期刊
AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY
卷 35, 期 1, 页码 127-132出版社
AMER THORACIC SOC
DOI: 10.1165/rcmb.2006-0044OC
关键词
clathrin; dopamine; hypoxia; kidney tubule cells; lung alveolar cells
资金
- NHLBI NIH HHS [HL-48129, P01HL-071643] Funding Source: Medline
- NIDDK NIH HHS [DK62195] Funding Source: Medline
Activation of G protein-coupled receptor by dopamine and hypoxia-generated reactive oxygen species promote Na+, K+-ATPase endocytosis. This effect is clathrin dependent and involves the activation of protein kinase C (PKC)-zeta and phosphorylation of the Na+, K+-ATPase alpha-subunit. Because the incorporation of cargo into clathrin vesicles requires association with adaptor proteins, we studied whether phosphorylation of adaptor protein (AP)-2 plays a role in its binding to the Na+, K+-ATPase alpha-subunit and thereby in its endocytosis. Dopamine induces a time-dependent phosphorylation of the AP-2 mu 2 subunit. Using specific inhibitors and dominant-negative mutants, we establish that this effect was mediated by activation of the adaptor associated kinase 1/PKC-zeta isoform. Expression of the AP-2 mu 2 bearing a mutation in its phosphorylation site (T156A) prevented Na+, K+-ATPase endocytosis and changes in activity induced by dopamine. Similarly, in lung alveolar epithelial cells, hypoxia-induced endocytosis of Na+, K+-ATPase requires the binding of AP-2 to the tyrosine-based motif (Tyr-537) located in the Na+, K+-ATPase alpha-subunit, and this effect requires phosphorylation of the AP-2 mu 2 subunit. We conclude that phosphorylation of AP-2 mu 2 subunit is essential for Na+, K+-ATPase endocytosis in response to a variety of signals, such as dopamine or reactive oxygen species.
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