Phosphorylation of adaptor protein-2 μ2 is essential for Na +,K+-ATPase endocytosis in response to either G protein-coupled receptor or reactive oxygen species

Zongpei Chen, Rafael T. Krmar, Laura Dada, Riad Efendiev, Ingo B. Leibiger, Carlos H. Pedemonte, Adrian I. Katz, Jacob I. Sznaider, Alejandro M. Bertorello*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

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)-ζ and phosphorylation of the Na+,K+-ATPase α-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 α-subunit and thereby in its endocytosis. Dopamine induces a time-dependent phosphorylation of the AP-2 μ2 subunit. Using specific inhibitors and dominant-negative mutants, we establish that this effect was mediated by activation of the adaptor associated kinase 1 /PKC-ζ isoform. Expression of the AP-2 μ2 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 α-subunit, and this effect requires phosphorylation of the AP-2 μ2 subunit. We conclude that phosphorylation of AP-2 μ2 subunit is essential for Na +,K+-ATPase endocytosis in response to a variety of signals, such as dopamine or reactive oxygen species.

Original languageEnglish (US)
Pages (from-to)127-132
Number of pages6
JournalAmerican journal of respiratory cell and molecular biology
Volume35
Issue number1
DOIs
StatePublished - Jul 2006

Keywords

  • Clathrin
  • Dopamine
  • Hypoxia
  • Kidney tubule cells
  • Lung alveolar cells

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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