During receptor-mediated endocytosis, AP2 complexes act as a bridge between the cargo membrane proteins and the clathrin coat by binding to sorting signals via the mu 2 subunit and to clathrin via the beta subunit. Here we show that binding of AP2 to sorting signals in vitro is regulated by phosphorylation of the mu 2 subunit of AP2. Phosphorylation of mu 2 enhances the binding affinity of AP2 for sorting motifs as much as 25-fold compared with dephosphorylated AP2. The recognition of sorting signals was not affected by the phosphorylation status of the alpha or beta 2 subunit, suggesting that phosphorylation of mu 2 is critical for regulation of AP2 binding to sorting signals. Phosphorylation of mu 2 occurs at a single threonine residue (Thr-156) and is mediated by the newly discovered adaptor-associated kinase, AAK1, which copurifies with AP2. We propose that phosphorylation of the AP2 mu 2 subunit by AAK1 ensures high affinity binding of AP2 to sorting signals of cargo membrane proteins during the initial steps of receptor-mediated endocytosis.
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http://purl.uniprot.org/cit... | rdfs:comment | During receptor-mediated endocytosis, AP2 complexes act as a bridge between the cargo membrane proteins and the clathrin coat by binding to sorting signals via the mu 2 subunit and to clathrin via the beta subunit. Here we show that binding of AP2 to sorting signals in vitro is regulated by phosphorylation of the mu 2 subunit of AP2. Phosphorylation of mu 2 enhances the binding affinity of AP2 for sorting motifs as much as 25-fold compared with dephosphorylated AP2. The recognition of sorting signals was not affected by the phosphorylation status of the alpha or beta 2 subunit, suggesting that phosphorylation of mu 2 is critical for regulation of AP2 binding to sorting signals. Phosphorylation of mu 2 occurs at a single threonine residue (Thr-156) and is mediated by the newly discovered adaptor-associated kinase, AAK1, which copurifies with AP2. We propose that phosphorylation of the AP2 mu 2 subunit by AAK1 ensures high affinity binding of AP2 to sorting signals of cargo membrane proteins during the initial steps of receptor-mediated endocytosis. | lld:uniprot |
http://purl.uniprot.org/cit... | skos:exactMatch | http://purl.uniprot.org/pub... | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:name | J. Cell Biol. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:author | von Figura K. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:author | Schmid S.L. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:author | Honing S. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:author | Ricotta D. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:author | Conner S.D. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:date | 2002 | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:pages | 791-795 | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:title | Phosphorylation of the AP2 mu subunit by AAK1 mediates high affinity binding to membrane protein sorting signals. | lld:uniprot |
http://purl.uniprot.org/cit... | uniprot:volume | 156 | lld:uniprot |
http://purl.uniprot.org/cit... | dc-term:identifier | doi:10.1083/jcb.200111068 | lld:uniprot |
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