title: FGFR3IIIS: a novel soluble FGFR3 spliced variant that modulates growth is frequently expressed in tumour cells.
abstract: Fibroblast growth factor receptor 3 (FGFR3) is one of four high-affinity tyrosine kinase receptors for the FGF family of ligands, frequently associated with growth arrest and induction of differentiation. The extracellular immunoglobulin (IgG)-like domains II and III are responsible for ligand binding; alternative usage of exons IIIb and IIIc of the Ig-like domain III determining the ligand-binding specificity of the receptor. By reverse transcriptase polymerase chain reaction (RT-PCR) a novel FGFR3IIIc variant FGFR3IIIS, expressed in a high proportion of tumours and tumour cell lines but rarely in normal tissues, has been identified. Unlike recently described nonsense transcripts of FGFR3, the coding region of FGFR3IIIS remains in-frame producing a novel protein. The protein product is coexpressed with FGFR3IIIc in the membrane and soluble cell fractions; expression in the soluble fraction is decreased after exposure to bFGF but not aFGF. Knockout of FGFR3IIIS using antisense has a growth-inhibitory effect in vitro, suggesting a dominant-negative function for FGFR3IIIS inhibiting FGFR3-induced growth arrest. In summary, alternative splicing of the FGFR3 Ig-domain III represents a mechanism for the generation of receptor diversity. FGFR3IIIS may regulate FGF and FGFR trafficking and function, possibly contributing to the development of a malignant phenotype.
authors.affiliation: Candlelighter's Children's Cancer Research Laboratory, Cancer Research UK Clinical Centre, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK.
authors.forename: L-M
authors.initials: LM
authors.lastname: Sturla
authors.forename: A E
authors.initials: AE
authors.lastname: Merrick
authors.forename: S A
authors.initials: SA
authors.lastname: Burchill
mesh_terms: D017398:Alternative Splicing; D015139:Blotting, Southern; D002455:Cell Division / Q000187:drug effects; D017931:DNA Primers; D005091:Exons / Q000235:genetics; D016220:Fibroblast Growth Factor 1 / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D020033:Protein Isoforms; D011505:Protein-Tyrosine Kinases; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics* / Q000378:metabolism; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D007136:Immunoglobulins; D016376:Oligonucleotides, Antisense; D020033:Protein Isoforms; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; C496365:FGFR3 protein, human; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3