The alternate AP-1 adaptor subunit Apm2 interacts with the Mil1 regulatory protein and confers differential cargo sorting

• DOI: 10.1091/mbc.e15-09-0621
• Publication Date: 2015-12-11T03:28:53Z
• Authors: Shawn T. Whitfield; Helen E. Burston; Björn D. M. Bean; Nandini Raghuram; Lymarie Maldonado...; Michael Davey; Beverly Wendland; Elizabeth Conibear
• Keywords: Clathrin adaptor proteins; Transport protein; Retromer

Heterotetrameric adaptor protein complexes are important mediators of cargo sorting in clathrin-coated vesicles. The cell type-specific expression alternate μ chains creates distinct forms AP-1 with altered sorting, but how these subunits confer differential function is unclear. Whereas some studies suggest the specify localization to different cellular compartments, others find that two present same vesicle recognize cargo. Yeast have AP-1, which differ only chain. Here we show variant chain Apm2 confers cargo-sorting functions. Loss Apm2, not Apm1, increases surface levels v-SNARE Snc1. However, unable replace Apm1 Chs3, requires a dileucine motif recognized by γ/σ common both complexes. and colocalize at Golgi/early endosomes, suggesting they do associate compartments. We identified novel, conserved regulatory required for Apm2-dependent events. Mil1 predicted lipase binds contributes its membrane recruitment. Interactions specific factors may provide general mechanism diversify functional repertoire clathrin