May be involved in regulating membrane trafficking in the endosomal pathway. Overexpression induces endosome aggregation. Required to target TOM1 to endosomes. Interacts with the C-terminus of TOM1. Does not interact with TOM1L1 or TOM1L2. Localized to early endosomes. Membrane-associated, probably via its association with phosphatidylinositol 3-phosphate (PI3P). Widely expressed. Highly expressed in kidney, placenta and lung. Expressed at intermediate level in heart, brain, skeletal muscle, spleen and liver. Weakly expressed in colon, thymus and peripheral blood lymphocytes. The FYVE-type zinc finger is necessary and sufficient for its localization into early endosomes and mediates the association with PI3P. Extended N-terminus.