Prolyl hydroxylase 2: a novel regulator of β2 -adrenoceptor internalization.
Bottom Line: 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.
Affiliation: Key Laboratory of Arrhythmias, Ministry of Education, China (East Hospital, Tongji University School of Medicine), Shanghai, China.Show MeSH
Mentions: Subsequently, we began to explore the mechanism of PHD2 regulation of β2-AR internalization. Previous studies revealed that decreased oxygen availability contributes to the stability of β2-AR in response to agonist stimulation. β2-AR stability is tightly associated with β2-AR responsiveness and also affects the rate of β2-AR internalization . Thus, we first estimated the levels of β2-AR expression during our experiments. Western blots analysis revealed that PHD2 expression did not result in any change in β2-AR expression (Fig. S2). Moreover, no treatment caused HIF-1α induction (Fig. S3), a hypoxia indicator, implicating that all of the experiments were performed in the normoxic state and that changes in β2-AR internalization are not mediated by the actions of HIF-1α but are conferred by PHD2. In addition, consistent with previous study , β2-AR-PHD2 association was not detected in β2-AR-293 cells through coimmunoprecipitation experiments (Fig. 3A). Collectively, these results suggest that PHD2 may affect the downstream effectors of β2-AR signalling.
Affiliation: Key Laboratory of Arrhythmias, Ministry of Education, China (East Hospital, Tongji University School of Medicine), Shanghai, China.