Syndecan defines precise spindle orientation by modulating Wnt signaling in C. elegans
Katsufumi Dejima1, Sukryool Kang2, Shohei Mitani3
1Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Development (Cambridge, England)
|October 26, 2014
Summary
Syndecan (SDN-1) is crucial for guiding mitotic spindle orientation during development. This heparan sulfate proteoglycan ensures precise Wnt signal response, preventing spindle misorientation in early C. elegans embryos.
Area of Science:
- Developmental Biology
- Cell Biology
- Molecular Biology
Background:
- Wnt signaling plays a key role in orienting mitotic spindles during embryonic development.
- The precise spatial control mechanisms for Wnt-mediated spindle orientation remain incompletely understood.
Purpose of the Study:
- To investigate the role of C. elegans syndecan (SDN-1) in Wnt-dependent mitotic spindle orientation.
- To elucidate the molecular mechanisms underlying spatial Wnt signaling control for spindle positioning.
Main Methods:
- Utilized C. elegans as a model organism for studying early embryonic development.
- Investigated the function of syndecan (SDN-1) and heparan sulfate (HS) biosynthesis in spindle orientation.
- Analyzed the localization and function of SDN-1 and Dishevelled (MIG-5) in response to Wnt cues and cell-cell contact.
Main Results:
- SDN-1, the primary heparan sulfate proteoglycan in early C. elegans embryos, is essential for correct mitotic spindle orientation.
- Loss of HS biosynthesis or SDN-1 core protein leads to ABar blastomere spindle misorientation.
- SDN-1 is required for Wnt-induced ABar spindle reorientation, dependent on new cell contact and local Dishevelled (MIG-5) accumulation.
Conclusions:
- Syndecan (SDN-1) plays a novel and critical role in Wnt-dependent mitotic spindle orientation.
- SDN-1 acts as a key mediator in spatially controlling Wnt signals for precise spindle positioning.
- This study reveals a new mechanism involving heparan sulfate proteoglycans in developmental cell polarity.
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