Recombinant human Flt4 protein (ab126923)

Protein kinases are enzymes that transfer a phosphate group from a phosphate donor, generally the g phosphate of ATP, onto an acceptor amino acid in a substrate protein. By this basic mechanism, protein kinases mediate most of the signal transduction in eukaryotic cells, regulating cellular metabolism, transcription, cell cycle progression, cytoskeletal rearrangement and cell movement, apoptosis, and differentiation. With more than 500 gene products, the protein kinase family is one of the largest families of proteins in eukaryotes. The family has been classified in 8 major groups based on sequence comparison of their tyrosine (PTK) or serine/threonine (STK) kinase catalytic domains. The tyrosine kinase (TK) group is mainly involved in the regulation of cell to cell interactions such as differentiation, adhesion, motility and death. There are currently about 90 TK genes sequenced, 58 are of receptor protein TK (e.g. EGFR, EPH, FGFR, PDGFR, TRK, and VEGFR families), and 32 of cytosolic TK (e.g. ABL, FAK, JAK, and SRC families). Three cell membrane receptor tyrosine kinases, Flt (also designated VEGFR1), Flk1 (also designated VEGFR2) and Flt4 (also designated VEGFR3), putatively involved in the growth of endothelial cells, are characterized by the presence of seven immunoglobulin like sequences in their extracellular domain. On the basis of structural similarity to Flt and Flk1, it has been speculated that Flt4 might represent a third receptor for eother VEGF or a VEGF related ligand.

Type I membrane protein.