The wingless/Wnt-1 Signaling Pathway—New Insights into the Cellular Mechanisms of Signal Transduction

Abstract

Publisher Summary This chapter discusses the cellular mechanisms of signal transduction that is the wingless/Wnt-1 signaling. During the development of multicellular organisms, cells acquire information that instructs them to differentiate according to their specific position within the body. The establishment and implementation of this positional information depends on cell to cell communication and on the signal transduction pathways that underlie this communication. The Drosophila segment polarity gene wingless ( wg ) and its vertebrate homologue Wnt-1 signaling molecules specify cell fates in Drosophila and mouse embryos. The segment polarity gene wg is first identified by a weak mutation that disrupts the development of adult cuticular structures, such as the wing blade. Subsequently, null mutations of wg are obtained and found to result in embryonic lethality with severe pattern defects in the cuticular structures secreted by embryonic epidermal cells. Both wg and Wnt-1 encode proteins with features typical of secreted growth factors. They are rich in cysteine residues and have a signal sequence followed by a consensus signal peptidase cleavage site at their amino-termini.