Functional studies of single-site variants in the calmodulin-binding domain of RC3/neurogranin in Xenopus oocytes.
Functional studies of single-site variants in the calmodulin-binding domain of RC3/neurogranin in Xenopus oocytes.
复制标题
非洲爪蟾卵母细胞 RC3/神经粒蛋白钙调蛋白结合域单位点变异的功能研究。
DOI：
10.1016/s0304-3940(96)13203-1
复制
发表时间：
1996
影响因子：
2.5
通讯作者：
Cohen,RW
中科院分区：
文献类型：
--
作者：
Watson,JB;Margulies,JE;Coulter2nd,PM;Gerendasy,DD;Sutcliffe,JG;Cohen,RW
在非洲爪蟾卵母细胞中异源表达 RC3/神经颗粒蛋白钙调蛋白结合域的单位点变异，以检查它们对血清素诱发电流的影响。 RC3变体丝氨酸36→丙氨酸（Ser36→Ala）、丝氨酸36→甘氨酸（ser36→Gly）和苯丙氨酸37→色氨酸（Phe37→Trp），它们与钙调蛋白结合，但缺乏蛋白激酶C（PKC）磷酸化，在卵母细胞中表现出与对照卵母细胞相似的血清素诱发的Ca2+依赖性Cl电流。丝氨酸36→天冬氨酸（Ser36→天冬氨酸）变体不结合钙调蛋白并模仿RC3的PKC磷酸化状态，以与野生型类似的方式显着增强血清素诱发的电流。结果表明，RC3 不仅调节树突棘中游离钙调蛋白的可用性，而且在磷酸化时，独立刺激 G 蛋白偶联的第二信使途径，产生肌醇 1,4,5-三磷酸 (IP3)、二酰基甘油 (DAG) 和细胞内 Ca2+。
Single-site variants in the calmodulin-binding domain of RC3/neurogranin were heterologously expressed in Xenopus oocytes to examine their effects on serotonin-evoked currents. RC3 variants serine36→ alanine (Ser36→ Ala), serine36→ glycine (ser36→ Gly), and phenylalanine37→ tryptophan (Phe37→ Trp), which bind calmodulin but are deficient in protein kinase C (PKC) phosphorylation, display serotonin-evoked Ca2+-dependent Cl−currents in oocytes similar to control oocytes. A serine36→ aspartate (Ser36→ Asp) variant, which does not bind calmodulin and mimics the PKC-phosphorylated state of RC3, significantly enhances serotonin-evoked currents in a manner similar to wild-type. The results suggest that RC3 not only regulates the availability of free calmodulin in a dendritic spine but also, when phosphorylated, independently stimulates G-protein coupled second messenger pathways that generate inositol 1,4,5-triphosphate (IP3), diacylglycerol (DAG) and intracellular Ca2+.