A nucleotide regulatory site for somatostatin inhibition of adenylate cyclase in S49 lymphoma cells
A nucleotide regulatory site for somatostatin inhibition of adenylate cyclase in S49 lymphoma cells
复制标题
S49淋巴瘤细胞中生长抑素抑制腺苷酸环化酶的核苷酸调节位点
作者：
K. Jakobs;K. Aktories;G. Schultz
S49淋巴瘤细胞的cyc−变体已成为研究腺苷酸环化酶刺激的组分和机制的有力工具，因为这些细胞缺乏鸟嘌呤核苷酸调节位点（Ns）介导的激素、鸟嘌呤核苷酸、霍乱毒素和氟化物诱导的酶刺激1。由于这种缺陷，这些细胞的膜已被用于通过插入来自其他细胞类型的偶联组分来重建系统2 -4。对鸟苷酸敏感的腺苷酸环化酶不仅受到激素的刺激，而且还可以受到多种激素和神经递质的抑制5 -8，并且有证据表明激素抑制可能由不同的鸟嘌呤核苷酸调节位点介导5 -8。因此，对缺乏功能性Ns的cyc-细胞的研究可能会回答这个尚未解决的重要问题。我们最近证实，稳定的GTP类似物可以抑制由纯化的预活化的Ns或毛喉素刺激的环腺苷酸环化酶，即使在没有功能性Ns的情况下，毛喉素也可以激活腺苷酸环化酶（参考文献10）。这些数据表明，这些NS-缺陷细胞含有抑制性鸟嘌呤核苷酸位点，Ni。为了加强这一概念，我们研究了环腺苷酸环化酶是否可以被激素抑制。我们在这里报告，生长抑素降低cyclc −细胞中的环AMP水平，抑制毛喉素刺激的腺苷酸环化酶，并导致cyclc −膜中高亲和力GTdR活性的伴随增加。这些数据强烈表明，激素和鸟嘌呤核苷酸诱导的腺苷酸环化酶抑制在cyc−细胞是由镍介导的，镍的激活和失活的机制是类似的那些建立的Ns。
The cyc− variants of S49 lymphoma cells have served as powerful tools for studying the components and mechanisms of hormone-induced adenylate cyclase stimulation, as these cells are deficient in the guanine nucleotide regulatory site (Ns) mediating hormone, guanine nucleotide, cholera toxin and fluoride-induced stimulations of the enzyme1. Because of this deficiency, membranes of these cells have been used for reconstitution of the system by inserting the coupling component derived from other cell types2–4. The hormone-sensitive adenylate cyclase is not only stimulated by hormones but can also be inhibited by a wide variety of hormones and neurotransmitters5–8, and there is some evidence that hormonal inhibition may be mediated by a distinct guanine nucleotide regulatory site5–8. Studies in cyc− cells lacking a functional Ns may therefore answer this unresolved, important question. We have recently observed9 that stable GTP analogues can inhibit cyc− adenylate cyclase stimulated by purified, preactivated Ns or forskolin, which can activate adenylate cyclase even in the absence of a functional Ns (ref. 10). The data indicated that these Ns-deficient cells contain an inhibitory guanine nucleotide site, Ni. To strengthen this concept, we investigated whether the cyc− adenylate cyclase can be inhibited by a hormone. We report here that somatostatin decreases cyclic AMP levels in cyc− cells, inhibits the forskolin-stimulated adenylate cyclase and causes a concomitant increase in a high affinity GTPase activity in cyc− membranes. The data strongly suggest that both the hormone- and guanine nucleotide-induced adenylate cyclase inhibitions in cyc− cells are mediated by Ni and that the mechanisms of activation and inactivation of Ni are similar to those established for Ns.
腺苷酸环化酶的调节成分。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Hanski,E;Sternweis,PC;Northup,JK;Dromerick,AW;Gilman,AG
通讯作者：
Gilman,AG
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Sternweis,PC;Northup,JK;Smigel,MD;Gilman,AG
通讯作者：
Gilman,AG