Interleukin-3(IL-3) stimulates the proliferation of hematopoietic pluripotent progenitor cells. It is secreted by activated T cells to support growth and differentiation of T cells from the bone marrow in an immune response. IL-3 exerts its biological activities through binding to specific cell surface receptors. IL-3 receptor is a complex consisting of alpha and beta subunits, which in turn induces activation of JAK2/ STAT5, induction of c-myc, and activation of the Ras pathway. Human IL3 is a protein of 15-17kD (133aa). It is synthesized as a precursor containing a hydrophobic secretory signal sequence of 19aa. IL3 contains two putative glycosylation sites at positions 15 and 70 and contains a single disulfide bond (Cys16/84). Source: Recombinant protein corresponding to aa20-152 from human Interleukin-3 fused to His-tag at N-terminal, expressed in E. coli. Molecular Weight: ~17.3kD (154aa) Biological Activity: Measured in a cell proliferation assay using TF1 human erythroleukemic cells, the ED50 for this effect is <0.53ng/ml. Activity Assay: 1. Cell line: TF1 (human erythroleukemic cell) 2. Maintenance Condition: 10% FBS RPMI 1640 with GM-CSF 3. Assay medium: 10% FBS RPMI 1640 without Gm-CSF 4. Cell density: 2x10e4cells/well (96 well plate, final volume 100ul) 5. Starvation: 24hr, Assay medium 6. Incubation time: 24hr (after sample treatment) 7. Concentration range: 0.048-25ng/ml 8. Detection method: MTT assay Amino Acid Sequence: MGSSHHHHHH SSGLVPRGSH MAPMTQTTSL KTSWVNCSNM IDEIITHLKQ PPLPLLDFNN LNGEDQDILM ENNLRRPNLE AFNRAVKSLQ NASAIESILK NLLPCLPLAT AAPTRHPIHI KDGDWNEFRR KLTFYLKTLE NAQAQQTTLS LAIF Endotoxin: ~1EU/1ug of protein (LAL) Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing.. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
