Wheat germ poly(A)-binding protein increases the ATPase and the RNA helicase activity of translation initiation factors eIF4A, eIF4B, and eIF-iso4F
Wheat germ poly(A)-binding protein increases the ATPase and the RNA helicase activity of translation initiation factors eIF4A, eIF4B, and eIF-iso4F
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DOI：
10.1074/jbc.m909464199
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发表时间：
2000-06-09
影响因子：
4.8
通讯作者：
Goss, DJ
中科院分区：
文献类型：
--
作者：
Bi, XP;Goss, DJ
最近的研究表明，小麦胚芽多聚腺苷酸结合蛋白（PBBP）与翻译真核起始因子（eIF）-iso 4G和eIF 4 B相互作用，这些相互作用增加了PABP的多聚腺苷酸结合活性（Le，H.，Tanguay，R，L.，Balasta，M. L.，魏角，澳-地C.的方法，布朗宁，K.美国，梅斯，A. M.，Goss，D. J.，Gallie，D. R.等人（1997）J. Biol. Chen. 272，16247-16255）和eIF-iso 4F的帽结合活性（Wei，C. C.的方法，Balasta，M. L.，Ren，J.，和Goss，D. J.（1998）Biochemistry 37，1910-1916）。PABP与eIF-iso 4G的相互作用对（eIF 4A + eIF 4 B + eIF-iso 4F）复合物的ATP酶活性和RNA解旋酶活性有显著影响。ATP酶动力学分析表明，在poly（U）存在下，PABP可使（eIF 4A + eIF-iso 4F）复合物的参数（k（cat）/K-m）增加3.5倍，K-m降低2倍。在珠蛋白信使RNA存在下，PABP的存在使复合物（eIF 4A + eIF-iso 4F）的ATP酶活性增加了a倍。RNA解旋酶分析表明，PABP的存在下增强了起始因子复合物的RNA双链体解旋活性。这些结果表明，在翻译起始的扫描模式方面，PABP可以增强eIF 4A、eIF 4 B和eIF 4F或eIF-（iso）4F形成的复合物的mRNA扫描速率，并增加翻译速率。
Recent studies demonstrated that wheat germ poly(A)-binding protein (PBBP) interacted with translation eukaryotic initiation factor (eIF)-iso4G and eIF4B, and these interactions increased the poly(A) binding activity of PABP (Le, H., Tanguay, R, L., Balasta, M. L., Wei, C. C., Browning, K. S., Metz, A. M., Goss, D. J., and Gallie, D. R. (1997) J. Biol. Chen. 272, 16247-16255) and the cap binding activity of eIF-iso4F (Wei, C. C., Balasta, M. L., Ren, J., and Goss, D. J. (1998) Biochemistry 37, 1910-1916). We report here that the interaction between PABP and eIF-iso4G has a substantial effect on the ATPase activity and RNA helicase activity of (eIF4A + eIF4B + eIF-iso4F) complex. ATPase kinetic assays show, in the presence of poly(U), PABP can increase the parameter (k(cat)/K-m) by 3.5-fold with a 2-fold decrease of K-m for the (eIF4A + eIF-iso4F) complex. In the presence of globin messenger RNA, the ATPase activity of the complex (eIF4A + eIF-iso4F) was increased a-fold by the presence of PABP. RNA helicase assays demonstrated that the presence of PABP enhanced the RNA duplex unwinding activity of the initiation factor complex. These results suggest that, in terms of the scanning model of translation initiation, PABP may enhance the mRNA scanning rate of the complex formed by eIF4A, eIF4B, and eIF4F or eIF-(iso)4F and increase the rate of translation.