PMID: 26779610
De Franceschi N, Arjonen A, Elkhatib N, Denessiouk K, Wrobel AG, Wilson TA, Pouwels J, Montagnac G, Owen DJ, Ivaska J
Selective integrin endocytosis is driven by interactions between the integrin alpha-chain and AP2.
Nat Struct Mol Biol. 2016 Jan 18. doi: 10.1038/nsmb.3161.
Integrins are heterodimeric cell-surface adhesion molecules comprising one of 18 possible alpha-chains and one of eight possible beta-chains. They control a range of cell functions in a matrix- and ligand-specific manner. Integrins can be internalized by clathrin-mediated endocytosis (CME) through beta subunit-based motifs found in all integrin heterodimers. However, whether specific integrin heterodimers can be selectively endocytosed was unknown. Here, we found that a subset of alpha subunits contain an evolutionarily conserved and functional YxxPhi motif directing integrins to selective internalization by the most abundant endocytic clathrin adaptor, AP2. We determined the structure of the human integrin alpha4-tail motif in complex with the AP2 C-mu2 subunit and confirmed the interaction by isothermal titration calorimetry. Mutagenesis of the motif impaired selective heterodimer endocytosis and attenuated integrin-mediated cell migration. We propose that integrins evolved to enable selective integrin-receptor turnover in response to changing matrix conditions.