Requirement of ADP-ribosylation for the pertussis toxin-induced alteration in electrophoretic mobility of G-proteins.
Requirement of ADP-ribosylation for the pertussis toxin-induced alteration in electrophoretic mobility of G-proteins.
复制标题
百日咳毒素诱导的 G 蛋白电泳迁移率改变需要 ADP-核糖基化。
DOI：
10.1016/s0006-291x(05)81327-0
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发表时间：
1991
影响因子：
3.1
通讯作者：
Law,PY
中科院分区：
文献类型：
--
作者：
Roerig,SC;Loh,HH;Law,PY
百日咳毒素（PTX）在NAD+存在下催化GTP结合蛋白（G蛋白）α亚基的ADP-核糖基化。百日咳毒素还降低尿素SDS PAGE上a-亚基的电泳迁移率。PTX的这种作用被认为是毒素的一种性质，不同于其催化ADP-核糖基化的能力。然而，本报告提供了相反的证据;即，这种迁移率变化需要α亚基的ADP-核糖基化。这一结论的依据是：（1）在增加浓度的NAD+存在下，（0.026-1.3 μM），通过选择性抗血清免疫印迹测量，迁移较慢的α亚基的形成呈线性增加，（2）向孵育混合物中添加NADase完全消除了该蛋白质的形成，和（3）增加烟酰胺的浓度（50-250 mM），其抑制ADP-核糖基化，降低了较慢迁移的α-亚基的量。因此，除了PTX之外，NAD+是迁移率转变所需的，并且较慢迁移的α-亚基可能是ADP-核糖基化形式。
Pertussis toxin (PTX) catalyzes the ADP-ribosylation of the α-subunit of GTPbinding proteins (G-proteins) in the presence of NAD+. Pertussis toxin also decreases the electrophoretic mobility of the a-subunit on urea SDS PAGE. This effect of PTX has been suggested to be a property of the toxin different from its ability to catalyze ADP-ribosylation. However, the present report provides evidence to the contrary; ie, this mobility shift required the ADP-ribosylation of α-subunits. This conclusion was based on: (1) in the presence of increasing concentrations of NAD+(0.026-1.3 μM), there was a linear increase in the formation of the slower migrating α-subunit as measured by immunoblotting with selective antisera, (2) addition of NADase to the incubation mixture completely eliminated the formation of this protein, and (3) increasing concentrations of nicotinamide (50–250 mM), which inhibits ADP-ribosylation, decreased the amount of the slower migrating a-subunit. Thus, in addition to PTX, NAD+was required for the mobility shift and the slower migrating a-subunit is likely the ADP-ribosylated form.