arrow encodes an LDL-receptor-related protein essential for Wingless signalling

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Wnt signaling is crucial for cell-fate determination and morphogenesis in development.
• Components of the Wingless (Drosophila Wnt) signal transduction cascade, including Frizzled receptors, are known.
• The precise mechanism of Wingless signal reception and transduction across the cell membrane remains incompletely understood.

Purpose of the Study:

• To identify and characterize genes essential for Wingless signaling in Drosophila.
• To elucidate the mechanism of Wingless signal reception at the cellular level.

Main Methods:

• Genetic analysis in Drosophila to identify genes required for Wingless signaling.
• Molecular characterization of the identified gene, 'arrow'.
• Biochemical and structural analysis to determine the function and localization of the Arrow protein.

Main Results:

• The 'arrow' gene is essential for all Wingless signaling events in Drosophila.
• Arrow functions in cells that receive Wingless input and acts upstream of Dishevelled.
• Arrow encodes a single-pass transmembrane protein, homologous to the low-density lipoprotein receptor-related protein (LRP) subfamily (LRP5/6).

Conclusions:

• Arrow acts as a key component in the Wingless/Wnt signal reception complex, potentially with Frizzled proteins.
• This study identifies a novel and conserved function for LRPs in Wingless/Wnt signal reception.
• The findings provide new insights into the molecular mechanisms underlying Wnt pathway activation.