Identification and biochemical characterization of secreted Wnt-1 protein from P19 embryonal carcinoma cells induced to differentiate along the neuroectodermal lineage.

Previous studies have described Wnt-1 protein synthesized by cell lines transfected with Wnt-1 cDNA. This report presents the first identification and biochemical characterization of native Wnt-1 protein, from P19 embryonal carcinoma cells undergoing neuroectodermal differentiation. The data demonstrate that P19 cells efficiently process and secrete glycosylated Wnt-1 protein species of 40 kD and 42 kD. Similar to recombinant Wnt-1 proteins, native Wnt-1 proteins are associated with the cell surface upon secretion and can be released by suramin treatment of the cells. Non-reducing gel analysis showed that Wnt-1 proteins are secreted as monomers.