WNT SIGNALING - WHY IS EVERYTHING SO NEGATIVE

The Wnt proteins constitute a family of secreted glycoproteins the mem bers of which have essential signaling roles during embryogenesis. The recent identification of several new regulators of this signal transd uction pathway have revealed unexpectedly intricate levels of constrai nt on Wnt-dependent gene activation, and studies in developing embryos and in cell culture systems have allowed a more complete understandin g of the functional and biochemical interactions between components of this evolutionarily conserved pathway. (C) Current Biology Ltd ISSN 0 955-0674.