Plays an essential role for cellular polarization, directed cell migration and modulating cell-cell contact. Interacts (via the C-terminus 4300-4400 AA) with ATN1 (PubMed:19131340). Interacts with RERE (PubMed:19131340). Expressed in many epithelial and some endothelial and smooth muscle cells. A PTB-like motif (DNXYH sequence) is required for the targeting to the leading edge. This motif represents a minimal protein-protein interaction core motif that is not regulated by tyrosine phosphorylation (By similarity). Undergoes proteolytic cleavage. The extracellular domain is cleaved off and the cytoplasmic domain (about 400 AA) shuttles to the nucleus.