Reduced CaM Kinase II and CaM Kinase IV Activities Underlie Cognitive Deficits in NCKX2 Heterozygous Mice

Shigeki Moriguchi, Satomi Kita, Yasushi Yabuki, Ryo Inagaki, Hisanao Izumi, Yuzuru Sasaki, Hideaki Tagashira, Kyoji Horie, Junji Takeda, Takahiro Iwamoto, Kohji Fukunaga

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Among five members of the K+-dependent Na+/Ca2+ exchanger (NCKX) family (NCKX1–5), only NCKX2 is highly expressed in mouse brain. NCKX2 in plasma membranes mediates cytosolic calcium excretion through electrogenic exchange of 4 Na+ for 1 Ca2+ and 1 K+. Here, we observed significantly decreased levels of NCKX2 protein and mRNA in the CA1 region of APP23 mice, a model of Alzheimer’s disease. We also found that, like APP23 mice, heterozygous NCKX2-mutant mice exhibit mildly impaired hippocampal LTP and memory acquisition, the latter based on novel object recognition and passive avoidance tasks. When we addressed underlying mechanisms, we found that both CaMKII autophosphorylation and CaMKIV phosphorylation significantly decreased in CA1 regions of NCKX2+/− relative to control mice. Likewise, phosphorylation of GluA1 (Ser-831) and CREB (Ser-133), respective downstream targets of CaMKII and CaMKIV, also significantly decreased in the CA1 region. BDNF protein and mRNA levels significantly decreased in CA1 of NCKX2+/− relative to control mice. Finally, CaN activity increased in CA1 of NCKX2+/− mice. Our findings suggest that like APP23 mice, NCKX2+/− mice may exhibit impaired learning and hippocampal LTP due to decreased CaM kinase II and CaM kinase IV activities.

Original languageEnglish
Pages (from-to)3889-3900
Number of pages12
JournalMolecular Neurobiology
Volume55
Issue number5
DOIs
Publication statusPublished - 2018 May 1

Keywords

  • Calcium/calmodulin-dependent protein kinase II
  • Cognition
  • Hippocampus
  • K-dependent Na/Ca exchangers
  • Long-term potentiation

ASJC Scopus subject areas

  • Neurology
  • Cellular and Molecular Neuroscience

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