Purity ≥90% (SDS-PAGE) under reducing conditions and visualized by silver stain. Endotoxin: ≤1EU/ug (LAL). RSpondin 1 (RSPO1, Roof platespecific Spondin 1), also known as cysteinerich and single thrombospondin domain containing protein 3 (Cristin 3), is a 27kD secreted protein that shares ~40% amino acid (aa) identity with three other RSpondin family members. All RSpondins regulate Wnt/bcatenin signaling, but have distinct expression patterns. Like other RSpondins, RSpondin 1 contains two adjacent cysteinerich furinlike domains (aa34135) with one potential Nglycosylation site, followed by a thrombospondin (TSP1) motif (aa147207) and a region rich in basic residues (aa211263). Only the furinlike domains are needed for bcatenin stabilization. A putative nuclear localization signal at the Cterminus may allow some expression in the nucleus. Potential isoforms of 200 and 236aa have an alternate, shorter Nterminus or are missing aa146208, respectively. Over aa21263, hum