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Inducing Dendritic Growth in Cultured Sympathetic Neurons
Published on: March 21, 2012
Highwire regulates presynaptic BMP signaling essential for synaptic growth
Brian D McCabe1, Sabrina Hom, Hermann Aberle
1Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA. bmccabe@socrates.berkeley.edu
Neuron
|March 30, 2004
Summary
Highwire (Hiw) negatively regulates synaptic growth. Its interaction with bone morphogenetic protein (BMP) signaling reveals a balance controlling neuromuscular junction (NMJ) size.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Highwire (Hiw) is an E3 ubiquitin ligase that negatively regulates synaptic growth at the Drosophila neuromuscular junction (NMJ).
- Hiw mutants exhibit enlarged synaptic size and increased bouton numbers, indicating impaired growth regulation.
Purpose of the Study:
- To investigate the molecular mechanism by which Highwire (Hiw) regulates synaptic growth.
- To determine the relationship between Hiw and bone morphogenetic protein (BMP) signaling in synaptic development.
Main Methods:
- Co-immunoprecipitation to assess binding between Hiw and Medea (Med).
- Analysis of NMJ morphology and synaptic bouton numbers in wild-type, hiw mutants, and BMP signaling mutants.
- Assessment of synaptic growth in hiw mutants upon activation of BMP signaling.
Main Results:
- Highwire (Hiw) directly binds to the Smad protein Medea (Med).
- Bone morphogenetic protein (BMP) signaling components (Wit, Tkv, Sax, Mad) are crucial for NMJ development, with mutants showing reduced size and neurotransmitter release.
- BMP signaling pathway mutants suppress the excessive synaptic growth observed in hiw mutants.
- Activating BMP signaling in hiw mutants leads to further synaptic expansion, unlike in wild-type.
Conclusions:
- Highwire (Hiw) negatively regulates synaptic growth by interacting with the Medea (Med) component of the BMP signaling pathway.
- A balance between positive BMP signaling and negative Highwire regulation governs neuromuscular junction (NMJ) synaptic growth.
- This study elucidates a novel regulatory mechanism controlling synaptic size and development.
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