Fibroblast Growth Factor Receptor-1 human

Provided as a transfected cell extract in SDS-PAGE loading buffer, ready to use in immunoblotting techniques.

Four distinct FGF receptors from four separate genes have been identified: FGFR-1 (flg), FGFR-2 (bek), FGFR-3, and FGFR-4. The prototypic FGF receptor has an extracellular region containing three immunoglobulin-like domains, transmembrane region containing a cytosolic tyrosine kinase domain activated by ligand binding. FGFR-1, FGFR-2, and FGFR-3 (but not FGFR-4) undergo further complexity by differential RNA splicing such that a total of 145 unique FGFR proteins may be produced.² Ligand binding specificity, signal transduction, and membrane attachment may be modified by alternative splicings. For example, one variant of FGFR-2 shows high affinity binding of aFGF and KFGF, but not bFGF, while another variant binds aFGF and bFGF but not KFGF. Some isoforms with truncated or absent tyrosine kinases may act as competitive antagonists. Although alternative splicing conveys a certain degree of specificity to the ligand-receptor reaction, there is considerable overlap in binding of the nine FGFs to the different FGFRs and their isoforms. Signal transduction occurs by ligand-induced receptor dimerization followed by tyrosine kinase cross-phosphorylation at particular sites of FGFR cytoplasmic domains. After the FGFR dimers are internalized by receptor-mediated endocytosis, these phosphotyrosine residues serve as highly selective binding sites for specific cytoplasmic SH2 molecules in the signal transduction pathway.⁴ FGF receptors are widely expressed during early development but become restricted at birth. Mutations in the extracellular domain of FGFR2 have been correlated to certain disorders of human skeletal development.⁷ A recurrent mutation of a single amino acid in the transmembrane domain of FGFR-3 is responsible for a type of skeletal maldevelopment.⁵ Overexpression of FGFR-4 or expression of variant forms of FGFR-1 or FGFR-2 have been linked to human breast carcinoma.²

Predominant doublet of ~110-120 kDa is detected by specific antibodies to FGFR-1.