FIGURE 5.

PLA₁ activity was induced at the tips of processes by NGF treatment and it co-localized with mAb#15 antigen. A, live PC12 cells that were treated with NGF for 48 h were stained with fluorogenic substrate for PLA₁ activity (PED-A1 in green; left) or for PLA₂ activity (PC-A2 in green; right). Bar, 40 μm. B, major activity of PLA₁ was localized on the plasma membrane at the very tips of processes (thick arrow) and weaker activities were detected at vesicular structures inside the tips (thin arrows). Bar, 10 μm. C, after treatment with NGF for 30 h, live PC12 cells were stained with PED-A1. Although the activity was weaker than that of later time points, PLA₁ activities were detected at the very tips of filopodia (arrows). Bar, 25 μm. D, time course examinations of PLA₁ activity (top lane) and of mAb#15 immunoreactivity (bottom lane) after NGF treatment. Activities are shown in green. Bar, 40 μm. E, simultaneous staining of PLA₁ activity and mAb#15 antigen with fixed PC12 cells (green, PED-A1; red, mAb#15; yellow, the merge of PED-A1 and mAb#15). Bar, 10 μm.