Clathrin-mediated endocytosis depends upon the coordinated assembly of a large number of discrete clathrin coat components to couple cargo selection with rapid internalization from the cell surface. Accordingly, the heterotetrameric AP-2 adaptor complex binds not only to clathrin and select cargo molecules, but also to an extensive family of endocytic accessory factors and alternate sorting adaptors. Physical associations between accessory proteins and AP-2 occur primarily through DP(F/W) or FXDXF motifs, which engage an interaction surface positioned on the C-terminal platform subdomain of the independently folded α subunit appendage. Here, we find that the WXX(F/W)X(D/E) interaction motif found in several endocytic proteins, including synaptojanin 1, stonin 2, AAK1, GAK, and NE-CAP1, binds a second interaction site on the bilobal α appendage, located on the N-terminal β sandwich subdomain. Both α appendage binding sites can be engaged synchronously, and our data reveal that varied assemblies of interaction motifs with different affinities for two sites upon the α appendage can provide a mechanism for temporal ordering of endocytic accessory proteins during clathrin-mediated endocytosis.

Original languageEnglish
Pages (from-to)46191-46203
Number of pages13
JournalJournal of Biological Chemistry
Issue number44
StatePublished - Oct 29 2004


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