Discription：Flt3-ligand （FL） is a recently identified hematopoietic cytokine whose activities are mediated by binding to the transmembrane glycoprotein Flt3. Flt3 was first discovered as a member of the class III subfamily of receptor tyrosine kinases （RTK） whose expression among hematopoietic cells was found to be restricted to highly enriched stem/progenitor cell populations. Additionally, class III RTKs include the receptors from SCF, M-CSF and PDGF. Flt3-Ligand binds to cells expressing the tyrosine kinase receptor Flt3. Flt3-Ligand by itself does not stimulate proliferation of early hematopoietic cells, but synergizes with other CSFs and interleukins to induce growth and differentiation. Unlike SCF, Flt3-Ligand exerts no activity on mast cells. Multiple isoforms of Flt3-Ligand have been identified. The predominant biologically active form is anchored to the cell surface as the extracellular domain of a transmembrane protein （209a.a.） . The membrane-bound isoform can be proteolytically cleaved to generate a biologically active soluble isoform. Recombinant Human Flt3-Ligand is a soluble 17.6kDa protein consisting of 155 amino acid.
