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beta-Arrestin 1 and Galphaq/11 coordinately activate RhoA and stress fiber formation following receptor stimulation

William G Barnes1, Eric Reiter, Jonathan D Violin

  • 1Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.

The Journal of Biological Chemistry
|December 22, 2004
PubMed

Insights

Beta-arrestin 1, alongside G(alphaq/11) activation, is crucial for angiotensin II type 1A receptor signaling. This interaction fully activates RhoA, leading to stress fiber reorganization.

Area of Science:

  • Cellular signaling pathways
  • G protein-coupled receptor (GPCR) regulation
  • Cytoskeletal dynamics

Background:

  • Beta-arrestins (arrestin 1 and 2) are known regulators of seven-transmembrane receptor desensitization and internalization.
  • Beta-arrestin 2 mediates signaling in mitogen-activated protein kinase cascades and chemotaxis.
  • The specific role of beta-arrestin 1 in GPCR-mediated cellular responses requires further elucidation.

Purpose of the Study:

  • To investigate the role of beta-arrestin 1 in angiotensin II type 1A receptor (AT1R) signaling.
  • To determine the involvement of beta-arrestin 1 in RhoA activation and stress fiber formation downstream of AT1R.
  • To elucidate the interplay between beta-arrestin 1 and G(alphaq/11) in AT1R-mediated cellular responses.

Main Methods:

  • Utilized cell-based assays to study receptor activation and downstream signaling.
  • Investigated the activation of small GTPase RhoA.
  • Examined stress fiber formation and reorganization.
  • Focused on the angiotensin II type 1A receptor pathway.

Main Results:

  • Beta-arrestin 1 is essential for activating the small GTPase RhoA following AT1R activation.
  • RhoA activation and subsequent stress fiber formation require concurrent activation of beta-arrestin 1 and the G protein G(alphaq/11).
  • Neither beta-arrestin 1 nor G(alphaq/11) activation alone is sufficient for robust RhoA activation.

Conclusions:

  • Beta-arrestin 1 plays a critical role in AT1R-mediated RhoA activation and stress fiber reorganization.
  • The synergistic action of beta-arrestin 1 recruitment and G(alphaq/11) activation is necessary for full RhoA activation.
  • This study reveals a novel signaling mechanism involving beta-arrestin 1 in GPCR-induced cytoskeletal remodeling.

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