Interaction of the Ras-related protein associated with diabetes rad and the putative tumor metastasis suppressor NM23 provides a novel mechanism of GTPase regulation.
Interaction of the Ras-related protein associated with diabetes rad and the putative tumor metastasis suppressor NM23 provides a novel mechanism of GTPase regulation.
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DOI：
10.1073/pnas.96.26.14911
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发表时间：
1999-12
影响因子：
11.1
通讯作者：
Jianhua Zhu;Yu-Hua Tseng;J. Kantor;Christopher J. Rhodes;Bruce R. Zetter;J. Moyers;C. Kahn
中科院分区：
文献类型：
--
作者：
Jianhua Zhu;Yu-Hua Tseng;J. Kantor;Christopher J. Rhodes;Bruce R. Zetter;J. Moyers;C. Kahn
Rad是一类新的Ras相关GTP酶的原型成员。Rad的GTP酶激活蛋白（GAP）的纯化揭示了nm 23，一个假定的肿瘤转移抑制因子和果蝇的发育基因。针对nm 23的抗体从人骨骼肌胞质溶胶中耗尽Rad-GAP活性，并且细菌表达的nm 23重建活性。nm 23差距活性是特异性的Rad，是不存在的与S105 N推定显性负突变体的Rad，并减少与nm 23的突变。在ATP存在下，GDP·Rad也通过nm 23的核苷二磷酸（NDP）激酶活性重新转化为GTP·Rad。同时，Rad通过增强nm 23的NDP激酶活性和降低其自磷酸化来调节nm 23。黑色素瘤细胞转染野生型拉德，但不是S105 N-Rad，表现出增强的DNA合成的血清反应，这种效果与nm 23的共表达丢失。因此，nm 23和拉德的相互作用提供了一个潜在的新的机制，双向，双分子调节，其中nm 23刺激GTP水解和GTP负载的拉德，而拉德调节nm 23的活性。这种相互作用可能在Rad调节糖代谢以及nm 23调节肿瘤转移和发育中发挥重要作用。
Rad is the prototypic member of a new class of Ras-related GTPases. Purification of the GTPase-activating protein (GAP) for Rad revealed nm23, a putative tumor metastasis suppressor and a development gene in Drosophila. Antibodies against nm23 depleted Rad-GAP activity from human skeletal muscle cytosol, and bacterially expressed nm23 reconstituted the activity. The GAP activity of nm23 was specific for Rad, was absent with the S105N putative dominant negative mutant of Rad, and was reduced with mutations of nm23. In the presence of ATP, GDP.Rad was also reconverted to GTP.Rad by the nucleoside diphosphate (NDP) kinase activity of nm23. Simultaneously, Rad regulated nm23 by enhancing its NDP kinase activity and decreasing its autophosphorylation. Melanoma cells transfected with wild-type Rad, but not the S105N-Rad, showed enhanced DNA synthesis in response to serum; this effect was lost with coexpression of nm23. Thus, the interaction of nm23 and Rad provides a potential novel mechanism for bidirectional, bimolecular regulation in which nm23 stimulates both GTP hydrolysis and GTP loading of Rad whereas Rad regulates activity of nm23. This interaction may play important roles in the effects of Rad on glucose metabolism and the effects of nm23 on tumor metastasis and developmental regulation.