Binding of polyamines to an autonomous domain of the regulatory subunit of protein kinase CK2 induces a conformational change in the holoenzyme - A proposed role for the kinase stimulation
Binding of polyamines to an autonomous domain of the regulatory subunit of protein kinase CK2 induces a conformational change in the holoenzyme - A proposed role for the kinase stimulation
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DOI：
10.1074/jbc.272.33.20820
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发表时间：
1997-08-15
影响因子：
4.8
通讯作者：
Cochet, C
中科院分区：
文献类型：
--
作者：
Leroy, D;Heriche, JK;Cochet, C
细胞调节蛋白激酶CK 2的方式仍然不清楚，然而，据报道，天然多胺（细胞增殖所需的细胞化合物）强烈刺激CK 2介导的许多底物的磷酸化。使用精胺类似物，我们已经表明多胺直接相互作用与CK 2 β亚基，并确定了高酸性结合位点（Asp（51）-Tyr（80））的化学特征。我们发现，从残基Asp（51）延伸到Pro（110）的分离的β亚基区域表现出与整个β亚基相似的特异性和有效的多胺结合活性。此外，Glu（60），Glu（61），β亚基的Glu（63）被3个丙氨酸残基取代导致精胺诱导的CK 2活性刺激的丧失，这与精胺结合亲和力的降低相关，热稳定性研究表明，精胺的结合诱导全酶的Tm值降低4 ℃。圆二色性分析证实了这一点，圆二色性分析表明，由精胺结合引起的CK 2 T-m值的6 ℃负移反映了激酶的构象变化。总之，这些观察结果强烈表明，这个新定义的多胺结合域参与了CK 2活性的内质网调控。
The means by which the cell regulates protein kinase CK2 remain obscure, However, natural polyamines, cellular compounds required for cell proliferation, have been reported to strongly stimulate CK2-mediated phosphorylation of a number of substrates, Using spermine analogs, we have shown that polyamines directly interact with the CK2 beta subunit, and the chemical features of the highly acidic binding site (Asp(51)-Tyr(80)) have been determined, In the present study, we show that the isolated beta subunit region extending from residue Asp(51) to Pro(110) exhibits a specific and efficient polyamine binding activity similar to that of the entire beta subunit, Moreover, the replacement of Glu(60), Glu(61), and Glu(63) of the beta subunit by 3 alanine residues leads to a loss of the spermine-induced stimulation of CK2 activity which correlates with a decrease in spermine binding affinity, Thermal stability studies indicate that the binding of spermine induces a 4 degrees C decrease of the T-m value for the holoenzyme. This was confirmed by circular dichroism analyses, which show that the 6 degrees C negative shift of the CK2 T-m value provoked by spermine binding, reflects a conformational change in the kinase. Together, these observations strongly suggest that this newly defined polyamine binding domain is involved in the intrasteric regulation of CK2 activity.