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Localization and functional difference of various betagamma subunits of G protein

G蛋白各βγ亚基的定位及功能差异

基本信息

批准号：
06680639
负责人：
ASANO Tomiko
金额：
$ 1.41万
依托单位：
Institute for Developmental Research, Aichi Human Service Center
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680639/
关键词：
G Protein gamma subunit Primary structure Protein kinase C Phosphorylation Tissue distribution プロテインキナーゼC γサブユニツト

项目摘要

We have determined the primary structure of a novel gamma subunit (gamma12, previously designated gammaS1) of G protein purified from bovine spleen. The mature gamma12 protein composed of 68 amino acids had acetylated serine at the N-terminus and geranylgeranylated/carboxylmethylated cysteine at the Cterminus. This was consistent with the C-terminal prenylation signal in the amino acid sequence which was predicted from gamma12 cDNA isolated from a bovine spleen cDNA library. Among various gamma subunits (gamma1, gamma2, gamma3, gamma7 and gamma12), gamma12 has a unique property to be phosphorylated by protein kinase C.The phosphorylated amino acid residue was Ser1 (or Ser2). Exposure of Swiss 3T3 and aortic smooth muscle cells to phorbol 12-myristate 13-acetate ane NaF induced phosphorylation of gamma12.Stimulation of aortic smooth muscle cells with natural vasoactive agents such as angiotensin II and vasopressin also induced phosphorylation of gamma12. The extent of phosphorylation of betagamma12 in vitro was suppressed by a complex formation with Goalpha, which was relieved by the addition of GTPgammaS or aluminum fluoride. These results strongly suggest that gamma12 is phosphorylated by protein kinase C during activation of receptor (s) and G protein (s) in living cells. Then the localization of various forms of the gamma subunit of G protein was investigated by the use of antibodies against the respective gamma subunits. The gamma3 was expressed in neuronal cells, and gamma12 was the major gamma subunit in most nonneural cells. gamma2, gamma5 and gamma12 were distributed in a variety of tissues, but gamma2 was dominant in the brain.

我们已经确定了一个新的γ亚基（gamma 12，以前指定gammaS 1）的G蛋白纯化牛脾的一级结构。成熟的γ 12蛋白由68个氨基酸组成，N-末端为乙酰化丝氨酸，C-末端为香叶基香叶基/羧甲基化半胱氨酸。这与从牛脾cDNA文库分离的γ 12 cDNA预测的氨基酸序列中的C-末端异戊烯化信号一致。在各种γ亚基（γ 1、γ 2、γ 3、γ 7和γ 12）中，γ 12具有被蛋白激酶C磷酸化的独特性质。磷酸化的氨基酸残基是Ser 1（或Ser 2）。Swiss 3 T3和主动脉平滑肌细胞暴露于佛波醇12-肉豆蔻酸酯13-乙酸酯和NaF诱导γ 12磷酸化。用天然血管活性剂如血管紧张素II和加压素刺激主动脉平滑肌细胞也诱导γ 12磷酸化。β-γ 12在体外的磷酸化程度受到抑制的复合物形成与Goalpha，这是缓解了加入GTP γ S或氟化铝。这些结果有力地表明，在活细胞中，γ 12在受体和G蛋白的活化过程中被蛋白激酶C磷酸化。然后，通过使用针对相应的γ亚基的抗体，研究了G蛋白的γ亚基的各种形式的定位。γ 3在神经元细胞中表达，而γ 12是大多数非神经细胞中的主要γ亚基。γ 2、γ 5和γ 12分布于多种组织中，但γ 2在脑中占优势。