The First Bioactive Wnt1 Protein: Purification of Wnt1/sFRP Complexes

Active Wnt proteins have been difficult to purify from conditioned media due to post translational modifications that render them hydrophobic and insoluble. While scientists have found that some Wnt proteins can be purified in an active state from conditioned media by overexpressing the protein, this is not the case for all Wnts including Wnt1, which is undetectable in conditioned media even when it is overexpressed. This suggests that Wnt1 is primarily associated with the plasma membrane of Wnt-producing cells, complicating the purification process.

In this study, R&D Systems™ scientists demonstrate that co-expression of secreted Frizzled-related protein 1 (sFRP1) can liberate the Wnt1 protein from the plasma membrane by binding to and shielding the palmitoleic acid moiety on the Wnt protein. This finding has enabled the development of a detergent-free method for purifying Wnt1/sFRP complexes and allows R&D Systems, a Bio-Techne brand, to offer the first commercially available, bioactive Wnt1 for research use.