Expression of death‐associated protein kinase and recruitment to the tumor necrosis factor signaling pathway following brief seizures

Death‐associated protein (DAP) kinase is calcium‐regulated and known to function downstream of death receptors, prompting us to examine its role in the mechanism of seizure‐induced neuronal death. Brief seizures were focally evoked in rats, eliciting neuronal death within the CA3 subfield of the hippocampus, and to a lesser extent, cortex. Western blotting confirmed expression of DAP kinase within hippocampus and cortex at the predicted weight of ∼160 kDa. Immunohistochemistry revealed seizures triggered a significant increase in numbers of DAP kinase‐expressing cells within CA3 and cortex, without affecting cell counts within seizure‐resistant CA2 or the dentate gyrus. Numbers of DAP kinase‐expressing cells were increased in relation to specific patterns of injury‐causing seizure activity, electrographically defined. Seizures caused an early increase in DAP kinase binding to actin, and association with calmodulin. Co‐immunoprecipitation studies also revealed seizures triggered binding of DAP kinase to the tumor necrosis factor receptor 1 and the Fas‐associated death domain protein, commensurate with caspase‐8 proteolysis. In contrast, within surviving fields of the hippocampus, DAP kinase interacted with the molecular chaperone 14–3−3. These data suggest DAP kinase is involved in the molecular pathways activated during seizure‐induced neuronal death.