FLT3 (FMS-like tyrosine kinase 3)

993 amino acids; FLT3 is a class III receptor tyrosine kinase (RTK) structurally related to the receptors for platelet derived growth factor (PDGF), colony stimulating factor 1 (CSF1), and KIT ligand (KL); these RTK contain five immunoglobulin-like domains in the extracellular region and an intracelular tyrosine kinase domain split in two by a specific hydrophilic insertion (kinase insert); immunoprecipitation of the human FLT3 protein results in the appearance of a minor band of Mr 130 000 and a major band of Mr 155 000/160 000; the high-molecular-weight band corresponds to the mature, N-glycosylated form, and the low-molecular-weight band to the immature, high mannose-containing form; N-linked glycosylations account for 50 000 daltons. Expression