The adaptor protein (AP) 3 adaptor complex has been implicated in the transport of lysosomal membrane proteins, but its precise site of action has remained controversial. Here, we show by immuno-electron microscopy that AP-3 is associated with budding profiles evolving from a tubular endosomal compartment that also exhibits budding profiles positive for AP-1. AP-3 colocalizes with clathrin, but to a lesser extent than does AP-1. The AP-3– and AP-1–bearing tubular compartments contain endocytosed transferrin, transferrin receptor, asialoglycoprotein receptor, and low amounts of the cation-independent mannose 6-phosphate receptor and the lysosome-associated membrane proteins (LAMPs) 1 and 2. Quantitative analysis revealed that of these distinct cargo proteins, only LAMP-1 and LAMP-2 are concentrated in the AP-3–positive membrane domains. Moreover, recycling of endocytosed LAMP-1 and CD63 back to the cell surface is greatly increased in AP-3–deficient cells. Based on these data, we propose that AP-3 defines a novel pathway by which lysosomal membrane proteins are transported from tubular sorting endosomes to lysosomes.
Localization of the AP-3 adaptor complex defines a novel endosomal exit site for lysosomal membrane proteins
A. Peden,V. Oorschot,B. A. Hesser,Cary D. Austin,R. Scheller,J. Klumperman
Published 2004 in Journal of Cell Biology
ABSTRACT
PUBLICATION RECORD
- Publication year
2004
- Venue
Journal of Cell Biology
- Publication date
2004-03-29
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- ap-1 adaptor complex
A related adaptor protein complex associated with endosomal membrane sorting domains.
Aliases: AP-1
- ap-3 adaptor complex
A membrane-associated adaptor protein complex involved in cargo sorting at endosomal membranes.
Aliases: AP-3
- ap-3-deficient cells
Cells lacking functional AP-3 adaptor complex activity.
Aliases: AP-3 deficient cells
- cd63
A tetraspanin-like lysosomal membrane protein used as a cargo marker.
- clathrin
A coat protein that assembles on membrane buds during vesicle formation.
- lamp-1
Lysosome-associated membrane protein 1, a lysosomal membrane protein used as a cargo marker.
Aliases: lysosomal-associated membrane protein 1
- lamp-2
Lysosome-associated membrane protein 2, a lysosomal membrane protein used as a cargo marker.
Aliases: lysosomal-associated membrane protein 2
- lysosomal membrane proteins
Membrane proteins destined for or resident in lysosomes.
Aliases: lysosome-associated membrane proteins
- tubular endosomal compartment
A tubular sorting endosome compartment involved in endosomal cargo trafficking.
Aliases: tubular sorting endosome, tubular endosome
REFERENCES
Showing 1-61 of 61 references · Page 1 of 1