A blue-light-activated GTP-binding protein in the plasma membranes of etiolated peas.
A blue-light-activated GTP-binding protein in the plasma membranes of etiolated peas.
复制标题
黄化豌豆质膜中的蓝光激活 GTP 结合蛋白。
DOI：
10.1073/pnas.88.20.8925
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发表时间：
1991
影响因子：
11.1
通讯作者：
Kaufman,LS
中科院分区：
文献类型：
--
作者：
Warpeha,KM;Hamm,HE;Rasenick,MM;Kaufman,LS
异源三聚体GTP结合调节蛋白（G蛋白）已被鉴定为多种生物体中信号转导系统的一部分。在本文中，我们建立了与黄化豌豆顶芽质膜相关的G蛋白的存在。通过向质膜富集组分施用低通量的蓝光诱导GT3活性。该活性对红光照射没有反应，并且对GTP具有特异性。体外激发GT3活性的阈值小于10（-1）μ mol.m-2蓝光，与在相同组织中鉴定的蓝色低通量系统的参与一致。40-kDa多肽被针对G蛋白转导素α亚基的多克隆抗血清识别。该多肽还充当霍乱和百日咳毒素的ADP-核糖基化的底物。40-kDa多肽作为毒素介导的核糖基化的底物的能力是由蓝光照射介导的，这意味着40-kDa多肽是蓝光刺激的G蛋白的α亚基。40-kDa多肽仅在蓝光照射后结合GTP的不可水解的光亲和标记类似物。我们所描述的蛋白质可能作为G蛋白的α亚基在高等植物光介导的发育过程中起作用。
Heterotrimeric GTP-binding regulatory proteins (G proteins) have been identified as part of signal transduction systems in a wide variety of organisms. In this paper, we establish the presence of a G protein associated with the plasma membranes of the apical bud of etiolated peas. The GTPase activity is induced by low fluences of blue light administered to plasma membrane-enriched fractions. The activity is not responsive to red-light irradiation and is specific for GTP. The threshold for the excitation of the GTPase activity in vitro is less than 10(-1) mumol.m-2 of blue light, consistent with participation in the blue low-fluence system identified in the same tissue. A 40-kDa polypeptide is recognized by polyclonal antisera directed against the alpha subunit of the G protein transducin. The polypeptide also serves as a substrate for ADP-ribosylation by cholera and pertussis toxins. The ability of the 40-kDa polypeptide to serve as substrate for the toxin-mediated ribosylation is mediated by blue-light irradiation, implying that the 40-kDa polypeptide is the alpha subunit of a blue-light-stimulated G protein. The 40-kDa polypeptide binds a nonhydrolyzable photoaffinity-labeling analog of GTP only after irradiation with blue light. The protein we have described may function as an alpha subunit of a G protein active in the process of light-mediated development in higher plants.