Transient Fcho1/2Eps15/RAP-2 Nanoclusters Prime the AP-2 Clathrin Adaptor for Cargo Binding.
Ma, L., Umasankar, P.K., Wrobel, A.G., Lymar, A., McCoy, A.J., Holkar, S.S., Jha, A., Pradhan-Sundd, T., Watkins, S.C., Owen, D.J., Traub, L.M.(2016) Dev Cell 37: 428-443
- PubMed: 27237791 
- DOI: https://doi.org/10.1016/j.devcel.2016.05.003
- Primary Citation of Related Structures:  
5JP2 - PubMed Abstract: 
Clathrin-coated vesicles form by rapid assembly of discrete coat constituents into a cargo-sorting lattice. How the sequential phases of coat construction are choreographed is unclear, but transient protein-protein interactions mediated by short interaction motifs are pivotal. We show that arrayed Asp-Pro-Phe (DPF) motifs within the early-arriving endocytic pioneers Eps15/R are differentially decoded by other endocytic pioneers Fcho1/2 and AP-2. The structure of an Eps15/R⋅Fcho1 μ-homology domain complex reveals a spacing-dependent DPF triad, bound in a mechanistically distinct way from the mode of single DPF binding to AP-2. Using cells lacking FCHO1/2 and with Eps15 sequestered from the plasma membrane, we establish that without these two endocytic pioneers, AP-2 assemblies are fleeting and endocytosis stalls. Thus, distinct DPF-based codes within the unstructured Eps15/R C terminus direct the assembly of temporary Fcho1/2⋅Eps15/R⋅AP-2 ternary complexes to facilitate conformational activation of AP-2 by the Fcho1/2 interdomain linker to promote AP-2 cargo engagement.
Organizational Affiliation: 
Department of Cell Biology, University of Pittsburgh School of Medicine, 3500 Terrace Street, S312 BST, Pittsburgh, PA 15261, USA.