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Quantitative PCR-based Assay to Measure Sonic Hedgehog Signaling in Cellular Model of Ciliogenesis
Published on: January 31, 2025
Sonic Hedgehog-induced proliferation requires specific Gα inhibitory proteins
Mercedes Barzi1, Dorota Kostrz1, Anghara Menendez1
1From the Department of Cell Death and Proliferation, Instituto de Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas, Institut d'Investigacions Biomèdiques August Pi i Sunyer, 08036 Barcelona, Spain.
The Journal of Biological Chemistry
|January 7, 2011
Summary
Sonic Hedgehog (Shh) signaling in cerebellar development relies on Gα(i2) and Gα(i3) proteins. These G proteins are crucial for the proliferation of cerebellar granular neuronal precursors (CGNPs) and localize to primary cilia.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Sonic Hedgehog (Shh) signaling regulates cerebellar granular neuronal precursor (CGNP) proliferation via the Patched and Smoothened (Smo) receptor complex.
- Smo's classification as a G protein-coupled receptor (GPCR) is debated, with controversial evidence regarding its use of heterotrimeric G proteins in vertebrate Shh signaling.
Purpose of the Study:
- To investigate the role of heterotrimeric G proteins, specifically Gα(i/o) and Gα(12) families, as downstream effectors in Shh-induced CGNP proliferation.
- To determine which specific Gα(i) members are involved in Shh signaling within the developing cerebellum.
Main Methods:
- Expression analysis of active Gα(i/o) and Gα(12) proteins in rat CGNP cultures stimulated by Shh.
- Quantitative assessment of Gα(i) mRNA expression patterns in the developing cerebellum.
- Knockdown experiments targeting specific Gα(i) members to evaluate their impact on Shh-induced CGNP proliferation.
- Localization studies of Gα(i2) and Gα(i3) in CGNP primary cilia.
Main Results:
- Active Gα(i/o) proteins (Gα(i1), Gα(i2), Gα(i3), and Gα(o)) significantly enhanced Shh-induced CGNP proliferation, while Gα(12) did not.
- Gα(i2) and Gα(i3) mRNA were predominantly expressed in the outer external granular layer, the site of CGNP proliferation.
- Knockdown of Gα(i2) and Gα(i3) significantly reduced Shh-induced CGNP proliferation, unlike other Gα(i/o) members.
- Expressed Gα(i2) and Gα(i3) were found to localize to the primary cilium in CGNP cultures.
Conclusions:
- Shh-induced proliferation of CGNPs is mediated by the synergistic action of Gα(i2) and Gα(i3) proteins.
- Gα(i2) and Gα(i3) function as critical downstream effectors of Shh signaling in cerebellar development.
- The localization of Gα(i2) and Gα(i3) to primary cilia suggests a role in Shh signal transduction within this organelle.
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