
Hedgehog signaling requires motile cilia in the sea urchin.
A relatively small number of signaling pathways govern the early patterning processes of metazoan development. The architectural changes over time to these signaling pathways offer unique insights into their evolution. In the case of Hedgehog (Hh) signaling, two very divergent mechanisms of pathway transduction have evolved. In vertebrates, signaling relies on trafficking of Hh pathway components to nonmotile specialized primary cilia. In contrast, protostomes do not use cilia of any kind for Hh signal transduction. How these divergent lineages adapted such dramatically different ways of activating the signaling pathway is an unanswered question. Here, we present evidence that in the sea urchin, a basal deuterostome, motile cilia are required for embryonic Hh signal transduction, and the Hh receptor Smoothened (Smo) localizes to cilia during active Hh signaling. This is the first evidence that Hh signaling requires motile cilia and the first case of an organism requiring cilia outside of the vertebrate lineage.
Duke Scholars
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Signal Transduction
- Sea Urchins
- Receptors, G-Protein-Coupled
- Microscopy, Electron, Scanning
- Hedgehog Proteins
- Evolutionary Biology
- Evolution, Molecular
- Cilia
- Animals
- 3105 Genetics
Citation

Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Signal Transduction
- Sea Urchins
- Receptors, G-Protein-Coupled
- Microscopy, Electron, Scanning
- Hedgehog Proteins
- Evolutionary Biology
- Evolution, Molecular
- Cilia
- Animals
- 3105 Genetics