Endocytosis of Na+,K+-ATPase molecules in response to G protein- coupled receptor stimulation requires activation of class I(A) phosphoinositide-3 kinase (PI3K-I(A)) in a protein kinase C-dependent manner. In this paper, we report that PI3K-I(A), through its p85α subunit-SH3 domain, binds to a proline-rich region in the Na+,K+-ATPase catalytic α subunit. This interaction is enhanced by protein kinase C-dependent phosphorylation of a serine residue that flanks the proline-rich motif in the Na+, K+-ATPase α subunit and results in increased PI3K-I(A) activity, an effect necessary for adaptor protein 2 binding and clathrin recruitment. Thus, Ser-phosphorylation of the Na+,K+-ATPase catalytic subunit serves as an anchor signal for regulating the location of PI3K-I(A) and its activation during Na+, K+-ATPase endocytosis in response to G protein-coupled receptor signals.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 6 2000|
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