Active Wnt proteins are secreted on exosomes

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Wnt signaling is crucial for embryonic development and disease pathogenesis.
• Wnt proteins function as morphogens, regulating cell fate decisions over distance.
• The extracellular transport mechanism of Wnt proteins remains poorly understood.

Purpose of the Study:

• To investigate the mechanism of Wnt protein secretion and extracellular transport.
• To determine the role of exosomes in Wnt protein trafficking.
• To elucidate the evolutionary conservation of Wnt transport.

Main Methods:

• Utilized Drosophila melanogaster and human cell culture models.
• Investigated Wnt protein localization and secretion using biochemical and imaging techniques.
• Analyzed the role of specific proteins (Evi/WIs, Ykt6) in Wnt transport.

Main Results:

• Demonstrated that Wnt proteins are secreted on the surface of exosomes.
• Showed that exosomes carrying Wnt proteins induce signaling activity in target cells.
• Identified Evi/WIs as a cargo receptor and Ykt6 as a required R-SNARE for Wnt exosomal transport.

Conclusions:

• Wnt proteins are transported extracellularly via exosomes in an evolutionarily conserved manner.
• Exosomal transport is essential for Wnt morphogenetic function.
• This finding provides a new understanding of Wnt signaling regulation.