This gene encodes the mu-1 subunit of the scaffolding adapter protein complex AP-1 and is a member of the mu adaptin family. The AP-1 complex, which consists of 4 subunits (mu-adaptin, beta-prime adaptin, gamma-adaptin, and the small chain adaptin), is one of the predominant coat proteins of membrane vesicles involved in eukaryotic post-Golgi trafficking. The AP-1 complex is located at the Golgi vesicle and links clathrin to receptors in coated vesicles. These vesicles are involved in endocytosis and Golgi processing. AP-1 complex subunit mu-1 and other mu-adaptins select cargo proteins bearing sequence-specific sorting motifs. [provided by RefSeq, Jul 2016]