AP4B1AP-4 complex subunit beta-1 is a protein that in humans is encoded by the AP4B1 gene.FunctionThe heterotetrameric adaptor protein complexes sort integral membrane proteins at various stages of the endocytic and secretory pathways. AP4 is composed of 2 large chains, beta-4 and epsilon-4, a medium chain, mu-4, and a small chain, sigma-4InteractionsAP4B1 has been shown to interact with AP4M1.Clinical relevanceAP4-complex-mediated trafficking plays a crucial role in brain development and functioning.