Roth J A, Marcucci K, Lin W H, Napoli J L, Wagner J A, Rabin R
Department of Pharmacology, State University of New York, Buffalo 14214.
J Neurochem. 1991 Aug;57(2):708-13. doi: 10.1111/j.1471-4159.1991.tb03803.x.
Galactosyltransferase (GALTase) activity was measured in differentiating PC12 cells induced by either forskolin or 2-chloroadenosine. The specific activity of GALTase in whole cells and isolated Golgi membranes increased as early as 3 h after initiating treatment with 2-chloroadenosine, and maximal activity was reached at approximately 12 h. In two mutant PC12 cell lines deficient in protein kinase A, both forskolin and 2-chloroadenosine failed to increase GALTase activity. The adenosine A2 receptor antagonist, xanthine amine congener, prevented 2-chloroadenosine stimulation of GALTase, demonstrating that this adenosine derivative was mediating its effect via the A2 receptor. These data suggest that GALTase activity during PC12 cell differentiation is regulated by cyclic AMP (cAMP)- and protein kinase A-dependent processes. In support of the role of cAMP in regulating GALTase activity were studies with murine PC carcinoma cells demonstrating that the greatest stimulation of GALTase activity occurred with cells treated with both retinoic acid and dibutyryl cAMP.
在由福斯可林或2-氯腺苷诱导分化的PC12细胞中测定了半乳糖基转移酶（GALTase）活性。在用2-氯腺苷开始处理后3小时，全细胞和分离的高尔基体膜中GALTase的比活性就开始增加，在大约12小时达到最大活性。在两种缺乏蛋白激酶A的突变PC12细胞系中，福斯可林和2-氯腺苷均未能增加GALTase活性。腺苷A2受体拮抗剂黄嘌呤胺类似物可阻止2-氯腺苷对GALTase的刺激，表明这种腺苷衍生物是通过A2受体介导其作用的。这些数据表明，PC12细胞分化过程中的GALTase活性受环磷酸腺苷（cAMP）和蛋白激酶A依赖性过程的调节。用鼠PC癌细胞进行的研究支持了cAMP在调节GALTase活性中的作用，这些研究表明，视黄酸和二丁酰cAMP联合处理的细胞对GALTase活性的刺激最大。
