Plays a central role in tight junction maintenance via the complex formed with ARHGAP17, which acts by regulating the uptake of polarity proteins at tight junctions. Appears to regulate endothelial cell migration and tube formation. May also play a role in the assembly of endothelial cell-cell junctions (By similarity). Component of a complex whose core is composed of ARHGAP17, AMOT, PALS1, PATJ and PARD3/PAR3. Interacts with MAGI1 and angiostatin (By similarity). Localized on the cell surface. May act as a transmembrane protein (By similarity). Expressed in brain, skeletal muscle and placenta. The angiostatin binding domain (850-1047) allows the binding to angiostatin. The coiled coil domain interacts directly with the BAR domain of ARHGAP17. Polyubiquitinated by NEDD4, NEDD4L and ITCH, leading to proteasomal degradation. 'Motus' means 'motility' in Latin. Belongs to the angiomotin family.