InterPro domain: IPR017104

Adaptor protein complex AP-2 has a role in clathrin-mediated endocytosis and intracellular transport [ 1 ]. AP-2 links clathrin to membrane lipids and transmembrane cargoes at the vesicle budding site [ 2 ]. It consists of two large subunits termed adaptins (alpha and beta subunits), a medium-sized one (mu), and a small one (sigma). It is thought to act in cargo selection by interaction with selection motifs encoded in the cytoplasmic tails of cargo molecules. The N-terminal domains of the adaptins, together with the mu and sigma subunits, constitute the 'head' of the adaptor, which interacts with plasma membrane lipids and cargoes. AP-2 plays a role in the recycling of synaptic vesicle membranes from the presynaptic surface [ 3 ].

This family represents the alpha subunit of adaptor protein complex AP-2.

1. The AP-2 complex is required for proper temporal and spatial dynamics of endocytic patches in fission yeast. Mol. Microbiol. 100, 409-24
2. Review series: From uncertain beginnings: initiation mechanisms of clathrin-mediated endocytosis. J. Cell Biol. 203, 717-25
3. Molecular mechanisms of presynaptic membrane retrieval and synaptic vesicle reformation. Neuron 85, 484-96