ST7, Recombinant, Human (Low-density Lipoprotein Receptor-related Protein 12, LRP-12, Suppressor of

ST7 (Suppressor of Tumorigenicity 7), also known as RAY1, TSG7 and FAM4A1, is a type I transmembrane protein belonging to the LDLR superfamily and is designated LRP12. The human ST7 cDNA encodes 859aa including a 32aa signal sequence, a 460aa extracellular domain (ECD) containing two CUB domains and five LDLR class A domains, a 21aa transmembrane domain, and a 346aa cytoplasmic domain containing motifs implicated in endocytosis and signal transduction. Human ST7 shares 95% aa sequence homology with mouse and rat, 96% with canine, and 98% with bovine, equine and porcine ST7 within the ECD. Genomic sequencing indicates the possibility of up to 18 splicing isoforms, but expression of these has not been well-studied. ST7 is widely expressed in normal tissues, especially fibroblasts. Highest mRNA levels were detected in heart and skeletal muscle. ST7 was originally proposed to be a tumor suppressor protein, but it is not consistently downregulated in a variety of cancers, either by mutation or loss of heterozygosity. In certain cancers, expression may even be upregulated. Expression may be associated with downregulated expression of extracellular matrix molecules that are involved in remodeling, such as SPARC, IGFBP5 and several matrix metalloproteinases, and modulation of in vivo tumorigenicity. Source: Murine myeloma cell line, NS0-derived, Asn28-Ile488 with a C-terminal 6-His tag. SDS-PAGE: 71kD, reducing conditions , Activity: Measured by its binding ability in a functional ELISA. When rhST7 is immobilized at 0.5ug/ml, the concentration of rhLRPAP that produces 50% of the optimal binding response is found to be approximately 0.6-3ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months 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.