Junctional adhesion molecules (JAMs) are endothelial and epithelial adhesion molecules involved in the recruitment of circulating leukocytes to inflammatory sites. JAML (Junctional adhesion molecule-like), also known as AMICA1 (Adhesion molecule interacting with CXADR antigen 1), a protein related to the JAM family, is restricted to leukocytes and promotes their adhesion to endothelial cells. It contains 2 extracellular immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic tail involved in activation signaling. Monocytic JAML/AMICA1 plays a critical role in regulating monocyte transendothelial migration (TEM) probably via binding to the endothelial coxsackie and adenovirus receptor (CAR) and other tight junction-associated adhesive molecules. The Expression of JAML/AMICA1 is restricted to the hematopoietic tissues with the exception of liver. JAML may function in transmigration of leukocytes through epithelial and endothelial tissues. Expressed at the plasma membrane of polymorphonuclear leukocytes, JAML/AMICA1 also enhances myeloid leukemia cell adhesion to endothelial cells.