The Development of the Strategy for the Presumption of the Tertiary Structure of Protein Kinases by Specific Inhibitors

蛋白激酶是将Pi转化为某些蛋白质的酶。这些反应已被揭示参与许多细胞功能的调节。目前蛋白激酶的种类已超过100种，有必要从结构和功能的角度对蛋白激酶进行研究，以阐明每种蛋白激酶的生理功能。本研究的目的是：（1）推测蛋白激酶功能域的三级结构;（2）开发新的特异性蛋白激酶抑制剂;（3）阐明蛋白激酶的生理功能。钙/钙调素依赖性蛋白激酶II特异性抑制剂的应用H-89是cAMP依赖性蛋白激酶Ⅱ（CaM kinase Ⅱ）的特异性抑制剂，（A-激酶），揭示了A-激酶参与了c-fos基因转录的调节，并参与了早期基因诱导的调节。我们成功地合成了一种新型的特异性抑制剂，用于CaM激酶II或MAP激酶激活的新型蛋白激酶，MAP激酶是调节各种细胞外刺激诱导的信号的关键分子。KN-62对钙调素依赖性蛋白激酶CaM激酶V有抑制作用。在此基础上，我们认为CaM激酶II的钙调素结合结构域与CaM激酶V的钙调素结合结构域非常相似。这两种蛋白激酶的结合结构域在阐明蛋白激酶的功能、开发新的特异性抑制剂以及明确CaM激酶II和CaM激酶V的钙调素结合结构域的三级结构之间的相似性方面取得了成功。

Protein kinases are enzymes which tansfer Pi into some proteins. These reactions have been revealed to be involved in the regulation of many cellular function. now that the number of protein kinases has reached to over 100, it is essential to study them with structural and functional approach to clarify the physiological function of each protein kinase. The aim of our study is, (1) to presume the tertiary structure of the functional domain of protein kinase, (2) to develop the new specific protein kinase inhibitors, and (3), it is final aim, to clarify the physiological function of protein kinases. Using specific inhibitor for Ca2+/calmodulin dependent protein kinase II(CaM kinase II), KN-62, we succeeded in revealing the involvement of CaM kinase II in smooth muscle contraction, the central regulation of systemic pressure, secretion of insulin or endotherin and so on. H-89, specific inhibitor for cAMP dependent protein kinase(A-kinase), revealed the involvement of the A-kinase in the regulation of transcription of c-fos gene, and in the regulation of induction of immediately early genes. We succeeded in synthesizing the novel specific inhibitor for CaM kinase II or for the novel protein kinase activated by MAP kinase, which is a key molecule for regulating the signals induced by various extracellular stimuli. KN-62 was revealed to inhibit CaM kinase V which was a novel Ca2+/calmodulin dependent protein kinase with respect with calmodulin. On the basis of this result, it will be suggested that the calmodulin binding domain of CaM kinase II is quite similar to that of CaM kinase V.Taken together, we succeeded in clarifying the function of protein kinases, in developing the new specific inhibitors, and in clearing the similarity between the tertiary structure of calmodulin binding domain of CaM kinase II and CaM kinase V.