Fibroblast growth factor receptor 3 lacking the Ig IIIb and transmembrane domains secreted from human squamous cell carcinoma DJM-1 binds to FGFs.
The fibroblast growth factor receptors (FGFRs) are a family of transmembrane tyrosine kinases that play a key role in cell growth and tumorigenesis in response to FGFs. FGFR complexity is increased by the existence of additional isoforms generated by alternative mRNA splicing. We identified that the transcript FGFR3DeltaTM, an alternatively spliced isoform of FGFR3 lacking exons encoding the C-terminal half of Ig III (IIIb) and transmembrane domains, is expressed in the human squamous carcinoma cell line DJM-1. To determine whether FGFR3DeltaTM has the potential to be secreted, we analyzed the protein expression in CHOK1 cells transfected with FGFR3DeltaTM cDNA and DJM-1 cells. Western blot analysis revealed that FGFR3DeltaTM protein was secreted, N-glycosylated, and dimerized by an intermolecular disulfide bond. Cross-linking experiments showed that FGF1 and FGF2 were able to bind to FGFR3DeltaTM, suggesting that the loss of the Ig IIIb domain may confer upon FGFR3DeltaTM the ability to bind to FGF2.
Terada
M
M
Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan.
Shimizu
A
A
Sato
N
N
Miyakaze
S I
SI
Katayama
H
H
Kurokawa-Seo
M
M
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D016466:CHO Cells; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides; D005091:Exons; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006031:Glycosylation; D006493:Heparin / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases; D012313:RNA / Q000378:metabolism; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012685:Sepharose / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured
D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D004220:Disulfides; D020033:Protein Isoforms; D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins; D012313:RNA; D006493:Heparin; D012685:Sepharose; C496365:FGFR3 protein, human; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3; D006026:Glycoside Hydrolases