Recombinant Human FIt-3 Ligand/FLT3L (His, Flag)

Flt3 ligand (FL) is a recently discovered hematopoietic cytokine whose activity is mediated through binding to the transmembrane glycoprotein Flt3. Flt3 was first identified as a member of the class III subfamily of receptor tyrosine kinases (RTKs), and its expression in hematopoietic cells is restricted to highly enriched stem/progenitor cell populations. Furthermore, class III RTKs include the receptors for SCF, M-CSF, and PDGF. Not surprisingly, Flt3 ligand is also structurally related to M-CSF and SCF. All three cytokines exist as both type I transmembrane proteins and soluble proteins. The major human FL isoform is a transmembrane protein that can undergo proteolytic cleavage to generate a soluble form of the protein. Additionally, an alternatively spliced FL mRNA encoding a soluble form of human FL has been identified. FL is widely expressed in various tissues in both humans and mice. At the amino acid sequence level, human and mouse FL are approximately 72% identical, and the two proteins exhibit cross-species activity. FL has been shown to synergize with multiple hematopoietic cytokines to stimulate the growth and differentiation of early hematopoietic progenitor cells.

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