Synonyms
Cardiotrophin-like cytokine factor 1, BSF-3
Description
Cardiotrophin-like cytokine (CLC), also referred to as novel neurotrophin-1 (NNT-1) or B cell-stimulating factor-3 (BSF-3), is a new member of the IL-6 family of structurally related cytokines that includes IL-6, CNTF, LIF, CT-1, IL-11 and OSM. All family members share the receptor subunit gp130 that belong to the type I cytokine receptor superfamily. Ligand binding leads to gp130 homodimerization or heterodimerization (with LIF receptor or OSM receptor beta ), and induces cell signaling and functional activity. For several family members, including CNTF, IL-6, and IL-11, binding of the ligand to a specific receptor alpha subunit (CNTF R alpha, IL-6 R alpha, or IL-11 R alpha ) is required prior to gp130 homo- or hetero-dimerization. CLC cDNA encodes a 225 amino acid (aa) residue precursor protein with a putative 27 aa residue signal peptide that is cleaved to yield the mature protein. Among the IL-6 family, CLC is the most homologous to cardiotrophin, having 29% aa sequence homology. CLC has been shown to bind with the soluble orphan receptor cytokine-like factor-1 (CLF) to form a heterodimeric composite cytokine that subsequently interacts with the membraneassociated CNTF R alpha to initiate gp130-LIF R dimerization and cell signaling. Alternatively, when co-expressed within the cell, CLC can complex with soluble CNTF R alpha to form an alternate composite cytokine that is secreted. This composite cytokine is also capable of initiating gp130-LIF R dimerization. The E. coli-expressed CLC can initiate cell signaling via the tripartite membraneassociated CNTF R alpha and gp130-LIF R. E. coli-expressed CLC does not bind efficiently with soluble CNTF R alpha in solution to initiate cell signaling on cells expressing gp130 and LIF R.
Molecular Weight
Approximately 22.3 kDa.
AA sequence
LNRTGDPGPG PSIQKTYDLT RYLEHQLRSL AGTYLNYLGP PFNEPDFNPP RLGAETLPRA TVDLEVWRSL NDKLRLTQNY EAYSHLLCYL RGLNRQAATA ELRRSLAHFC TSLQGLLGSI AGVMAALGYP LPQPLPGTEP TWTPGPAHSD FLQKMDDFWL LKELQTWLWR SAKDFNRLKK KMQPPAAAVT LHLGAHGF
Appearance
Sterile Filtered White lyophilized (freeze-dried) powder.
Purity
> 98 % by SDS-PAGE and HPLC analyses.
Biological Activity
The ED50 as determined by a cell proliferation assay using human TF-1 cells is less than 4 ng/mL, corresponding to a specific activity of > 2.5 × 105 IU/mg in the presence of human CNTF R alpha. Fully biologically active when compared to standard.
Endotoxin
< 0.1 EU per 1μg of the protein by the LAL method.
Formulation
Lyophilized from a 0.2 μm filtered concentrated solution in 30% Acetonitrile and 0.1% TFA.
Reconstitution
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20℃. Further dilutions should be made in appropriate buffered solutions.