| First Author | Festoff BW | Year | 1991 |
| Journal | J Cell Physiol | Volume | 147 |
| Issue | 1 | Pages | 76-86 |
| PubMed ID | 2037625 | Mgi Jnum | J:161338 |
| Mgi Id | MGI:4458005 | Doi | 10.1002/jcp.1041470111 |
| Citation | Festoff BW, et al. (1991) Plasminogen activators and inhibitors in the neuromuscular system: III. The serpin protease nexin I is synthesized by muscle and localized at neuromuscular synapses. J Cell Physiol 147(1):76-86 |
| abstractText | Recent studies suggest that the nature of events leading to the formation, maintenance, and elimination of synapses may be regulated by cascade-type, locally expressed proteases and protease inhibitors acting on adhesive extracellular matrix components. We have identified a molecule in conditioned medium of murine skeletal muscle cells that in molecular weight, target protease inhibition, heparin-binding and cross-reactivity with authenic antisera is similar to the human serine proteinase inhibitor, protease nexin I. Protease nexin I is a 43-50 kDa glycoprotein of the serpin superfamily (arg-serpin class). Purified anti-protease nexin I antibody (anti-47 kDa) stains adult mouse skeletal muscle in discrete foci that precisely superimpose on synaptic neuromuscular junctions. Protease nexin I appears in patches on surfaces of cultured mouse skeletal myotubes, but not on myoblasts. These patches co-localize with acetylcholine receptor clusters and acetylcholinesterase staining during cellular maturation in culture. Evidence that protease nexin I is a synaptic, extracellular antigen is particularly intriguing since it has been shown to be identical, in structure and activity, with a factor released by glial cells, called glia-derived nexin that stimulates mouse neuroblastoma cell neurite outgrowth and inhibits granule cell migration. Protease nexin I inhibits both tumor cell and myoblast plasminogen activator-mediated destruction of extracellular matrix. Thus, such observations as presented in this report provide further evidence for involvement of cascade proteolytic systems, and their post-translational regulation by specific serpins, in the remodeling that occurs in synapse formation and elimination. |
