FLT3

Fms-like tyrosine kinase-3 (FLT3) is a Type III receptor tyrosine kinase expressed by hematopoietic progenitor cells. FLT3 is also sometimes referred to as FLK2 or CD135. The FLT3 protein exists in two states- membrane bound (160 kDa) and cytoplasmic (140 kDa) (1). The FLT3 ligand induces autophosphorylation of FLT3 which allows binding of scaffold and effector molecules. Activated FLT3 is capable of phosphorylating and activating PI3K, PLC-γ, Shc, Grb2, and Src (2). FLT3 signaling ultimately activates the AKT and MAPK pathways to promote cell growth and survival.

FLT3 is a Type III tyrosine kinase cell surface receptor found on primitive bone marrow stem cells. The FLT3 ligand is a hematopoietic growth factor that stimulates cells via a set of structurally related tyrosine kinase receptors.  This FLT3 Ligand promotes the differentiation of multiple hematopoietic cell lineages and is expressed as a non-covalently-linked dimer by T-cells, bone marrow, and thymic fibroblasts.