Intercellular adhesion molecule-1 (ICAM-1) expression and cell signaling cascades

The collective interaction between cells is, in part, mediated by different families of adhesion molecules. Intercellular adhesion molecules (ICAMs) a re structurally related members of the immunoglobulin supergene family and are ligands for the beta 2 integrin molecules present on leukocytes. Of the five ICAMs identified, ICAM-1 is the most extensively studied. Although IC AM-1 is expressed constitutively at low levels on endothelial cells and on some lymphocytes and monocytes, its expression can be significantly increas ed in the presence of cytokines (TNF alpha, IL-1, IFN gamma) and reactive o xygen species. Depending upon cell type, ICAM-1 participates in trafficking of inflammatory cells, in cell:cell interactions during antigen presentati on, in microbial pathogenesis, and in signal transduction through outside-i n signaling events. Again, depending upon cell type examined, ICAM-1 engage ment has been documented to activate specific kinases through phosphorylati on, resulting in transcription factor activation and increased cytokine pro duction, increased cell membrane protein expression, reactive oxygen specie s production, and cell proliferation. (C) 2000 Elsevier Science Inc.