Adaptor Related Protein Complex 4 Mu 1 (AP4m1)

AP4m1 encodes a subunit of the heterotetrameric AP-4 complex. The encoded protein belongs to the adaptor complexes medium subunits family. This AP-4 complex is involved in the recognition and sorting of cargo proteins with tyrosine-based motifs from the trans-golgi network to the endosomal-lysosomal system.

The predicted 434-amino acid mu-ARP2 sequence is 31% identical to those of mu-adaptins, the medium chains of the clathrin coat adaptor complexes. Wang and Kilimann (1997) showed by Northern blot analysis that the mu-ARP2 gene was expressed in all tissues examined, with the highest level in testis. They speculated that mu-ARP2 is a subunit of a novel type of clathrin- or non-clathrin-associated protein coat involved in membrane trafficking.