Wingless/Wnt signal transduction requires distinct initiation and amplification steps that both depend on Arrow/LRP

Shahana Baig-Lewis, Wynne Peterson-Nedry, Marcel Wehrli

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Members of the Wg/Wnt family provide key intercellular signals during embryonic development and in the maintenance of homeostatic processes, but critical aspects of their signal transduction pathways remain controversial. We have found that canonical Wg signaling in Drosophila involves distinct initiation and amplification steps, both of which require Arrow/LRP. Expressing a chimeric Frizzled2-Arrow protein in flies that lack endogenous Wg or Arrow showed that this construct functions as an activated Wg receptor but is deficient in signal amplification. In contrast, a chimeric Arrow protein containing the dimerization domain of Torso acted as a potent amplifier of Wg signaling but could not initiate Wg signaling on its own. The two chimeric proteins synergized, so that their co-expression largely reconstituted the signaling levels achieved by expressing Wg itself. The amplification function of Arrow/LRP appears to be particularly important for long-range signaling, and may reflect a general mechanism for potentiating signals in the shallow part of a morphogen gradient.

Original languageEnglish (US)
Pages (from-to)94-111
Number of pages18
JournalDevelopmental Biology
Issue number1
StatePublished - Jun 1 2007
Externally publishedYes


  • Arrow
  • Axin
  • Frizzled
  • LRP
  • Morphogen gradient
  • Signal amplification
  • Wingless
  • Wnt signaling

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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