S-nitrosylation of pVHL regulates β₂ adrenergic receptor function

Area of Science:

• Molecular Biology
• Physiology
• Cellular Signaling

Background:

• The beta-2 adrenergic receptor (β2AR) is crucial for cardiopulmonary function and O2 delivery.
• Canonical regulation of β2AR abundance involves G protein-coupled receptor kinases and β-arrestins.
• Constitutive β2AR levels, independent of canonical pathways, are modulated by ambient O2 via the prolyl hydroxylase/pVHL-E3 ubiquitin ligase system.

Purpose of the Study:

• To elucidate the role of the prolyl hydroxylase/pVHL-E3 ubiquitin ligase system in O2-dependent β2AR regulation.
• To investigate the interplay between oxygen (O2) and nitric oxide (NO) in controlling pulmonary function.
• To determine how NO influences β2AR expression and signaling.

Main Methods:

• Investigated the effect of NO on pVHL-mediated β2AR degradation.
• Utilized S-nitrosylation assays to examine NO's interaction with pVHL.
• Employed pVHL-C43S mutant mice to assess the in vivo impact of impaired S-nitrosylation on β2AR signaling and airway tone.

Main Results:

• Nitric oxide (NO) counteracts pVHL-mediated degradation of β2AR.
• NO S-nitrosylates Cys77 in human pVHL (Cys43 in mouse), promoting c-Cbl binding and pVHL degradation, thus increasing β2AR expression.
• pVHL-C43S mutant mice, unable to undergo S-nitrosylation, showed reduced β2AR signaling and increased airway tone.

Conclusions:

• pVHL plays a critical role in controlling adrenergic pulmonary function.
• NO contributes to bronchodilation by inhibiting pVHL-mediated β2AR degradation.
• The findings suggest novel therapeutic strategies for asthma and obstructive airway diseases.