of cell surface receptor expressed on macrophages and other phagocytes. Mast Cells ICAM3 is also found on mast cells, another type of leukocyte. Mast cells taken from human lungs and the HMC-1 line, a human mast cell line, both showed expression of ICAM3. ICAM3 helps mediate the adhesion of mast cells to the extracellular matrix. Interactions Dendritic and T Cell Binding Binding between ICAM3 and DC-SIGN, which takes place during initial interactions between T cells and dendritic cells, occurs with high affinity. This binding process is also calcium-dependent. Apoptosis CD14, a receptor expressed on the surface of phagocytes, can also bind ICAM3. Interactions between CD14 and altered ICAM3 molecules on apoptotic cells are believed to help promote phagocytosis of apoptotic cells. Integrins ICAM3 is a known ligand for LFA-1, an integrin expressed by leukocytes. To facilitate binding, the I domain of LFA-1 interacts with the ICAM3 protein’s first immunoglobulin domain. ICAM3 also binds the integrin αDβ2. Additional Interactions ICAM3 has been shown to interact with activated ERM proteins, including ezrin (EZR) and moesin, in T cells. See also Cluster of differentiation References Further reading External links Clusters of differentiation