Still more complexity in mammalian basement membranes

AC Erickson, JR Couchman - Journal of Histochemistry & …, 2000 - journals.sagepub.com
AC Erickson, JR Couchman
Journal of Histochemistry & Cytochemistry, 2000journals.sagepub.com
At the epithelial/mesenchymal interface of most tissues lies the basement membrane (BM).
These thin sheets of highly specialized extracellular matrix vary in composition in a tissue-
specific manner, and during development and repair. For about two decades it has been
apparent that all BMs contain laminins, entactin-1/nidogen-1, Type IV collagen, and
proteoglycans. However, within the past few years this complexity has increased as new
components are described. The entactin/nidogen (E/N) family has expanded with the recent …
At the epithelial/mesenchymal interface of most tissues lies the basement membrane (BM). These thin sheets of highly specialized extracellular matrix vary in composition in a tissue-specific manner, and during development and repair. For about two decades it has been apparent that all BMs contain laminins, entactin-1/nidogen-1, Type IV collagen, and proteoglycans. However, within the past few years this complexity has increased as new components are described. The entactin/nidogen (E/N) family has expanded with the recent description of a new isoform, E/N-2/osteonidogen. Agrin and Type XVIII collagen have been reclassified as heparan sulfate proteoglycans (HSPGs), expanding the repertoire of HSPGs in the BM. The laminin family has become more diverse as new α-chains have been characterized, increasing the number of laminin isoforms. Interactions between BM components are now appreciated to be regulated through multiple, mostly domain-specific mechanisms. Understanding the functions of individual BM components and their assembly into macromolecular complexes is a considerable challenge that may increase as further BM and cell surface ligands are discovered for these proteins.
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