Recombinant Human SCUBE3 Protein, CF

SCUBE3 (signal peptide, CUB and EGF-like domain-containing protein 3) is a member of the SCUBE family of secreted glycoproteins (1). Like other SCUBE proteins, the 993 amino acid (aa) human SCUBE3 precursor contains a signal peptide (aa 1‑20), nine EGF‑like motifs (aa 29‑398), a linker region with multiple N‑glycosylation sites (aa 399‑803) and a C‑terminal CUB domain (aa 804‑916). Cysteines within the EGF‑like and linker regions are mainly conserved (1). The 130 kDa, mature, full‑length form of human SCUBE3 shares 96%, 93%, 96%, 95%, 95% and 94% aa sequence identity with mouse, rat, equine, bovine, canine and porcine SCUBE3, respectively (1). It also shares 66% and 58% aa identity with human SCUBE1 and SCUBE2, respectively. Cleavage by proteases such as MMP‑2 and MMP‑9 produces a CUB domain-containing, 55 kDa fragment that, like full‑length SCUBE3, binds TGF-beta RII (1, 2). SCUBE proteins form homo-oligomers and hetero‑oligomers, and are predicted to affect TGF‑ beta and Hedgehog signaling (2‑5). SCUBE3 is most highly expressed in osteoblasts (1, 3, 6). It is also found in umbilical vein endothelial cells with SCUBE1 and SCUBE2, and in cardiac ventricular myocytes (1, 3, 6). Transgenic over-expression of SCUBE3 can cause progressive cardiac hypertrophy (3). SCUBE3 and its active fragment are frequently over‑expressed in lung cancer tumor tissues, and can promote epithelial to mesenchymal transition by enhancing TGF-beta signaling pathways (2).