A new factor for cellular signal transduction-Studies of the structures and functions of soluble GTP binding proteins

细胞信号转导的新因子——可溶性GTP结合蛋白的结构与功能研究

• 批准号: 03671171
• 负责人: YAJIMA Yukiko
• 金额: $ 1.34万
• 依托单位: The Tokyo Metropolitan Institute of Medical Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03671171/
• 关键词: GTP binding proteins (G proteins); alpha subunits; somatostatin; VIP; GH4CI cells; membranes; beta gamma subunits; 受容体刺激; G蛋白; Gi_2; βγサブユニット; 百日咳毒素; ADPーリボシル化; ミリスチン酸

Incubation of the GH_4C_1 rat pituitary cells with somatostatin (SRIF) decreased the level of alpha subunit of G_<i2> to 52% of control values in the crude membrane during the first 8 min, whereas the 274,000 x g supernatant (cytosolic fraction) showed clearly the alpha subunit of G_<i2> by immunoblotting. The resolved cytosolic fraction was ADP-ribosylated by pertussis toxin (PT) with betagamma complex. The effects of SRIF were inhibited by the pretreatment of GH_4C_1 cells with PT. Furthermore, the addition of vasoactive intestinal peptide (VIP) to intact GH_4C_1 cells also decreased the level of alpha subunit (50 KDa) of G_s in crude membranes, whereas the cytosolic fraction revealed the alpha subunit of G_s the during first 30 min. These data indicate that PT-sensitive or cholera toxin-sensitive G proteins in intact GH_4C_1 cells do indeed dissociate into alpha subunit and betagamma complex upon SRIF or VIP activation and release alpha subunits from the membrane to cytosol.

GH_4C_1大鼠垂体细胞与生长抑素(SRIF)孵育8分钟后，粗膜G&lt；i2&gt；α亚基水平下降至对照的52%，而274,000×g上清液(胞浆部分)免疫印迹显示G&lt；i2&gt；α亚基。以百日咳毒素(PT)与β-淀粉复合体为底物，将溶解的胞浆部分进行ADP核糖化。PT可抑制SRIF对GH_4C_1细胞的作用。此外，在完整的GH_4C_1细胞中加入血管活性肠肽后，GH_4C_1细胞粗膜中G_S的α亚基(50 KDa)水平也明显降低，而胞浆中的G_Sα亚基的含量在前30分钟就明显下降。这些数据表明，在完整的GH_4C_1细胞中，PT敏感或霍乱毒素敏感的G蛋白确实在SRIF或VIP激活时解离为α亚基和β-淀粉复合体，并从膜向胞浆释放α亚基。

项目成果

矢島 由紀子: "血小板活性化の生化学(第2章内分泌細胞とGTP結合蛋白質)" 金芳堂, 13 (1991)

Yukiko Yajima：“血小板活化的生物化学（第 2 章内分泌细胞和 GTP 结合蛋白）”Kinhodo，13 (1991)

Y.YAJIMA,Y.Akita,T.Katada and T.Saito: "Somatostatin induces release of the α subunits of pertussis toxin-sensitive G proteins in native membranes and in intact GH_4C_1 rat pituitary cells" Mol.Cell.Endocrinol.

Y.YAJIMA、Y.Akita、T.Katada 和 T.Saito：“生长抑素诱导天然膜和完整 GH_4C_1 大鼠垂体细胞中百日咳毒素敏感 G 蛋白 α 亚基的释放”Mol.Cell.Endocrinol。