Synaptophysin 2, also known as Synaptoporin, is a component of the synaptic vesicle membrane and thought to play an important role in synaptic vesicle trafficking (Dai et al., 2003). It is highly homologous to Synaptophysin 1, yet differs in expression. Whereas Synaptophysin 1 is ubiquitiously expressed, Synaptophysin 2 is concentrated in the mossy fiber synapses of the hippocampus (Grabs et al., 1994, Singec et al., 2002). Anti-Synaptophysin 2 Western blot of rat hippocampal lysate showing specific labeling of the ~38k Synaptophysin2 protein.