Purification and G Protein Subunit Regulation of a Phospholipase C-β from Xenopus laevis Oocytes*
Purification and G Protein Subunit Regulation of a Phospholipase C-β from Xenopus laevis Oocytes*
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非洲爪蟾卵母细胞磷脂酶 C-β 的纯化和 G 蛋白亚基调节*
DOI：
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发表时间：
1996
影响因子：
4.8
通讯作者：
Kendall Harden
中科院分区：
文献类型：
--
作者：
T. Filtz;Andrew D. Paterson;Kendall Harden
非洲爪哇卵母细胞既对百日咳毒素敏感，又对G蛋白偶联受体激活的肌醇脂信号不敏感。G蛋白亚基GαI、Gαo、GαQ、GαS和Gβγ都被认为是卵母细胞中磷脂酶C的激活剂。Ma等人。(Ma，H.W.，Blitzer，R.D.，Healy，E.C.，Premont，R.T.，Landau，E.M.和Iyengar，R.J.Biol.化学。268,19915-19918)克隆了非洲爪哇磷脂酶C(PLC-βX)，该基因与同工酶PLC-β同源。尽管该酶被认为是百日咳毒素敏感的卵母细胞肌醇脂信号通路中的一种信号蛋白，但G蛋白亚基对其调节作用尚未得到直接评估。因此，我们利用杆状病毒促进的PLC-βX在昆虫细胞中的高表达，并纯化了一个重组的150kDa同工酶。PLC-βX催化磷脂酰肌醇(4，5)二磷酸和磷脂酰肌醇(4)一磷酸的水解，反应速度依赖于钙离子。重组PLC-βX可被GαQ和Gβγ激活。与其他同工酶相比，PLC-βX对GαQ的敏感性低于PLC-β1，但与PLC-β2和PLC-βT相似。PLC-βX对Gβγ刺激的敏感性高于PLC-β1，但低于PLC-β2和βT。或Gαo。这些结果与PLC-βX受Gq家族α亚基和Gβγ调控的观点一致，不支持百日咳毒素敏感G蛋白的α亚基直接参与该蛋白调控的观点。
Xenopus oocytes exhibit both pertussis toxin-sensitive and -insensitive inositol lipid signaling responses to G protein-coupled receptor activation. The G protein subunits Gαi, Gαo, Gαq, Gαs, and Gβγ all have been proposed to function as activators of phospholipase C in oocytes. Ma et al. (Ma, H.-W., Blitzer, R. D., Healy, E. C., Premont, R. T., Landau, E. M., and Iyengar, R. J. Biol. Chem. 268, 19915-19918) cloned a Xenopus phospholipase C (PLC-βX) that exhibits homology to the PLC-β class of isoenzymes. Although this enzyme was proposed to function as a signaling protein in the pertussis toxin-sensitive inositol lipid signaling pathway of oocytes, its regulation by G protein subunits has not been directly assessed. As such we have utilized baculovirus-promoted overexpression of PLC-βX in Sf9 insect cells and have purified a recombinant 150-kDa isoenzyme. PLC-βX catalyzes hydrolysis of phosphatidylinositol(4,5)bisphosphate and phosphatidylinositol(4)monophosphate, and reaction velocity is dependent on Ca2+. Recombinant PLC-βX was activated by both Gαq and Gβγ. PLC-βX exhibited a higher apparent affinity for Gαq than Gβγ, and Gαq was more efficacious than Gβγ at lower concentrations of PLC-βX. Relative to other PLC-β isoenzymes, PLC-βX was less sensitive to stimulation by Gαq than PLC-β1 but similar to PLC-β2 and PLC-βT. PLC-βX was more sensitive to stimulation by Gβγ than PLC-β1 but less sensitive than PLC-β2 and PLC-βT. In contrast PLC-βX was not activated by the pertussis toxin substrate G proteins Gαi1, Gαi2, Gαi3, or Gαo. These results are consistent with the idea that PLC-βX is regulated by α-subunits of the Gq family and by Gβγ and do not support the idea that α-subunits of pertussis toxin-sensitive G proteins are directly involved in regulation of this protein.
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非洲爪蟾卵母细胞中受体诱发的 Cl- 电流是通过 β 型磷脂酶 C 介导的。该酶新形式的克隆。
DOI：
--
发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Ma,HW;Blitzer,RD;Healy,EC;Premont,RT;Landau,EM;Iyengar,R
通讯作者：
Iyengar,R
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DOI：
--
发表时间：
1991
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Padrell,E;Carty,DJ;Moriarty,TM;Hildebrandt,JD;Landau,EM;Iyengar,R
通讯作者：
Iyengar,R
禽类红细胞 G α 11 和 β γ 亚基刺激的磷脂酶 C-β 的分子克隆、表达和调节活性。
DOI：
10.1042/bj3160559
发表时间：
1996
期刊：
The Biochemical journal
影响因子：
--
作者：
Waldo,GL;Paterson,A;Boyer,JL;Nicholas,RA;Harden,TK
通讯作者：
Harden,TK
非洲爪蟾卵母细胞中表达的 α1B-肾上腺素能受体与磷脂酶 C 途径的偶联。
DOI：
--
发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Blitzer,RD;Omri,G;DeVivo,M;Carty,DJ;Premont,RT;Codina,J;Birnbaumer,L;Cotecchia,S;Caron,MG;Lefkowitz,RJ
通讯作者：
Lefkowitz,RJ
G 蛋白调节的磷脂酶 C 的 β γ 亚基激活。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Boyer,JL;Waldo,GL;Harden,TK
通讯作者：
Harden,TK