FIGURE 4.

Knockdown of endogenous Mesd impairs the folding and secretion of LRP6 BPs. A, BHK570 cells were transfected with Mesd siRNA or control siRNA and cDNAs for BP1, -2, -3, and -4, BP12, BP34, or BP1234. Secretion of BPs was analyzed as described in the previous figures. A representative result of LRP6 BP1234 is shown. Secretion of this BP was strongly suppressed when the endogenous Mesd was knocked down. B, quantification of secretion efficiency of LRP6β-propellers from Western blot analyses. Values are the average of triple determinations from at least two independent experiments with the S.D. indicated by error bars.