Anand-Srivastava M B, Srivastava A K
Clinical Research Institute of Montreal, Quebec, Canada.
Mol Cell Biochem. 1990 Jan 18;92(1):91-8. doi: 10.1007/BF00220724.
The effects of purified Ca2+, phospholipid-dependent protein kinase (C-kinase) were studied on adenylate cyclase activity from rat brain striatum. C-kinase treatment of the membranes stimulated adenylate cyclase activity, the maximal stimulation between 50-80% was observed at 3.5 U/ml, whereas the catalytic subunit of cAMP dependent protein kinase did not show any effect on enzyme activity. The inclusion of Ca2+ and phosphatidyl serine did not augment the percent stimulation of adenylate cyclase by C-kinase, however EGTA inhibited the stimulatory effect of C-kinase on enzyme activity. Furthermore, the known inhibitors of C-kinase such as polymyxin-B and 1-(5-Isoquinoline sulfonyl)-2-methylpiperazine dihydrochloride (H-7) also inhibited the stimulatory effect of C-kinase on adenylate cyclase activity. In addition, in the presence of GTP the stimulatory effects of C-kinase on basal and N-Ethylcarboxamide adenosine- (NECA-), dopamine-(DA) and forskolin- (FSK) sensitive adenylate cyclase activities were augmented. On the other hand, the inhibitory effect of high concentrations of GTP on enzyme activity was attenuated by C-kinase treatment. In addition, oxotremorine inhibited adenylate cyclase activity in a concentration dependent manner, with an apparent Ki of about 10 microM and C-kinase treatment almost completely abolished this inhibition. These data suggest that C-kinase may play an important role in the regulation of adenylate cyclase activity possibly by interacting with a guanine nucleotide regulatory protein.
研究了纯化的钙离子、磷脂依赖性蛋白激酶（C激酶）对大鼠脑纹状体腺苷酸环化酶活性的影响。用C激酶处理膜可刺激腺苷酸环化酶活性，在3.5 U/ml时观察到最大刺激为50 - 80%，而环磷酸腺苷依赖性蛋白激酶的催化亚基对酶活性没有任何影响。加入钙离子和磷脂酰丝氨酸并没有增强C激酶对腺苷酸环化酶的刺激百分比，然而乙二醇双四乙酸（EGTA）抑制了C激酶对酶活性的刺激作用。此外，C激酶的已知抑制剂如多粘菌素B和1 -（5 -异喹啉磺酰基）- 2 -甲基哌嗪二盐酸盐（H - 7）也抑制了C激酶对腺苷酸环化酶活性的刺激作用。另外，在存在鸟苷三磷酸（GTP）的情况下，C激酶对基础的、对N -乙基羧酰胺腺苷（NECA）、多巴胺（DA）和福斯高林（FSK）敏感的腺苷酸环化酶活性的刺激作用增强。另一方面，高浓度GTP对酶活性的抑制作用通过C激酶处理而减弱。此外，氧化震颤素以浓度依赖性方式抑制腺苷酸环化酶活性，表观抑制常数（Ki）约为10微摩尔，C激酶处理几乎完全消除了这种抑制作用。这些数据表明，C激酶可能通过与鸟嘌呤核苷酸调节蛋白相互作用，在腺苷酸环化酶活性的调节中发挥重要作用。
