Death-associated protein kinase expression in human temporal lobe epilepsy

Area of Science:

• Neuroscience
• Molecular Biology
• Pathology

Background:

• Refractory temporal lobe epilepsy is associated with progressive hippocampal atrophy.
• Programmed cell death pathways, including those involving death receptors, are implicated in neuronal loss.
• Death-Associated Protein (DAP) kinase is a calcium/calmodulin-activated kinase involved in apoptosis.

Purpose of the Study:

• To investigate the expression, localization, and interactions of DAP kinase in human temporal lobe epilepsy.
• To determine if DAP kinase plays a role in seizure-induced neuronal death.

Main Methods:

• Analysis of hippocampal resections from epilepsy patients (n=10) and controls (n=6).
• Assessed DAP kinase and DAP kinase-interacting protein 1 (DIP-1) expression and localization using biochemical and immunohistochemical techniques.
• Examined protein interactions using coimmunoprecipitation.

Main Results:

• Significantly increased expression and phosphorylation of DAP kinase in epilepsy brain tissue compared to controls.
• DAP kinase and DIP-1 shifted from mitochondrial localization to increased cytoplasmic and microsomal fractions in epilepsy samples.
• Enhanced binding of DAP kinase to calmodulin, DIP-1, and FADD was observed in epilepsy samples.
• DAP kinase was coexpressed with DIP-1 in neurons.

Conclusions:

• This study provides the first evidence of DAP kinase and DIP-1 in the human brain.
• DAP kinase is upregulated and altered in its cellular localization and interactions in temporal lobe epilepsy.
• DAP kinase emerges as a novel molecular regulator potentially involved in neuronal death in epilepsy.