Jicha G A, Weaver C, Lane E, Vianna C, Kress Y, Rockwood J, Davies P
Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
J Neurosci. 1999 Sep 1;19(17):7486-94. doi: 10.1523/JNEUROSCI.19-17-07486.1999.
To elucidate the role cAMP-dependent protein kinase (PKA) phosphorylations on tau play in Alzheimer's disease, we have generated highly specific monoclonal antibodies, CP-3 and PG-5, which recognize the PKA-dependent phosphorylations of ser214 and ser409 in tau respectively. The present study demonstrates by immunohistochemical analysis, CP-3 and PG-5 immunoreactivity with neurofibrillary pathology in both early and advanced Alzheimer's disease, but not in normal brain tissue and demonstrates that cAMP-dependent protein kinase phosphorylations on tau precede or are coincident with the initial appearance of filamentous aggregates of tau. Studies using heat-stable preparations demonstrate that neither site appears to be phosphorylated to any appreciable extent in normal rodent or human brain. Further analysis demonstrates that the beta catalytic subunit of PKA (Cbeta), the beta II regulatory subunit of PKA (RIIbeta), and the 79 kDa A-kinase-anchoring-protein (AKAP79), are tightly associated with the neurofibrillary pathology, positioning cAMP-dependent protein kinase to participate directly in the pathological hyperphosphorylation of tau seen in Alzheimer's disease.
为了阐明环磷酸腺苷（cAMP）依赖性蛋白激酶（PKA）对tau蛋白的磷酸化作用在阿尔茨海默病中所起的作用，我们制备了高度特异性的单克隆抗体CP - 3和PG - 5，它们分别识别tau蛋白中丝氨酸214和丝氨酸409位点的PKA依赖性磷酸化。本研究通过免疫组织化学分析表明，CP - 3和PG - 5在早期和晚期阿尔茨海默病中均与神经原纤维病理改变呈免疫反应性，而在正常脑组织中则无此反应，这表明tau蛋白上cAMP依赖性蛋白激酶的磷酸化先于或与tau蛋白丝状聚集体的最初出现同时发生。使用热稳定制剂的研究表明，在正常啮齿动物或人类大脑中，这两个位点似乎均未发生明显的磷酸化。进一步分析表明，PKA的β催化亚基（Cβ）、PKA的βII调节亚基（RIIβ）以及79 kDa的A激酶锚定蛋白（AKAP79）与神经原纤维病理改变紧密相关，表明cAMP依赖性蛋白激酶直接参与了阿尔茨海默病中tau蛋白的病理性过度磷酸化过程。
