Belelovsky K, Elkobi A, Kaphzan H, Nairn A C, Rosenblum K
Center for Brain and Behaviour, Department of Neurobiology and Ethology, Faculty of Sciences, University of Haifa, Haifa 30905, Israel.
Eur J Neurosci. 2005 Nov;22(10):2560-8. doi: 10.1111/j.1460-9568.2005.04428.x.
In a variety of species memory consolidation following different learning paradigms has been shown to be dependent on protein synthesis. However, it is not known whether modulation of protein synthesis is a critical component of the consolidation process, nor is the identity of any protein(s) subject to translational regulation, known. We report here that phosphorylation of eukaryotic elongation factor-2 (eEF2), an indicator for translational elongation attenuation, is correlated with input that produces taste memory consolidation in the relevant cortex of rat. The temporal pattern of eEF2 phosphorylation is similar to extra-cellular regulated kinase 2 (ERK2) activation and S6K1 phosphorylation, which are known to stimulate translation initiation. In addition, increased eEF2 phosphorylation and increased alphaCaMKII expression is detected in a synaptoneurosomal fraction made from taste cortex following memory consolidation. These results suggest that increased initiation rate together with decreased elongation rate, during memory consolidation, shift the rate-limiting step of protein synthesis, to produce a local switch-like effect in the expression of neuronal proteins.
在多种物种中，不同学习范式后的记忆巩固已被证明依赖于蛋白质合成。然而，尚不清楚蛋白质合成的调节是否是巩固过程的关键组成部分，也不清楚任何受翻译调控的蛋白质的身份。我们在此报告，真核生物延伸因子2（eEF2）的磷酸化，作为翻译延伸衰减的指标，与在大鼠相关皮层中产生味觉记忆巩固的输入相关。eEF2磷酸化的时间模式类似于细胞外调节激酶2（ERK2）激活和S6K1磷酸化，已知它们会刺激翻译起始。此外，在记忆巩固后，从味觉皮层制备的突触神经小体组分中检测到eEF2磷酸化增加和αCaMKII表达增加。这些结果表明，在记忆巩固过程中，起始速率增加和延伸速率降低共同改变了蛋白质合成的限速步骤，从而在神经元蛋白质表达中产生局部开关样效应。
