Reference - Detail
|Author||Hollopeter G, Lange JJ, Zhang Y, Vu TN, Gu M, Ailion M, Lambie EJ, Slaughter BD, Unruh JR, Florens L, Jorgensen EM.|
|Title||The membrane-associated proteins FCHo and SGIP are allosteric activators of the AP2 clathrin adaptor complex.|
The AP2 clathrin adaptor complex links protein cargo to the endocytic machinery but it is unclear how AP2 is activated on the plasma membrane. Here we demonstrate that the membrane-associated proteins FCHo and SGIP1 convert AP2 into an open, active conformation. We screened for Caenorhabditis elegans mutants that phenocopy the loss of AP2 subunits and found that AP2 remains inactive in fcho-1 mutants. A subsequent screen for bypass suppressors of fcho-1 nulls identified 71 compensatory mutations in all four AP2 subunits. Using a protease-sensitivity assay we show that these mutations restore the open conformation in vivo. The domain of FCHo that induces this rearrangement is not the F-BAR domain or the µ-homology domain, but rather is an uncharacterized 90 amino acid motif, found in both FCHo and SGIP proteins, that directly binds AP2. Thus, these proteins stabilize nascent endocytic pits by exposing membrane and cargo binding sites on AP2.
|MeSH||Adaptor Protein Complex 2 / chemistry* Adaptor Protein Complex 2 / genetics Adaptor Protein Complex 2 / metabolism Allosteric Regulation Amino Acid Motifs Amino Acid Sequence Animals Biological Transport Caenorhabditis elegans / genetics* Caenorhabditis elegans / metabolism Caenorhabditis elegans Proteins / chemistry* Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism Carrier Proteins / chemistry* Carrier Proteins / genetics Carrier Proteins / metabolism Clathrin-Coated Vesicles / metabolism Clathrin-Coated Vesicles / ultrastructure Coated Pits, Cell-Membrane / metabolism Coated Pits, Cell-Membrane / ultrastructure Endocytosis / genetics* Gene Expression Regulation Membrane Proteins / chemistry* Membrane Proteins / genetics Membrane Proteins / metabolism Models, Molecular Molecular Sequence Data Mutation Protein Structure, Tertiary Protein Subunits / chemistry* Protein Subunits / genetics Protein Subunits / metabolism Sequence Alignment Signal Transduction|