Saitoh T, Schwartz J H
Proc Natl Acad Sci U S A. 1983 Nov;80(21):6708-12. doi: 10.1073/pnas.80.21.6708.
We purified and radioiodinated calmodulin from Aplysia nervous tissue. Using blot analysis, we detected 14 calmodulin-binding proteins in extracts of the abdominal ganglion after gel electrophoresis in NaDodSO4. All 14 components are present in extracts from each of the major central Aplysia ganglia, but their relative proportions differed characteristically from one ganglion to another. When neural components are extracted with nonionic detergents in 2 M glycerol, we obtain a cytoplasmic and a membrane-cytoskeleton fraction. Of the 14 calmodulin-binding proteins, 2 are cytoplasmic, 10 are loosely associated, and 2 remain bound to the membrane-cytoskeleton complex. Treatment of isolated ganglia with serotonin, which has been shown to increase the content of cAMP within neurons, or with dibutyryl cAMP causes the partial dissociation of one of the loosely associated proteins, which has an apparent Mr of 55,000. In extracts prepared in the presence of glycerol and cAMP, this component also is dissociated from the membrane-cytoskeleton complex, but only if ATP is also present. These results suggest that a cAMP-dependent protein phosphorylation controls the subcellular distribution of the Mr 55,000 calmodulin-binding protein, whose state of phosphorylation itself, however, does not appear to be increased by cAMP.
我们从海兔神经组织中纯化并对钙调蛋白进行了放射性碘化。通过印迹分析，我们在十二烷基硫酸钠凝胶电泳后检测到腹神经节提取物中有14种钙调蛋白结合蛋白。所有这14种成分都存在于海兔主要中枢神经节的每一种提取物中，但它们的相对比例在不同神经节之间有显著差异。当用2M甘油中的非离子去污剂提取神经成分时，我们得到一个细胞质部分和一个膜 - 细胞骨架部分。在这14种钙调蛋白结合蛋白中，2种是细胞质的，10种是松散结合的，2种仍与膜 - 细胞骨架复合体结合。用已被证明能增加神经元内cAMP含量的5 - 羟色胺或二丁酰cAMP处理分离的神经节，会导致其中一种表观分子量为55,000的松散结合蛋白部分解离。在甘油和cAMP存在下制备的提取物中，只有当ATP也存在时，该成分才会从膜 - 细胞骨架复合体中解离。这些结果表明，一种cAMP依赖性蛋白磷酸化作用控制着分子量为55,000的钙调蛋白结合蛋白的亚细胞分布，然而，其磷酸化状态本身似乎并没有因cAMP而增加。
