BASAL LAMINA ASSEMBLY

From studies of the 'classical' components, models for the assembly an d structure of an idealized basal lamina have been developed. In parti cular, the evidence supports the concept of enmeshed collagen and lami nin polymers, in which nidogen/entactin acts as a bridge between these molecules and provides anchorage for diverse matrix components. Diffe rent basement membranes, however, possess different members of the bas ic basal lamina families, such as the newly described alpha 6(IV) coll agen, alpha 2 (merosin) laminin, and beta 3 laminin (in kalinin/nicein ) chains. Even though these members share homologous domains and seque nces, and are likely to share certain functions, they also possess uni que characteristics that are expected to provide for basal lamina hete rogeneity. A combination of genetic, recombinant and biochemical appro aches are now being applied to elucidate the special roles of both old and new components.