Prolyl hydroxylase 2: a novel regulator of β(2)-adrenoceptor internalization

Adrenergic receptor (AR)-mediated signalling is modulated by oxygen levels. Prolyl hydroxylases (PHDs) are crucial for intracellular oxygen sensing and organism survival. However, it remains to be clarified whether or how PHDs are involved in the regulation of β(2)-adrenoceptor (β(2)-AR) signalling. Here we show that PHD2 can modulate the rate of β(2)-AR internalization through interactions with β-arrestin 2. PHD2 hydroxylates β-arrestin 2 at the proline (Pro)(176), Pro(179) and Pro(181) sites, which retards the recruitment of β-arrestin 2 to the plasma membrane and inhibits subsequent co-internalization with β(2)-AR into the cytosol. β(2)-AR internalization is critical to control the temporal and spatial aspects of β(2)-AR signalling. Identifying novel regulators of β(2)-AR internalization will enable us to develop new strategies to manipulate receptor signalling and provide potential targets for drug development in the prevention and treatment of diseases associated with β(2)-AR signalling dysregulation.