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Receptor Autoradiography Protocol for the Localized Visualization of Angiotensin II Receptors
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Angiotensin II AT1 receptor constitutive activation: from molecular mechanisms to pathophysiology

Christophe Petrel1, Eric Clauser

  • 1Institut Cochin, INSERM U567, University Paris Descartes, CNRS UMR8104, Paris, France.

Molecular and Cellular Endocrinology
|December 9, 2008
PubMed

Insights

Activating mutations in the angiotensin II AT(1) receptor, often in transmembrane domains, unlock receptor activation mechanisms and G protein signaling. These mutations cause hypertension and cardiovascular issues in mice, but haven't been found in human diseases.

Area of Science:

  • Pharmacology
  • Molecular Biology
  • Cardiovascular Research

Background:

  • The angiotensin II type 1 receptor (AT(1)R) is a G protein-coupled receptor (GPCR) crucial for regulating blood pressure and cardiovascular function.
  • Understanding AT(1)R activation mechanisms is vital for deciphering its role in pathophysiology and developing targeted therapies.
  • Constitutively active mutations provide insights into receptor dynamics and signaling pathway activation.

Purpose of the Study:

  • To identify and characterize mutations that activate the angiotensin II AT(1) receptor.
  • To elucidate the structural and dynamic changes associated with AT(1)R activation.
  • To investigate the downstream signaling pathways and potential pathophysiological relevance of these mutations.

Main Methods:

  • Analysis of constitutively activated AT(1)R mutants, primarily located in transmembrane domains (TM).
  • Characterization of receptor activation through the study of intramolecular constraints and TM movements.
  • Assessment of Gq-linked signaling, receptor internalization, and potential G protein-independent pathways.
  • In vivo studies involving the expression of these mutations in mouse models.

Main Results:

  • Constitutively active AT(1)R mutations are predominantly found in TM domains.
  • Receptor activation necessitates the release of intramolecular constraints and TM movements.
  • These mutations lead to constitutive activation of Gq-linked signaling pathways and receptor internalization.
  • Expression of mutated AT(1)R in mice is associated with hypertension and cardiovascular diseases.

Conclusions:

  • AT(1)R activation is intrinsically linked to structural rearrangements within its transmembrane domains.
  • Constitutive AT(1)R activation drives specific signaling cascades and cellular responses.
  • While AT(1)R mutations are implicated in cardiovascular pathology in animal models, natural human pathological instances remain unidentified.

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