Figure 3.
Activities of RSpo proteins are dependent on an endogenous pool of Wnt ligands. Stable HEK-293 reporter cells were transfected with either nontargeting control siRNA or WLS siRNA duplexes (10 nM), treated with indicated amounts of RSpo1 (A), RSpo2 (B), RSpo3 (C), RSpo4 (D), or Wnt3A (E) proteins. Reporter activity was analyzed as described above.