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Flt-3 Ligand(FLT3L)is an alpha-helical cytokine that promotes the differentiation of multiple hematopoietic cell lineages (1-3). Mature mouse Flt-3 Ligand consists of a 161 amino acid (aa) extracellular domain (ECD) with a cytokine-like domain and a juxtamembrane tether region, a 21 aa transmembrane segment, and a 22 aa cytoplasmic tail (4-6). Within the ECD, mouse Flt-3 Ligand shares 71% and 81% aa sequence identity with human and rat Flt-3 Ligand, respectively. The mouse and human Flt-3 Ligand proteins show cross-species activity (4, 5, 7). Flt-3 Ligand is also structurally related to M-CSF and SCF. Flt-3 Ligand is widely expressed in various mouse and human tissues. Flt-3 Ligand is expressed as a noncovalently-linked dimer by T cells and bone marrow and thymic fibroblasts (1, 8). Each 36 kDa chain of the Flt-3 Ligand dimer carries approximately 12 kDa of N- and O-linked carbohydrates (8). Alternate splicing and proteolytic cleavage of the transmembrane form of the Flt-3 Ligand protein can generate a soluble 30 kDa fragment that includes the cytokine-like domain (4, 8). Alternate splicing of mouse Flt-3 Ligand also generates a membrane-associated isoform with a 57 aa substitution following the cytokine-like domain in the ECD of the Flt-3 Ligand protein (4, 5, 8, 9). Both transmembrane and soluble Flt-3 Ligand signal through the tyrosine kinase receptor Flt-3/Flk-2 (3 - 6). Flt-3 Ligand induces the expansion of monocytes and immature dendritic cells as well as early B cell lineage differentiation (2, 10). Additionally, Flt-3 Ligand synergizes with IL-3, GM-CSF, and SCF to promote the mobilization and myeloid differentiation of hematopoietic stem cells (4, 5, 7). Flt-3 Ligand also cooperates with IL-2, IL-6, IL-7, and IL-15 to induce NK cell development and with IL-3, IL-7, and IL-11 to induce terminal B cell maturation (1, 11). Animal studies also show that Flt-3 Ligand reduces the severity of experimentally induced allergic inflammation (12).

Reference

1. Wodnar-Filipowicz, A. (2003) News Physiol. Sci. 18:247.

2. Dong, J. et al. (2002) Cancer Biol. Ther. 1:486.

3. Gilliland, D.G. and J.D. Griffin (2002) Blood 100:1532.

4. Hannum, C. et al. (1994) Nature 368:643.

5. Lyman, S.D. et al. (1993) Cell 75:1157.

6. Savvides, S.N. et al. (2000) Nat. Struct. Biol. 7:486..

7. Lyman, S.D. et al. (1994) Blood 83:2795.

8. McClanahan, T. et al. (1996) Blood 88:3371.

9. Lyman, S.D. et al. (1995) Oncogene 10:149.

10. Diener, K.R. et al. (2008) Exp. Hematol. 36:51.

11. Farag, S.S. and M.A. Caligiuri (2006) Blood Rev. 20:123.

12. Edwan, J.H. et al. (2004) J. Immunol. 172:5016.

Specifications

Synonyms	FL; FLG3L; Flt3 ligand; Flt-3 Ligand; Flt3L; FLT3LG; fms-related tyrosine kinase 3 ligand; SL cytokine
Accession #	P49772
Source	Human embryonic kidney cell, HEK293-derived mouse Flt-3 Ligand/FLT3L protein
Source	Gly27-Arg188
Predicted Moleucular weight	18.4 kDa

Components and Storage

Formulation	Solution protein
	Dissolved in sterile PBS buffer.
	This solution can be diluted into other aqueous buffers. Centrifuge the vial prior to opening
Storage and Stability	Avoid repeated freeze-thaw cycles.
	It is recommended that the protein be aliquoted for optimal storage.
	12 months from date of receipt, -20 to -70 °C as supplied.
Shipping	Shipping with dry ice

Quality

Purity	> 95%, determined by SDS-PAGE
Endotoxin Level	<0.010 EU per 1 ug of the protein by the LAL method
Activity	Measured in a cell proliferation assay using BaF3 mouse pro-B cells transfected with mouse Flt-3.
Activity	The EC50 for this effect is typically 0.04-2.4 ng/mL.

SDS-PAGE

Bioactivity

Documents

Mouse FLT3L