Induces susceptibility to atherosclerosis By similarity. Cell adhesion molecule which is required for leukocyte transendothelial migration (TEM) under most inflammatory conditions. Tyr-690 plays a critical role in TEM and is required for efficient trafficking of PECAM1 to and from the lateral border recycling compartment (LBRC) and is also essential for the LBRC membrane to be targeted around migrating leukocytes. Prevents phagocyte ingestion of closely apposed viable cells by transmitting 'detachment' signals, and changes function on apoptosis, promoting tethering of dying cells to phagocytes (the encounter of a viable cell with a phagocyte via the homophilic interaction of PECAM1 on both cell surfaces leads to the viable cell's active repulsion from the phagocyte.Garnacho C, et al. (2008) Blood 111, 3024-33. Udell CM, et al. (2006) J Biol Chem 281, 20949-57 . O'Brien CD, Cao G, Makrigiannakis A, DeLisser HM (2004)Am J Physiol Cell Physiol 287, C1103-13.