Sorting of integral membrane proteins at various stages of the endocytic and secretory pathways is mediated by vesicular trafficking between a variety of organelles. Two sorting signals are tyrosine-based and dileucine-based signals that interact with heterotetrameric adaptor protein complexes (AP-1 through AP-4), which are associated with the vesicle coats. These coatomers contain two large adaptin proteins (γ, α, δ, ε and β1, β2, β3, β4, respectively) that are noncovalently linked to one medium chain (µ1, µ2, µ3, or µ4) and one small chain (σ1, σ2, σ3, or σ4). The AP-1 and AP-3 complexes are involved in protein sorting from the TGN and endosomes, while AP-2 adaptor complexes are involved in clathrin-mediated endocytosis. In the AP-3 complex, adaptin δ contains an N-terminal "head" domain that has 25% identity with adaptins α and γ, while its C-terminal "hinge" and "ear" domains are two-fold larger and more divergent as compared to the same domains in adaptins α and γ. Adaptin δ is widely expressed and its mutation results in protein storage deficiencies within lysosomal-related organelles in platelets, melansomes, and synaptic vesicles.
This antibody is routinely tested by western blot analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.