The Wnt cell-cell signaling pathway plays a critical and evolutionarily con
served role in directing cell fates during embryogenesis. In addition, inap
propriate activation of the Wnt signal transduction pathway plays a role in
a variety of human cancers. Many recent studies of Wnt signaling have prov
ided mechanistic insight into these dual roles. Here we focus on two areas
of rapid advance: (i) the machinery that regulates the stability of the key
signal transducer, beta-catenin, and (ii) the effect of Wnt signaling on c
ellular targets outside the nucleus, the actin and microtubule cytoskeleton
s.