Macrophage stimulating protein (MSP), also known as HGF-like protein and scatter factor-2, is a member of the HGF family of growth factors. MSP is secreted as an inactive single chain precursor (pro-MSP) that contains a PAN/APPLE-like domain, four kringle domains, and a peptidase S1 domain which lacks enzymatic activity. Human MSP shares 79% aa sequence identity with mouse MSP and 44% aa sequence identity with human HGF. Pro-MSP is secreted by hepatocytes under the positive and negative control of CBP in complex with either HNF-4 or RAR, respectively. Circulating pro-MSP is proteolytically cleaved in response to tissue injury to yield biologically active disulfide linked heterodimers consisting of a 45-62kD alpha and a 25-35kD beta chain. Pro-MSP can be activated by MT-SP1, a transmembrane protease that is expressed on macrophages and is upregulated in many cancers. Heterodimeric MSP, as well as the isolated beta chain, binds to MSP R/Ron with high-affinity, although only heterodimeric MSP can induce receptor dimerization and signaling. MSP induces macrophage and keratinocyte proliferation and osteoclast activation. It also inhibits LPS- or IFN-induced iNOS and IL-12 expression by macrophages and prevents apoptosis of epithelial cells separated from the ECM . The substitution of cysteine 672 (in the beta chain) with alanine significantly increases the bioactivity of recombinant MSP, apparently by limiting incorrect disulfide bond formation between the alpha and beta chains.
A DNA sequence encoding human MSP (Gln19-Arg483 (alpha) and Val484-Gly711 (Cys672Ala) (beta), NCBI Accession #AAA59872, with C672A mutation was expressed in Chinese Hamster Ovary cells. This MSP protein is a disulfide-linked heterodimer.
Bioloigical Activity:Measured by its ability to activate MSP R/Ron in a human breast cancer cell line, MDA-MB-453 or T47D. 80ng/ml of the reombinant human MSP (C672A) significantly induces phosphorylation of MSP R/Ron.
Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS containing ≥0.1% BSA or HSA. Aliquot to avoid repeated freezing and thawing. Store at -20°C. 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.
仕様
Size：10ug
Source Antigen：Chinese Hamster Ovary (CHO) cells
Grade：Highly Purified
Purity：≥95% as determined by SDS-PAGE and visualized by silver stain. Endotoxin (LAL): ≤0.1EU/1ug
Form：Supplied as a lyophilized powder from PBS, with 50ug BSA per 1ug as a carrier protein. Reconstitute to a concentration of 0.01mg/ml with PBS containing ≥0.1% BSA or HSA.
