Seizure activity induces PIM-1 expression in brain.

We recently identified KID-1, a previously undescribed protein kinase induced by depolarization in PC12 cells and brain (Feldman et al., 1998). KID-1 shares a high degree of sequence homology with PIM-1, a proto-oncogene previously reported to be expressed in hematopoietic and germ cells. We examined PIM-1 expression in stimulated PC12 cells, brains of kainic acid-treated rats, and a number of tissues from untreated rats. We now report that forskolin, but not depolarization or growth factors, induces PIM-1 expression in PC12 cells. PIM-1 is an immediate early gene induced in response to forskolin stimulation. We detect PIM-1 mRNA in a number of unstimulated tissues and at low levels in unstimulated brain. Systemic kainic acid administration to adult rats induces PIM-1 expression in the dentate gyrus region of the hippocampus.