. Similar results were obtained using the SK-Hep1 cell line, which naturally expressed all forms of bFGF. Co-immunoprecipitation assays using different chimaeric bFGF–chloramphenicol acetyltransferase proteins showed that different cellular proteins are associated with different parts of the bFGF molecule. We conclude that bFGF isoforms are involved in different molecular complexes in the cytosol and nucleus, which would reflect different functions for these proteins.

scholarly journals Basic fibroblast growth factor does not prevent heparan sulphate proteoglycan catabolism in intact cells, but it alters the distribution of the glycosaminoglycan degradation products

1999 ◽  
Vol 337 (3) ◽  
pp. 471-481 ◽  
Author(s):  
Sarka TUMOVA ◽  
Brian A. HATCH ◽  
Douglas J. LAW ◽  
Karen J. BAME
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Cho Cells ◽  
Degradation Products ◽  
Biological Activities ◽  
Heparan Sulphate ◽  
Primary Role ◽  
Fibroblast Growth ◽  
Intact Cells

Heparan sulphate proteoglycans on cell surfaces have been shown to mediate the degradation or recycling of several ligands. Since the interaction with ligand may affect proteoglycan catabolism once the complex is internalized, this could alter the cellular pool of heparan sulphate chains, with possible consequences for heparan sulphate-mediated cellular processes. We have recently demonstrated that the specific binding of basic fibroblast growth factor (bFGF) to heparan sulphate chains prevents the glycosaminoglycan from being degraded by partially purified heparanases from Chinese hamster ovary (CHO) cells [Tumova and Bame (1997) J. Biol. Chem. 272, 9078–9085]. The present study examines the effect of bFGF on heparan sulphate catabolism in intact cells. The distribution and size of the heparan sulphate degradation products in CHO cells was analysed in the presence and absence of bFGF using pulse–chase protocols. Although heparan sulphate molecules and bFGF are internalized through the same pathway, even relatively high concentrations of the growth factor do not have any inhibitory effects on glycosaminoglycan degradation. However, the interaction with the growth factor alters the distribution of heparan sulphate-degradation products, presumably by preventing secretion of the short heparanase-derived species. Our findings show that most of the free and bFGF-bound heparan sulphate chains are destined for lysosomes, which would be consistent with a recent hypothesis that the primary role of proteoglycan-mediated internalization of the growth factor is to remove bFGF from its site of action at the cell surface. However, in the presence of bFGF, a fraction of intracellular, heparanase-degraded heparan sulphate chains is delivered to the nucleus, suggesting that the glycosaminoglycan accompanies the growth factor to the organelle. It may be important for bFGF activity that the growth factor is protected from proteolytic degradation by its interaction with heparan sulphate. This work demonstrates that the internalization of a ligand along with the proteoglycan can affect the sorting of heparan sulphate-degradation products in endosomes, and the ultimate destination of the short glycosaminoglycan. It also provides evidence that formation of heparan sulphate–ligand complexes may regulate the recycling and degradation of both ligands and heparan sulphate chains and, consequently, affect their biological activities.

cis-acting elements involved in the alternative translation initiation process of human basic fibroblast growth factor mRNA

1992 ◽  
Vol 12 (10) ◽  
pp. 4796-4805
Author(s):  
A C Prats ◽  
S Vagner ◽  
H Prats ◽  
F Amalric
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Untranslated Region ◽  
Specific Effect ◽  
Regulatory Elements ◽  
Fibroblast Growth ◽  
Cis Acting ◽  
Initiation Of Translation ◽  
Alternative Translation

Four forms of basic fibroblast growth factor (bFGF) are synthesized from the same mRNA, resulting from alternative initiations of translation at three CUG start codons and one AUG start codon. The CUG- and AUG-initiated forms have distinct intracellular localizations and can modify cell phenotypes differently, indicating that control of the alternative expression of the different forms of bFGF has an important impact on the cell. In this study, we investigated the roles of the mRNA 5' untranslated region and the alternatively translated region located between the CUG and AUG codons in the regulation of alternative translation of the different forms of bFGF. Deletions and site-directed mutagenesis were carried out in bFGF mRNA leader, and translation was studied in vitro and in vivo. The results enabled us to identify five cis-acting RNA elements (two in the 5' untranslated region and three in the alternatively translated region) involved in the regulation of either global or alternative initiation of translation. Each of these elements had a specific effect on the level of synthesis of the different forms of bFGF. Furthermore, we showed that the 5' untranslated region regulatory elements had different effects on bFGF translation, depending on the translation system used. These results suggest that bFGF translation is modulated by cis-acting elements corresponding to secondary or tertiary RNA structures, which could be the targets of cell-specific trans-acting factors.

Structural features in heparin which modulate specific biological activities mediated by basic fibroblast growth factor

Glycobiology ◽  
1994 ◽  
Vol 4 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Masayuki Ishihara ◽  
Patrick N. Shaklee ◽  
Zicheng Yang ◽  
Wesheng Liang ◽  
Zheng Wei ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Biological Activities ◽  
Structural Features ◽  
Fibroblast Growth

Purification and characterization of the 210-amino acid recombinant basic fibroblast growth factor form (FGF-2)

FEBS Letters ◽  
1994 ◽  
Vol 349 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Véronique Patry ◽  
Béatrix Bugler ◽  
François Amalric ◽  
Jean-Claude Promé ◽  
Hervé Prats
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Fibroblast Growth ◽  
Purification And Characterization ◽  
Factor Form
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