ABSTRACT
Most cells in multicellular organisms contact, on at least one of their surfaces, an intricate meshwork of interacting extracellular molecules that constitutes the extracellular matrix. The amount and type of extracellular matrix is highly variable, especially during development, and is tissue dependent (1). There is considerable evidence that the extracellular matrix has many structural and biological functions in tissues (Table 1). Much of the information on the biological activity of the extracellular matrix has come from in vitro studies with cells grown on purified matrices and on isolated components, and from the elucidation of the role of matrix molecules in diseases (2--4). The importance of the extracellular matix in development is further confirmed with the identification of various genetic diseases. Also, the biochemistry of these molecules is beginning to be understood at the structural level and active sites have been identified using fragments, antibodies, and synthetic peptides. Because of their important biological activities, some of these extracellular matrix molecules have the potential to be used therapeutically for tissue repair and possibly to control disease progression.
