Kinetic simulation of signal transduction system in hippocampal long-term potentiation with dynamic modeling of protein phosphatase 2A

Shinichi Kikuchi, Kenji Fujimoto, Noriyuki Kitagawa, Taro Fuchikawa, Michiko Abe, Kotaro Oka, Kohtaro Takei, Masaru Tomita

研究成果: Article査読

21 被引用数 (Scopus)

抄録

We modeled and analyzed a signal transduction system of long-term potentiation (LTP) in hippocampal post-synapse. Bhalla and Iyengar [Science 283(1999) 381] have developed a hippocampal LTP model. In the conventional model, the concentration of protein phosphatase 2A (PP2A) was fixed. However, it was reported that dynamic inactivation of PP2A was essential for LTP [J. Neurochem. 74 (2000) 807]. We introduced a dynamic modeling of PP2A; inactivation (phosphorylation) of PP2A by calcium/calmodulin-dependent protein kinase II (CaMKII) in the presence of calcium/calmodulin, self-activation (autodephosphorylation) of PP2A, and inactivation (dephosphorylation) of CaMKII by PP2A. This model includes complex feedback loops; both CaMKII and PP2A are autoactivated, while they inactivate each other. Moreover, we proposed an analysis strategy for model validation by applying the results of sensitivity analysis. In our system, calcineurin (CaN) played an essential role, rather than the activation of protein kinase C (PKC) as documented in the conventional model. From results of the analysis of our model, we found the following robustness as characteristics of bistability in our model: (1) PP2A reactions against calcium ion (Ca2+) perturbation; (2) PP2A inactivation against PP2A increase; (3) protein phosphatase 1 (PP1) activation against PF2A increase; and (4) PP2A reactions against PP2A initial concentration. These properties facilitated LTP induction in our system. We showed that another mechanism could introduce bistable behavior by adding dynamic reactions of PP2A.

本文言語English
ページ(範囲)1389-1398
ページ数10
ジャーナルNeural Networks
16
9
DOI
出版ステータスPublished - 2003 11

ASJC Scopus subject areas

  • 認知神経科学
  • 人工知能

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