Laminin activates CaMK-II to stabilize nascent embryonic axons
Laminin activates CaMK-II to stabilize nascent embryonic axons
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DOI：
10.1016/j.brainres.2006.03.099
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发表时间：
2006-05-30
期刊：
影响因子：
2.9
通讯作者：
Tombes, Robert M.
中科院分区：
文献类型：
--
作者：
Easley, Charles A.;Faison, Milton O.;Tombes, Robert M.
在神经元中，层粘连蛋白与其受体β 1整联蛋白的相互作用伴随着胞质Ca 2+的增加。神经元的行为受到CaMK-II的影响，CaMK-II是一种II型Ca 2 +/钙调素依赖性蛋白激酶，富含于小鼠胚胎神经元的轴突中。在这项研究中，我们试图确定CaMK-II是否被层粘连蛋白激活，如果是这样，CaMK-II如何影响轴突的生长和稳定性。将P19胚状体接种在层粘连蛋白-1（EHS层粘连蛋白）上1天内，轴突生长至200 μ m。发现激活的CaMK-II沿着轴突富集，并且在生长锥中富集，如使用磷酸-Thr（287）特异性CaMK-II抗体检测的。发现β 1整联蛋白在沿着轴突和生长锥中以相似的模式存在。直接抑制1天大神经元中的CaMK-II立即冻结生长锥动力学，扰乱F-肌动蛋白，并最终导致轴突收缩。塌陷的轴突残余物表现出磷酸化CaMK-II水平降低。用β 1整联蛋白阻断抗体（CD 29）处理1天神经元也会减少轴突长度和磷酸化CaMK-II水平，并且与CaMK-II抑制剂一样，减少CaMK-II激活。在这些培养物中检测到的几种CaMK-II变体中，S2-kDa δ变体优先与肌动蛋白和β（3）微管蛋白相关，如通过相互免疫沉淀法测定的。我们的发现表明，层粘连蛋白对δ CaMK-II的持续激活通过其对肌动蛋白细胞骨架的影响稳定了新生胚胎轴突。(c)2006 Elsevier B. V.保留所有权利。
In neurons, the interaction of laminin with its receptor, beta 1 integrin, is accompanied by an increase in cytosolic Ca2+. Neuronal behavior is influenced by CaMK-II, the type II Ca2+/calmodulin-dependent protein kinase, which is enriched in axons of mouse embryonic neurons. In this study, we sought to determine whether CaMK-II is activated by laminin, and if so, how CaMK-II influences axonal growth and stability. Axons grew up to 200 mu m within 1 day of plating P19 embryoid bodies on laminin-1 (EHS laminin). Activated CaMK-II was found enriched along the axon and in the growth cone as detected using a phospho-Thr(287) specific CaMK-II antibody. beta 1 integrin was found in a similar pattern along the axon and in the growth cone. Direct inhibition of CaMK-II in 1-day-old neurons immediately froze growth cone dynamics, disorganized F-actin and ultimately led to axon retraction. Collapsed axonal remnants exhibited diminished phospho-CaMK-II levels. Treatment of 1-day neurons with a beta 1 integrin-blocking antibody (CD29) also reduced axon length and phospho-CaMK-II levels and, like CaMK-II inhibitors, decreased CaMK-II activation. Among several CaMK-II variants detected in these cultures, the S2-kDa delta variant preferentially associated with actin and beta(3) tubulin as determined by reciprocal immunoprecipitation. our findings indicate that persistent activation of delta CaMK-II by laminin stabilizes nascent embryonic axons through its influence on the actin cytoskeleton. (c) 2006 Elsevier B.V. All rights reserved.