グルタミン酸誘導的な細胞死を調節するタンパク質複合体の解析

2014 Fiscal Year Annual Research Report

• Project/Area Number: 25830047
• Research Institution: The University of Tokyo
• Principal Investigator: 王 旻 東京大学, 教養学部, 助教 (10616329)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: Receptor / Cell Death / Neurotransmitter / Glutamate / AMPA

Outline of Annual Research Achievements

The accumulation of glutamate, which occurs immediately after ischemia, results in excessive stimulation of glutamate receptors leading to neurotoxicity. Thus, suppressing glutamate receptor function has gained significant interest towards the therapeutic treatment of ischemic stroke. However, clinical application of glutamate receptor antagonists in stroke treatment has failed since these treatments suppress postsynaptic glutamate response that is needed for normal brain function.

In the first year (FY2013), we used GST-fusion proteins encoding fragments of GluR2 subunit of AMPA receptor to affinity pull down GAPDH. We have successfully delineated the region (Y142-K172) of GluR2 involved in the interaction with GAPDH. The presence of peptide encoding Y142-K172 region of GluR2 is able to competitively interfere with the protein complex, which further confirms the association between GluR2 and GAPDH. Moreover, AMPAR/GAPDH protein complex is formed through a direct interaction by performing in vitro binding assays. Together, these data suggest that GAPDH formed a direct protein-protein interaction with the GluR2 subunit through the Y142-K172 region.

In the past year (FY2014), We have found that AMPAR activation facilitates the complex formation and results in an endocytosis-dependent translocation of the complex to the nucleus, whereby GAPDH dissociates from the AMPAR and binds to nuclear p53 and activates the p53-dependent cell death pathway. Disrupting either the GAPDH-GluR2 or GAPDH-p53 interaction protects against AMPAR-induced cell death.