SMOC1 (SPARC-related Modular Calcium-binding Protein 1, Secreted Modular Calcium-binding Protein 1,

SMOC-1 (secreted, or SPARC-related, modular calcium-binding protein 1) is a 70-90kD secreted glycoprotein that is a member of the SPARC family of matricellular molecules. Mature human SMOC-1 is 408aa in length. It contains one Kazal-like domain (aa42-87), two thyroglobulin type-1 (TY) segments (aa92-159 and 224-292) and two EF-hand sequences (aa359-394 and 396-431). One potential splice variant contains a 16aa region of alternate sequence between the TY domains, a 7aa deletion between the TY and EF-hand domains, and three alternate aa at the C-terminus. Mature human SMOC-1 shares 92% aa identity with mouse and rat SMOC-1 and 97%, 96% and 95% aa identity with canine, bovine and porcine SMOC-1, respectively. The principal difference between rodents and other mammals is an additional 19aa near the C-terminus of rodent SMOC-1. Like other matricellular proteins, SMOC-1 is primarily expressed in basement membranes, although it has also been found in other extracellular matrices and the oocyte zona pellucida. It is present early in mouse embryogenesis, and is produced by cells deriving from all three germ layers. Recombinant bacterially produced human SMOC-1 and SMOC-2 were both shown to bind the acute phase protein, C-reactive protein, and the adhesion proteins, fibulin and vitronectin. A signaling role for SMOC-1 was shown in rat mesangial cells: induction of nitric oxide in response to inflammatory cytokines downregulates SMOC-1 which, in turn, downregulates expression of TGF-b and TGF-b-regulated genes. This mechanism is proposed to limit the profibrotic effects of TGF-b, for example in the glomerulus. In Xenopus, the SMOC paralog has been shown to antagonize BMP activity. Source: Murine myeloma cell line, NS0-derived His27-Val434, with a C-terminal 6-His tag. SDS-PAGE: 60-65kD, reducing conditions, Activity: Measured by the ability of the immobilized protein to support the adhesion of A431 human epidermoid carcinoma cells. When 5x10e4 cells/well are added to rhSMOC-1 coated plates, cell adhesion is enhanced in a dose dependent manner after 75 minutes at 37 °C. The ED50 for this effect is typically 0.5-2ug/ml. Endotoxin Level: <1EU/1ug (LAL) , Storage and Stability:, Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile buffer or ddH2O. 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.