Guanine nucleotide regulation of [3H]vasopressin binding to liver plasma membranes and solubilized receptors. Evidence for the involvement of a guanine nucleotide regulatory protein.
Guanine nucleotide regulation of [3H]vasopressin binding to liver plasma membranes and solubilized receptors. Evidence for the involvement of a guanine nucleotide regulatory protein.
复制标题
鸟嘌呤核苷酸调节[3H]加压素与肝质膜和溶解受体的结合。
DOI：
10.1042/bj2400361
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Fain,JN
中科院分区：
文献类型：
--
作者：
Bojanic,D;Fain,JN
鸟嘌呤核苷酸调节蛋白可能参与加压素受体介导的大鼠肝脏多磷酸肌醇的分解。因此，我们研究了不可水解的鸟嘌呤核苷酸鸟苷5′-[β-γ-亚氨基]三磷酸（p[NH]ppG）对[3 H]加压素（[3 H]AVP）与肝质膜和去污剂提取物结合的影响。[3 H]AVP与膜中的一组高亲和力结合位点结合。添加p[NH]ppG降低受体结合的亲和力，而不改变最大结合容量。[~ 3 H]AVP与膜结合受体的解离速率也被p[NH]ppG增强。用十二烷基β-D-麦芽糖苷溶解[3 H] AVP-预标记的膜导致在溶液中不稳定的[3 H] AVP-受体复合物。将这些提取物在30 ℃下孵育5分钟导致结合的[3 H]AVP损失40%，而在p[NH]ppG存在下，损失54%。然而，当膜预标记与[3 H]AVP和p[NH]ppG，然后溶解，所得到的受体复合物仍然是温度不稳定的，但不敏感的进一步加入p[NH]ppG。可溶性血管加压素受体的分子大小通过凝胶过滤来估计。[3 H] AVP-受体复合物洗脱为单峰，表观分子大小为258 kDa。然而，没有检测到峰时，溶解的提取物从膜预标记的[3 H]AVP和p[NH]ppG，这表明该受体复合物在色谱分离。因此，高Mr复合物可能含有激素、其受体和鸟嘌呤核苷酸结合蛋白。
A guanine nucleotide regulatory protein may be involved in vasopressin-receptor-mediated polyphosphoinositide breakdown in rat liver. Therefore we examined the effects of the non-hydrolysable guanine nucleotide guanosine 5′-[beta gamma-imido]triphosphate (p[NH]ppG) on [3H]vasopressin ([3H]AVP) binding to hepatic plasma membranes and detergent extracts. [3H]AVP bound to a single set of high-affinity binding sites in membranes. Addition of p[NH]ppG decreased the affinity of receptor binding without altering the maximal binding capacity. The rate of dissociation of [3H]AVP from membrane-bound receptors was also enhanced by p[NH]ppG. Solubilization of [3H]AVP-prelabelled membranes with dodecyl beta-D-maltoside resulted in a [3H]AVP-receptor complex that was unstable in solution. Incubation of these extracts for 5 min at 30 degrees C resulted in a 40% loss of bound [3H]AVP, whereas in the presence of p[NH]ppG there was a 54% loss. However, when membranes were prelabelled with [3H]AVP and p[NH]ppG and then solubilized, the resulting hormone-receptor complex was still temperature-labile but insensitive to the further addition of p[NH]ppG. The molecular size of soluble vasopressin receptors was estimated by gel filtration. The [3H]AVP-receptor complex was eluted as a single peak with an apparent molecular size of 258 kDa. However, no peak was detected when solubilized extract was made from membranes prelabelled with [3H]AVP and p[NH]ppG, suggesting that this receptor complex had dissociated during chromatography. It is possible therefore that the high-Mr complex contains the hormone, its receptor and a guanine nucleotide binding protein.