Calcium/calmodulin-dependent protein kinase II expression in motor neurons: Effect of axotomy
Calcium/calmodulin-dependent protein kinase II expression in motor neurons: Effect of axotomy
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DOI：
10.1002/(sici)1097-4695(19971120)33:6
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发表时间：
1997-11-20
期刊：
影响因子：
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通讯作者：
McQuarrie, IG
中科院分区：
文献类型：
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作者：
Lund, LM;McQuarrie, IG
虽然钙离子/钙调素依赖性（CaM）蛋白激酶II亚型是目前在神经系统中的高金额，在体内表达，定位和功能的许多方面仍然未被探索，在发展过程中，钙调素激酶II α和II β的差异表达，在这里，我们研究了钙调素激酶II亚型在SD大鼠坐骨运动神经元轴突切断术前后。切断L4-5脊神经，用荧光探针逆行标记神经元，抗CaM激酶II β抗体在运动神经元中呈免疫反应性，切断后4天降至低水平，用核糖核酸探针原位杂交发现类似反应，mRNA和蛋白表达的减少仅限于荧光运动神经元，对于CaM激酶II α，同胞杂交显示其mRNA在坐骨运动神经元中，密度不受轴突切断的影响，然而，这些神经元也增大，表明表达上调，北方印迹证实mRNA增加，我们在轴突切断前后的坐骨运动神经元胞体中未发现CaM激酶II α免疫反应性。这表明CaM激酶II α在轴突或树突中，或以其它方式不可用于抗体。使用具有挤压损伤的大鼠，我们放射性标记在细胞体中合成的轴突蛋白，并使用具有蛋白质印迹的二维聚丙烯酰胺凝胶电泳来鉴定CaM激酶II α作为慢轴突运输的组分，激酶同种型的这种差异调节和表达表明了单独和独特的细胞内作用。因为我们发现CaM激酶II β在轴突再生期间下调，其在这些神经元中的作用可能与突触传递有关，CaM激酶II α似乎支持轴突再生，（C）1997 John Wiley & Sons，Inc.
Although Ca2+/calmodulin-dependent (CaM) protein kinase II isoforms are present in the nervous system in high amounts, many aspects of in vivo expression, localization, and function remain unexplored, During development, CaM kinase II alpha and II beta are differentially expressed, Here, we examined CaM kinase II isoforms in Sprague-Dawley rat sciatic motor neurons before and after axotomy. We cut the L4-5 spinal nerves unilaterally and exposed the proximal nerve stumps to a fluoroprobe, to retrogradely label the neurons of origin, Anti-CaM kinase II beta antibody showed immunoreactivity in motor neurons, which decreased to low levels by 4 days after axotomy, We found a similar response by in situ hybridization with riboprobes, The decrease in expression of mRNA and protein was confined to fluorescent motor neurons, For CaM kinase II alpha, in sib hybridization showed that the mRNA was in sciatic motor neurons, with a density unaffected by axotomy, However, these neurons were also enlarged, suggesting an up-regulation of expression, Northern blots confirmed an mRNA increase, We were unable to find CaM kinase II alpha immunoreactivity before or after axotomy in sciatic motor neuron cell bodies, suggesting that CaM kinase II alpha is in the axons or dendrites, or otherwise unavailable to the antibody, Using rats with crush lesions, we radiolabeled axonal proteins being synthesized in the cell body and used two-dimensional polyacrylamide gel electrophoresis with Western blots to identify CaM kinase II alpha as a component of slow axonal transport, This differential regulation and expression of kinase isoforms suggests separate and unique intracellular roles, Because we find CaM kinase II beta down-regulates during axonal regrowth, its role in these neurons may be related to synaptic transmission, CaM kinase II alpha appears to support axonal regrowth, (C) 1997 John Wiley & Sons, Inc.