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Updated: May 15, 2026

Quantitative PCR-based Assay to Measure Sonic Hedgehog Signaling in Cellular Model of Ciliogenesis
07:26

Quantitative PCR-based Assay to Measure Sonic Hedgehog Signaling in Cellular Model of Ciliogenesis

Published on: January 31, 2025

The ciliary G-protein-coupled receptor Gpr161 negatively regulates the Sonic hedgehog pathway via cAMP signaling

Saikat Mukhopadhyay1, Xiaohui Wen, Navneet Ratti

  • 1Department of Research Oncology, Genentech Inc., South San Francisco, CA 94080, USA. saikat.mukhopadhyay@utsouthwestern.edu

Cell
|January 22, 2013
PubMed

Insights

The G-protein-coupled receptor Gpr161 is crucial for Sonic hedgehog (Shh) signaling regulation in primary cilia. Its loss increases Shh signaling, impacting neural tube development.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Molecular Biology

Background:

  • The primary cilium is essential for Sonic hedgehog (Shh) signaling in vertebrates.
  • Mutations in intraflagellar transport complex A (IFT-A) paradoxically increase Shh signaling.
  • IFT-A recruits the tubby-like protein, Tulp3, to cilia.

Purpose of the Study:

  • To identify novel components involved in Shh signaling regulation within primary cilia.
  • To investigate the role of Gpr161 in Tulp3/IFT-A-dependent ciliary localization and Shh pathway modulation.

Main Methods:

  • Utilized mouse models with genetic loss of Gpr161.
  • Analyzed primary cilia localization of Gpr161 in relation to Tulp3 and IFT-A.
  • Assessed Shh signaling pathway activity and Gli3 processing in Gpr161 mutants.
  • Measured cyclic AMP (cAMP) levels and Gpr161 internalization from cilia.

Main Results:

  • Gpr161 localizes to primary cilia in a Tulp3/IFT-A-dependent manner.
  • Complete Gpr161 loss in mice leads to mid-gestation lethality and elevated neural tube Shh signaling, mimicking Tulp3/IFT-A mutants.
  • Active Gpr161 elevates cAMP, repressing Shh signaling by promoting Gli3 repressor form.
  • Shh signaling induces Gpr161 internalization from cilia, inhibiting its activity.

Conclusions:

  • Gpr161 is a key regulator of Shh signaling in primary cilia.
  • Gpr161 functions as a conserved vertebrate G-protein-coupled receptor essential for neural tube development.
  • Gpr161 defines a pathway linking protein kinase A activation to Shh signaling via cAMP modulation and Gli3 processing.

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