Abstract
Laminin was localized in cultured mouse C1300 neuroblastoma cells by applying the peroxidase-antiperoxidase technique in preembedding electron microscopy. The results were compared to those obtained by indirect immunofluorescence and by the colloidal gold second antibody method on Epon-embedded ultrathin sections. Laminin was found in the cell membranes and within the rough endoplasmic reticulum as well as in intracytoplasmic vacuoles. Plasma membranes of the neuroblastoma cells showed a patchy localization of laminin that was apparently involved in cell-to-substrate attachment and in gap junction-like intercellular connections. Under normal conditions, the Golgi cisternae contained no laminin. Pretreatment of cells with micromolar concentrations of monensin, however, lead to an accumulation of laminin within the Golgi cisternae. These results support a role for laminin as an adhesion protein in cultured neuroblastoma cells and indicate that laminin is transported through the Golgi complex.