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Updated: Jul 10, 2026
09:07
Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration
Published on: March 17, 2014
Cullin 5 regulates Dab1 protein levels and neuron positioning during cortical development
Libing Feng1, Nathaniel S Allen, Sergi Simo
1Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
Genes & Development
|November 3, 2007
Summary
Reelin signaling in brain development is regulated by the degradation of Disabled-1 (Dab1) protein. This process involves Cullin 5 (Cul5) and SOCS proteins, crucial for controlling neuronal migration and cortical layering.
Area of Science:
- Neuroscience
- Cell Biology
- Developmental Biology
Background:
- Mammalian brain development relies on neuronal precursor cell migration, guided by Reelin signaling.
- The precise mechanisms for down-regulating Reelin signaling, particularly the degradation of intracellular components like Disabled-1 (Dab1), remain poorly understood.
- Dab1 is a critical signaling molecule in Reelin pathways, and its controlled degradation is hypothesized as a negative feedback mechanism.
Purpose of the Study:
- To elucidate the molecular mechanisms responsible for the down-regulation of Reelin signaling.
- To investigate the role of Disabled-1 (Dab1) degradation in regulating neuronal migration during cortical development.
- To identify the key proteins involved in targeting Dab1 for degradation.
Main Methods:
- Investigated Dab1 degradation in tissue culture cells, focusing on phosphorylation events and E3 ubiquitin ligase involvement.
- Utilized genetic ablation of Cullin 5 (Cul5) in migrating neurons to assess its in vivo function.
- Analyzed the consequences of Cul5 deficiency on Dab1 protein levels and cortical layering.
Main Results:
- Demonstrated that Dab1 degradation is dependent on its phosphorylation at specific tyrosine residues and the E3 ubiquitin ligase Cullin 5 (Cul5).
- Showed that Cul5 forms complexes with SOCS (suppressors of cytokine signaling) proteins to mediate the ubiquitination and degradation of phosphorylated Dab1.
- Revealed that ablation of Cul5 in vivo leads to accumulation of active Dab1 and a distinct cortical layering defect characterized by neuronal over-migration.
Conclusions:
- Cullin 5 (Cul5) and SOCS proteins are implicated in the in vivo down-regulation of Dab1.
- Cul5 plays a critical role in regulating neuronal migration during mammalian cortical development.
- The findings suggest Cul5 may counteract the promigratory effects of Dab1, ensuring proper brain structure formation.
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