FGFR1 (Basic fibroblast growth factor receptor 1) is a membrane receptor for basic fibroblast growth factor (FGF2) and for acidic fibroblast growth factor (FGF1). Binding of FGF and heparin leads to receptor dimerization and autophosphorylation at 7 tyrosine residues in the cytoplasmic tail. Phosphorylation of tyrosine 653 and 654 are important for catalytic activity while other sites may provide docking sites for downstream signaling components such as Crk and PLCgamma. FGFR1 also interacts with SHB, KLB, FGF23, GRB10. FGFR1 activation influences mitogenesis and differentiation of various cell types. Mutations and chromosomal aberrations are associated with various disorders including Pfeiffer Syndrome, idiopathic hypogonadotropic hypogonadism, Kallmann syndrome type 2, osteoglophonic dysplasia, non-syndromic trigonocephaly, stem cell leukemia lymphoma syndrome and stem cell myeloproliferative disorder.