Leukemia inhibitory factor (LIF) is a 20 kD protein that belongs to the IL-6 receptor family. It binds to a heterodimeric receptor composed of a type I transmembrane ligand-binding subunit, the LIF-specific subunit gp190 (LIFR), and the type I transmembrane signal transducing subunit gp130, shared with the other members of the IL-6 family. It especially signals through STAT3 and JAK kinases. LIF expression has been observed in various tissues including thymus, lung, and neuronal tissues. LIF displays diverse biological effects, but is best known for its ability to inhibit the differentiation of embryonic stem cells in mice and contribute to stem cell self-renewal. LIF can be upregulated by proinflammatory cytokines such as TNF-α and IL-17, and elevated levels of LIF have been found in cases of rheumatoid arthritis, neural injury, systemic inflammation, and tuberculosis. Human and mouse LIF share 79% sequence homology and exhibit cross-species activity. However, LIF inhibition of stem cell differentiation appears to be mouse-specific. It is involved in the induction of hematopoietic differentiation in normal and myeloid leukemia cells, induction of neuronal cell differentiation, regulator of mesenchymal to epithelial conversion during kidney development, and may also have a role in immune tolerance at the maternal-fetal interface. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene.
Mouse LIF, amino acids (Ser24-Phe203) (Accession# NP_032527.1), was expressed in E. coli.
Molecular Mass
This 180 amino acid protein has a predicted molecular mass of approximately 20 kD. The protein migrates at approximately 20 kD in DTT-reducing conditions and approximately 18 kD in non-reducing condition by SDS-PAGE. The predicted N-terminal amino acid is Ser.
Purity
>98%, as determined by Coomassie stained SDS-PAGE
Formulation
Lyophilized in sterile-filtered PBS, pH 7.2, containing 1% BSA, 0.09% sodium azide, and protease inhibitors
Concentration
Lot-specific (please contact technical support for mass/vial, or use our Lookup tool if you have a lot number.)
Storage & Handling
Immediately upon receipt, store unopened vials between 2°C and 8°C and use within 12 months from date of receipt. Prior to use, reconstitute the lyophilized powder with 0.2 ml of PBS containing a carrier protein (e.g., 1% BSA, protease free), pH 7.4. Re-cap vial, vortex. Allow the reconstituted standard to sit at room temperature for 15 minutes, vortex again to mix completely. The reconstituted standard stock solution can be aliquoted into polypropylene vials and stored at -70°C for up to one month. Do not re-use diluted standards. Use a manual defrost freezer and avoid repeated freeze thaw cycles.
Each lot of this protein is quality control tested by ELISA assay. For use as an ELISA standard, a standard curve comprised of doubling dilutions from 1200 to 18.75 pg/mL is suggested. It is recommended that the reagent be titrated for optimal performance for each application.
Application Notes
This mouse LIF protein is useful as a standard for a mouse LIF sandwich ELISA, using unlabeled Poly5232 antibody (Cat. No. 523201) as capture and biotinylated Poly5232 antibody (Cat. No. 523204) as detection.
