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A Role for Adaptor Protein‐3 Complex in the Organization of the Endocytic Pathway in Dictyostelium
Author(s) -
Charette Steve J.,
Mercanti Valentina,
Letourneur François,
Bennett Nelly,
Cosson Pierre
Publication year - 2006
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2006.00478.x
Subject(s) - endocytic cycle , endosome , microbiology and biotechnology , biology , clathrin , dictyostelium discoideum , signal transducing adaptor protein , dictyostelium , endomembrane system , golgi apparatus , clathrin adaptor proteins , endocytosis , signal transduction , cell , endoplasmic reticulum , biochemistry , intracellular , gene
Dictyostelium discoideum cells continuously internalize extracellular material, which accumulates in well‐characterized endocytic vacuoles. In this study, we describe a new endocytic compartment identified by the presence of a specific marker, the p25 protein. This compartment presents features reminiscent of mammalian recycling endosomes: it is localized in the pericentrosomal region but distinct from the Golgi apparatus. It specifically contains surface proteins that are continuously endocytosed but rapidly recycled to the cell surface and thus absent from maturing endocytic compartments. We evaluated the importance of each clathrin‐associated adaptor complex in establishing a compartmentalized endocytic system by studying the phenotype of the corresponding mutants. In knockout cells for μ3, a subunit of the AP‐3 clathrin‐associated complex, membrane proteins normally restricted to p25‐positive endosomes were mislocalized to late endocytic compartments. Our results suggest that AP‐3 plays an essential role in the compartmentalization of the endocytic pathway in Dictyostelium .