Receptor for basic fibroblast growth factor. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Transcripts accumulate when morphogenesis begins with mesenchyme cell ingression and gastrulation. Accumulation in all cell types of the embryo, although hybridization shows that they are somewhat enriched in cells of oral ectoderm and endoderm. Isoform 2 transcript is enriched in endomesoderm. Belongs to the protein kinase superfamily. Tyr protein kinase family. Fibroblast growth factor receptor subfamily.