Lrp4 ECD Inhibits Wnt signaling <i>in vitro</i>.

<p>HEK-293 cells were transfected using the TOP-Flash reporter system in the presence of the indicated plasmids (0.5 µg/construct as indicated, where required empty pcDNA3.1 plasmid DNA was added to bring the DNA concentration up to a total amount of 2.5 µg plasmid DNA/condition). Dkk1 and Lrp4 independently inhibit Wnt signaling (lane 5 and 6). Inhibition of Wnt1 induced reporter activation by co-transfection of Lrp4 ECD and Dkk-1 is synergistic (lane 7). Lrp5 and Lrp6 are co-receptors of the frizzled complex and required for Wnt1 mediated activation, however, HEK-293T cells do not express Lrp5 or 6 endogenously and thus need to be co-transfected with the respective plasmids <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009960#pone.0009960-Johnson1" target="_blank">[11]</a>.