Fig. 1. Syn1A and munc-18-1 are not immunodetected in epithelial cell lines. Total tissue and cell extracts were prepared from human cerebellum (lane 1), human colon carcinoma derived Caco-2 cells (lane 2), human meningioma (lane 3), canine brain cortex (lane 4), MDCK cells (lane 5) and canine liver (lane 6). Equal amounts of protein were separated on 10% SDS-polyacrylamide gels, transferred onto nitrocellulose and probed with an anti-syn1A monoclonal antibody (Syn1; A), a polyclonal antibody raised against a synthetic peptide of the rat munc-18-1 (Munc-18-1; B) sequence and an anti-munc-18-2 antiserum (Munc-18-2; C). Endogenous syn 1 and munc18-1 could be detected in the human and canine neuronal tissues, whereas the more widespread munc-18-2 protein was immunodetected in all tissues examined with the exception of human meningioma. The positions of molecular mass markers are shown.