CATALYTIC SUBUNIT OF MOLLUSCAN CYCLIC AMP-DEPENDENT PROTEIN KINASES

这项奋进的目的是通过cDNA分离和表征， 克隆，环腺苷酸依赖性蛋白激酶（A 激酶）存在于海洋软体动物的神经系统中 并确定这些蛋白质如何参与神经元 调变 目前的工作重点是隔离和 A激酶的四个相关催化（C）亚基的表征， 通过选择性剪接从单个基因转录的mRNA产生， 与哺乳动物同种型的比较， 独立基因 存在于所述多肽中的独特氨基酸序列 交替表达的轴突使得产生轴突特异性 用于区分核酸和蛋白质的同种型的探针 程度. 已经产生了抗体来区分 具有交替的N-末端的蛋白质。 利用这些工具，我们打算 研究C亚单位如何对神经调节剂作出反应， A激酶级联。 除了这些异构体，第五，更多 克隆了一个远缘同种型，发现它是 在精子中表达。 该激酶具有大约58%的氨基酸 与其他C亚基同源，并通过EM定位 免疫细胞化学观察到成熟精子轴丝基部有明显突起。 目前正在努力确定这种激酶是否有助于 获得精子活力或参与受精。

The aim of this endeavor was to isolate and characterize, through cDNA cloning, the various subunits of cyclic AMP-dependent protein kinase (A kinase) present in the nervous system of the marine mollusc Aplysia californica and to determine how these proteins participate in neuronal modulation. The current work focuses on the isolation and characterization of four related catalytic (C) subunits of A kinase that arise via alternative splicing of mRNA transcribed from a single gene by comparison to the mammalian isoforms which are transcribed from independent genes. Unique amino acid sequences present in the alternatively expressed axons make it possible to produce axon-specific probes to discriminate between isoforms at the nucleic acid and protein levels. Antibodies have already been generated that distinguish between proteins having alternate N-termini. Using these tools, we intend to investigate how C subunits respond to neuromodulators that act through the A kinase cascade. In addition to these isoforms, a fifth, more distantly related isoform was cloned and found to be exclusively expressed in sperm. This kinase has approximately 58% amino acid homology with the other C subunits, and localizes by EM immunocytochemistry to the base of the axoneme in mature spermatozoa. Efforts are currently underway to determine if this kinase contributes to the acquisition of sperm motility or participates in fertilization.