This domain lies at the C-terminus of the clathrin-adaptor protein complex-3 beta-1 subunit. The AP-3 complex is associated with the Golgi region of the cell as well as with more peripheral structures. The AP-3 complex may be directly involved in trafficking to lysosomes or alternatively it may be involved in another pathway, but that mis-sorting in that pathway may indirectly lead to defects in pigment granules (PMID:10024875).
This domain lies at the C terminus of the clathrin-adaptor protein complex-3 beta-1 subunit. The AP-3 complex is associated with the Golgi region of the cell, as well as with more peripheral structures. Loss of functional AP-3 complex leads to defects in the function of lysosomes and lysosome-related organelles [ (PUBMED:10024875) ]. The AP-3 complex seems to be involved in the trafficking of lysosomal membrane proteins from endosomes [ (PUBMED:15051738) ].
Family alignment:
There are 1193 AP3B1_C domains in 1191 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing AP3B1_C domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with AP3B1_C domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing AP3B1_C domain in the selected taxonomic class.
Characterization of the adaptor-related protein complex, AP-3.
J Cell Biol. 1997; 137: 835-45
Display abstract
We have recently shown that two proteins related to two of the adaptor subunitsof clathrincoated vesicles, p47 (mu3) and beta-NAP (beta3B), are part of anadaptor-like complex not associated with clathrin (Simpson, F., N.A. Bright, M.A.West, L.S. Newman, R.B. Darnell, and M.S. Robinson, 1996. J. Cell Biol.133:749-760). In the present study we have searched the EST database and haveidentified, cloned, and sequenced a ubiquitously expressed homologue of beta-NAP,beta3A, as well as homologues of the alpha/gamma and sigma adaptor subunits,delta and sigma3, which are also ubiquitously expressed. Antibodies raisedagainst recombinant delta and sigma3 show that they are the other two subunits ofthe adaptor-like complex. We are calling this complex AP-3, a name that has also been used for the neuronalspecific phosphoprotein AP180, but we feel that it is amore appropriate designation for an adaptor-related heterotetramer.Immunofluorescence using anti-delta antibodies reveals that the AP-3 complex isassociated with the Golgi region of the cell as well as with more peripheralstructures. These peripheral structures show only limited colocalization withendosomal markers and may correspond to a postTGN biosynthetic compartment. Thedelta subunit is closely related to the protein product of the Drosophila garnet gene, which when mutated results in reduced pigmentation of the eyes and othertissues. Because pigment granules are believed to be similar to lysosomes, thissuggests either that the AP-3 complex may be directly involved in trafficking to lysosomes or alternatively that it may be involved in another pathway, but thatmissorting in that pathway may indirectly lead to defects in pigment granules.
Links (links to other resources describing this domain)
