PT - JOURNAL ARTICLE AU - van Amerongen, Renée AU - Mikels, Amanda AU - Nusse, Roel TI - Alternative Wnt Signaling Is Initiated by Distinct Receptors AID - 10.1126/scisignal.135re9 DP - 2008 Sep 02 TA - Science Signaling PG - re9--re9 VI - 1 IP - 35 4099 - http://stke.sciencemag.org/content/1/35/re9.short 4100 - http://stke.sciencemag.org/content/1/35/re9.full SO - Sci. Signal.2008 Sep 02; 1 AB - An unanswered question in the field of signal transduction research is how different signaling pathways are activated with strict specificity in a temporally and spatially controlled manner. Because extracellular ligands and membrane receptors constitute the first signaling modalities for most pathways, selectivity in ligand-receptor binding likely dictates the outcome of downstream signaling events. Unfortunately, possible complexities underlying ligand-receptor interactions are often overlooked. Here, we discuss basic principles of signal transduction initiated at the cell membrane, with the Wnt pathway, which harbors a multitude of ligands and receptors, as an example.