Regulation of the superoxide-generating NADPH oxidase by a small GTP-binding protein and its stimulatory and inhibitory GDP/GTP exchange proteins.
Regulation of the superoxide-generating NADPH oxidase by a small GTP-binding protein and its stimulatory and inhibitory GDP/GTP exchange proteins.
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通过小的 GTP 结合蛋白及其刺激性和抑制性 GDP/GTP 交换蛋白来调节产生超氧化物的 NADPH 氧化酶。
DOI：
10.1016/s0021-9258(19)50005-9
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Y. Takai
中科院分区：
文献类型：
--
作者：
T. Mizuno;K. Kaibuchi;S. Ando;T. Musha;K. Hiraoka;K. Takaishi;M. Asada;H. Nunoi;I. Matsuda;Y. Takai
吞噬细胞中产生超氧阴离子的NADPH氧化酶系统至少由膜相关的细胞色素b558和三个胞浆组分组成，分别是SOCI/NCF-3/sigma 1/C1、Social/NCF-1/P47-Phox和SO-CIII/NCF-2/p67-Phox。分离得到了p47-Phox和p67-Phox，并确定了它们的一级结构，但SOI尚未得到很好的表征。在本研究中，我们首先从分化的HL-60细胞的胞浆部分提纯SOCI。纯化的SOI是一种小的GTP结合蛋白(G蛋白)，其M(R)约为22,000。这个小G蛋白的5‘-(3-O-硫代)三磷酸鸟苷结合型，而不是GDP结合型，显示了SOI活性。到目前为止测定的SOI的部分氨基酸序列与编码rac2p21的cDNA推导的氨基酸序列完全相同。纯化的小G蛋白，包括Ki-ras p21、SMG p21B/Rap1B p21、RhoA p21和rac1 p21均不具有SOI活性。这些结果表明，soi是一种小G蛋白，即使不完全相同，也与rac2 p21非常相似。刺激和抑制小G蛋白的GDP/GTP交换蛋白分别刺激和抑制SOI的GDP/GTP交换反应，分别称为SMG GDS和Rho GDI。SMG GDS和Rho GDI分别对NADPH氧化酶活性有促进作用和抑制作用。这些结果表明，SmG GDS和Rho GDI通过在吞噬细胞中通过rac2 p21或rac2相关的小G蛋白来调节产生超氧阴离子的NADPH氧化酶系统。
The superoxide-generating NADPH oxidase system in phagocytes consists of at least membrane-associated cytochrome b558 and three cytosolic components named SOCI/NCF-3/sigma 1/C1, SOCII/NCF-1/p47-phox, and SO-CIII/NCF-2/p67-phox. p47-phox and p67-phox were isolated, and their primary structures were determined, but SOCI has not been well characterized. In the present study, we first purified SOCI to homogeneity from the cytosol fraction of the differentiated HL-60 cells. The purified SOCI was a small GTP-binding protein (G protein) with a M(r) of about 22,000. The guanosine 5'-(3-O-thio)triphosphate-bound form, but not the GDP-bound form, of this small G protein showed the SOCI activity. The partial amino acid sequence of SOCI thus far determined was identical to the amino acid sequence deduced from the cDNA encoding rac2 p21. None of the purified small G proteins, including Ki-ras p21, smg p21B/rap1B p21, rhoA p21, and rac1 p21, showed the SOCI activity. These results indicate that SOCI is a small G protein very similar, if not identical, to rac2 p21. The GDP/GTP exchange reaction of SOCI was stimulated and inhibited by stimulatory and inhibitory GDP/GTP exchange proteins for small G proteins, named smg GDS and rho GDI, respectively. The NADPH oxidase activity was also stimulated and inhibited by smg GDS and rho GDI, respectively. These results indicate that the superoxide-generating NADPH oxidase system is regulated by both smg GDS and rho GDI through rac2 p21 or the rac2-related small G protein in phagocytes.