Immunoelectron-microscopic localization of the 180 kD component of the neural cell adhesion molecule N-CAM in postsynaptic membranes

摘要: In order to investigate the expression of cell adhesion molecules in synapses, we have studied localization neural molecule N-CAM cerebellum and hippocampus adult mice by immunocytological immunochemical methods. Of three molecular components with relative masses (Mr) 120, 140, 180 kD, 120 is not detectable synaptosomal membranes, whereas 140 expressed on both pre- postsynaptic membranes restricted sites, 180-specific epitope densities. Specificity immunoreactivity indicated observation that antibodies L1 do label synaptic two major densities, actin erythrocyte spectrin, react structures. Interestingly, only subpopulations synapses intact tissue. Isolated synaptosomes, opened for unimpeded accessibility antibody hypoosmotic treatment, also reveal a partial 67% are labeled 180, while spectrin 95% 88% all respectively. does appear be differentially particular morphological type, but types hippocampus, except mossy fiber between basket Purkinje cells, which generally 180-negative. Since has been shown characteristic stabilized or stabilizing contacts, possibly its association cytoskeleton-membrane linker protein (Pollerberg et al.: J. Cell Biol. 101:1921-1929, '85; Nature 324:462-465, '86; Tissue Res. 250:227-236, '87), would like suggest plays an important role determining stability contacts state activity.