FIGURE 9:

Model for role of AP-3, AP-1 and BLOC-1 in transport of OCA2 from endosomes to melanosomes. Shown is a model based on a related model from Delevoye et al. (2009) and the data from this article. In vacuolar endosomes, OCA2 encounters either AP-1 or AP-3, and either is sufficient to target OCA2 to melanosome-bound transport carriers that emerge from these domains. BLOC-1 also functions in an as-yet-unknown capacity during this step. From the transport carriers, binding to AP-3 is required to effect a subsequent transport step that results in stable association with melanosomes.