Hsp90 binds and regulates the ligand-inducible α subunit of eukaryotic translation initiation factor kinase Gcn2
Hsp90 binds and regulates the ligand-inducible α subunit of eukaryotic translation initiation factor kinase Gcn2
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DOI：
10.1128/mcb.19.12.8422
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发表时间：
1999-12-01
影响因子：
5.3
通讯作者：
Picard, D
中科院分区：
文献类型：
--
作者：
Donzé, O;Picard, D
蛋白激酶Gcn2在氨基酸缺乏时刺激酵母转录因子Gcn4的翻译。利用遗传和生化方法，我们发现Gcn2在出芽酵母酿酒酵母中受分子伴侣蛋白Hsp90的调控。具体来说，我们发现(i)几种Hsp90突变株表现出GCN4-lacZ报告质粒的组成性表达；（ii） Gcn2和Hsp90在体内和体外形成复合物；（iii） Hsp90特异性抑制剂格尔达霉素（geldanamycin）和马becin I在体外增强Gcn2与Hsp90的关联，抑制其激酶活性；（iv）在体内，macbecin I能显著降低Gcn2的水平；(v)在表达温度敏感型Hsp90突变体G170D的菌株中，Gcn2的积累和活性在限制温度下均被消除；（vi） Hsp90的伴侣蛋白Cdc37、Sti1和Sba1是氨基酸饥饿反应所必需的。综上所述，这些数据确定Gcn2是Hsp90的新靶点，Hsp90在Gcn2的成熟和调控中起着至关重要的作用。
The protein kinase Gcn2 stimulates translation of the yeast transcription factor Gcn4 upon amino acid starvation. Using genetic and biochemical approaches, we show that Gcn2 is regulated by the molecular chaperone Hsp90 in budding yeast Saccharomyces cerevisiae. Specifically, we found that (i) several Hsp90 mutant strains exhibit constitutive expression of a GCN4-lacZ reporter plasmid; (ii) Gcn2 and Hsp90 form a complex in vitro as well as in vivo; (iii) the specific inhibitors of Hsp90, geldanamycin and macbecin I, enhance the association of Gcn2 with Hsp90 and inhibit its kinase activity in vitro; (iv) in vivo, macbecin I strongly reduces the levels of Gcn2; (v) in a strain expressing the temperature-sensitive Hsp90 mutant G170D, both the accumulation and activity of Gcn2 are abolished at the restrictive temperature; and (vi) the Hsp90 cochaperones Cdc37, Sti1, and Sba1 are required for the response to amino acid starvation. Taken together, these data identify Gcn2 as a novel target for Hsp90, which plays a crucial role for the maturation and regulation of Gcn2.