| First Author | Theos AC | Year | 2005 |
| Journal | Mol Biol Cell | Volume | 16 |
| Issue | 11 | Pages | 5356-72 |
| PubMed ID | 16162817 | Mgi Jnum | J:107110 |
| Mgi Id | MGI:3620308 | Doi | 10.1091/mbc.E05-07-0626 |
| Citation | Theos AC, et al. (2005) Functions of adaptor protein (AP)-3 and AP-1 in tyrosinase sorting from endosomes to melanosomes. Mol Biol Cell 16(11):5356-72 |
| abstractText | Specialized cells exploit adaptor protein complexes for unique post-Golgi sorting events, providing a unique model system to specify adaptor function. Here, we show that AP-3 and AP-1 function independently in sorting of the melanocyte-specific protein tyrosinase from endosomes to the melanosome, a specialized lysosome-related organelle distinguishable from lysosomes. AP-3 and AP-1 localize in melanocytes primarily to clathrin-coated buds on tubular early endosomes near melanosomes. Both adaptors recognize the tyrosinase dileucine-based melanosome sorting signal, and tyrosinase largely colocalizes with each adaptor on endosomes. In AP-3-deficient melanocytes, tyrosinase accumulates inappropriately in vacuolar and multivesicular endosomes. Nevertheless, a substantial fraction still accumulates on melanosomes, concomitant with increased association with endosomal AP-1. Our data indicate that AP-3 and AP-1 function in partially redundant pathways to transfer tyrosinase from distinct endosomal subdomains to melanosomes and that the AP-3 pathway ensures that tyrosinase averts entrapment on internal membranes of forming multivesicular bodies. |
