Figure 1.

Expression of tPA protein localizes to dendrites and synapses. A, Western blot of rat hippocampal homogenate probed with an affinity-purified anti-tPA antibody recognizes a single band of ∼68 kDa (arrow). Molecular weight markers shown on the left. B, tPA immunoreactivity (red) is detected in the cell body and distributed in puncta on hippocampal neurons in culture. This distribution is similar to that of synaptophysin (green). C, Images in B overlaid with each other and on the bright-field phase image showing dendritic distribution of tPA. Yellow puncta indicate a colocalization of tPA with synaptophysin (arrows). Box indicates an area of the cell shown at higher magnification in the right panel showing tPA protein also distributed in small puncta throughout the dendrite (arrowheads). Scale bars: B, C, left panel, 20 μm; C, right panel, 5 μm.