CALCIUM METABOLISM AND PROTEIN PHOSPHORYLATION IN NEURONAL SYSTEMS

研究一直在继续，以了解其调节和作用。 神经系统中神经丝的磷酸化。轴突 鱿鱼巨型轴突富含神经丝的制剂中含有第二 高分子磷酸化的信使非依赖性蛋白激酶 400和220 kDa鱿鱼神经丝蛋白亚基以及 外源底物。两种主要的激酶活性是。分开的和 以这种制剂为特点的。其中一种强烈的磷酸化 并被cAMP依赖的选择性抑制剂抑制 激活剂，维普泰德。第二个激酶活性有效地被磷酸化 α-酪蛋白，不受维肽和肝素的抑制。这个 α-酪蛋白磷酸化活性是主要活性。 负责神经丝蛋白的磷酸化，而不是 被不同的激酶抑制剂所抑制。一种新合成的异喹啉 特异性抑制纯化的酪蛋白激酶-I的衍生物(CKI-7) 是轴突神经细丝蛋白激酶的有效抑制剂。 物理、生化和药理研究表明， 与轴突神经细丝相关的主要激酶活性类似于 酪蛋白激酶1。哺乳动物神经细丝相关的激酶似乎 变得更复杂。对牛只有部分抑制作用 酪蛋白激酶I抑制剂和胰酶对神经丝蛋白激酶活性的影响 神经丝蛋白亚基(NF-M)表达后的肽图 牛神经丝蛋白激酶的磷酸化有一些相似之处 当被纯化的酪蛋白激酶I或酪蛋白激酶11磷酸化时。 CAMP依赖的激酶使不同的多肽在核因子-M上磷酸化。我们有 测定了鱿鱼神经元中间丝蛋白的序列， 全长约59 kDa，使用的是鱿鱼视叶的cDNA文库。 这种蛋白质是神经组织特有的，存在于轴浆中。 巨大的轴突。在结构上，它的杆状结构域具有共同的特征 对于哺乳动物的IV型(神经丝)和III型(波形蛋白，GFAP) 中间丝蛋白和层蛋白。通过突出显示 这两种动物之间保守的核因子蛋白序列， 在大约5.7亿年前发生了分化，这种mRNA的序列 将有助于阐明核因子-蛋白质中重要的功能结构域。

Studies have been continued to understand the regulation and role of neurofilament phosphorylation in the nervous system. Axonal neurofilament-rich preparation from squid giant axon contains second messenger-independent protein kinases that phosphorylate high molecular weight >400 and 220 kDa squid neurofilament protein subunits, as well as exogenous substrates. Two major kinase activities were. separated and characterized in this preparation. One of these strongly phosphorylated kemptide and was inhibited by the selective inhibitors of cAMP-dependent kinase, wiptide. The second kinase activity effectively phosphorylated alpha-casein and was not inhibited by wiptide and heparin. The alpha-casein phosphorylating activity was the principal activity responsible for neurofilament protein phosphorylation and was not inhibited by various kinase inhibitors. A newly synthesized isoquinoline derivative (CKI-7) that specifically inhibited purified casein kinase-I was the effective inhibitor of the axonal neurofilament protein kinase. The physical, biochemical and pharmacological studies indicated that the major kinase activity associated with axonal neurofilaments is like a casein kinase 1. The mammalian neurofilament associated kinases appear to be more complex. There was only a partial inhibition of bovine neurofilament kinase activity by casein kinase I inhibitor and the tryptic peptide maps of neurofilament protein subunit (NF-M) after its phosphorylation by bovine neurofilament kinase showed some similarities when phosphorylated by purified casein kinase I or casein kinase 11. The cAMP-dependent kinase phosphorylated distinct peptides on NF-M. We have determined the sequence of a squid neuronal intermediate filament protein, approximately 59 kDa, using a cDNA library made from squid optic lobe. This protein is specific to neural tissue, and is present in the axoplasm of the giant axon. Structurally, its rod domain possesses features common to mammalian Type IV (neurofilament) and Type III (vimentin, GFAP) intermediate filament proteins as well as Lamins. By highlighting those sequences of NF-proteins that are conserved between these two animals, which diverged around 570 million years ago, the sequence of this mRNA will help elucidate functionally important domains in NF-proteins.