Anti-DAPK1 polyclonal antibody

Immediately following ischemia, glutamate accumulates in the extracellular space and results in extensive stimulation of its receptors including N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors. A large amount of Ca2+ influx directly through the receptor-gated ion channels which leads to Ca2+ overload and triggers several downstream lethal reactions. As a result, cell dies via apoptosis or necrosis, or both. Death-associated protein kinase 1 (DAPK1) physically and functionally interacts with the NMDA receptor GluN2B subunit at extra-synaptic sites and this interaction acts as a central mediator for stroke damage. The goal of this study is to explore an effective strategy in the treatment of stroke with a molecular genetic manipulation to interrupt DAPK1-GluN2B interaction. We generated a mutant strain of mice with the conditional deletion of GluN2B C-terminal tail consisting of amino acids 886-1269 in the forebrain excitatory neurons (the GluN2B mutant mice) and tested the protective effects of this mutation in stroke damages. GluN2B mutation effectively disrupted the DAPK1-GluN2B interaction and inhibited extra-synaptic NMDA receptor currents without affecting synaptic NMDA receptor channel activity in the central neurons. GluN2B mutation protected against stroke damages both in vitro and in vivo and hence improved behavioral performance. Disruption of the DAPK1-GluN2B interaction is therapeutically effective against stroke damages.

The death-associated protein kinase 1 (DAPK1) is a potent mediator of neuronal cell death. Here, we find that DAPK1 also functions in synaptic plasticity by regulating the Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII). CaMKII and T286 autophosphorylation are required for both long-term potentiation (LTP) and depression (LTD), two opposing forms of synaptic plasticity underlying learning, memory, and cognition. T286-autophosphorylation induces CaMKII binding to the NMDA receptor (NMDAR) subunit GluN2B, which mediates CaMKII synaptic accumulation during LTP. We find that the LTP specificity of CaMKII synaptic accumulation is due to its LTD-specific suppression by calcineurin (CaN)-dependent DAPK1 activation, which in turn blocks CaMKII binding to GluN2B. This suppression is enabled by competitive DAPK1 versus CaMKII binding to GluN2B. Negative regulation of DAPK1/GluN2B binding by Ca2+/CaM results in synaptic DAPK1 removal during LTP but retention during LTD. A pharmacogenetic approach showed that suppression of CaMKII/GluN2B binding is a DAPK1 function required for LTD.