The extracellular matrix does more than just blanket cells; it also provides informational cues which affect a variety of developmental and cellular maintenance activities. The constituents of the matrix provide the fabric for cell motility and cell shape as well as anchorage sites for bioactive factors which directly affect the cell's developmental pattern or mitotic activity. The influence of the extracellular matrix is controlled by the cell's responsiveness to these complex signals. The same matrix component, for example hyaluronic acid, can (...) have completely different effects depending on the cell's lineage and developmental history. The functional interaction between the extracellular matrix and specific cell surface receptors provides cues which affect the control of development and the maintenance and aging events that affect specific cells and tissues. (shrink)