TETANUS TOXIN-SENSITIVE VAMP-RELATED PROTEINS ARE PRESENT IN MURINE MACROPHAGES

The light chain of tetanus neurotoxin (TeTx) is a zinc endopeptidase s pecific for VAMP/synaptobrevin (VAMP), a 120-amino-acid integral prote in previously described in the small synaptic vesicles of neuronal cel ls. TeTx has been shown to be active also on nonneuronal cells. By SDS -PAGE and quantitative immunoblotting on proteins derived from murine macrophages (M phi) exposed to TeTx, we have shown that: (1) VAMP-rela ted proteins are also present in M phi and (2) such proteins are sensi tive to TeTx proteolytic cleavage. The demonstration that TeTx acts on VAMP-related proteins also in M phi offers a new and useful tool for molecular studies on M phi exocytosis. (C) 1996 Academic Press, Inc.