May modulate processing of the amyloid-beta precursor protein (APP) and hence formation of APP-beta. May enhance the activity of HIF1A in macrophages by inhibiting the activity of HIF1AN (By similarity). Binds to the cytoplasmic domain of amyloid protein (APP). Interacts with HIF1AN (via N-terminus) (By similarity). Interacts with NECAB3; seems to mediate the interaction between NECAB3 and HIF1AN (By similarity). Ubiquitous. Composed of an N-terminal domain, a middle phosphotyrosine-binding domain (PID/PTB) that mediates binding with the cytoplasmic domain of the amyloid-beta precursor protein, and two C-terminal PDZ domains thought to attach proteins to the plasma membrane.