Internal Loop/Bulge and Hairpin Loop of the Iron-Responsive Element of Ferritin mRNA Contribute to Maximal Iron Regulatory Protein 2 Binding and Translational Regulation in the Iso-iron-responsive Element/Iso-iron Regulatory Protein Family

Biochemistry ◽  
2000 ◽  
Vol 39 (20) ◽  
pp. 6235-6242 ◽  
Author(s):  
Yaohuang Ke ◽  
Hanna Sierzputowska-Gracz ◽  
Zofia Gdaniec ◽  
Elizabeth C. Theil
Keyword(s):  
Translational Regulation ◽  
Regulatory Protein ◽  
Protein Family ◽  
Iron Regulatory Protein ◽  
Hairpin Loop ◽  
Internal Loop ◽  
Iron Responsive Element ◽  
Responsive Element

scholarly journals Novel Translational Control through an Iron-Responsive Element by Interaction of Multifunctional Protein YB-1 and IRP2

2002 ◽  
Vol 22 (18) ◽  
pp. 6375-6383 ◽  
Author(s):  
Megumi Ashizuka ◽  
Takao Fukuda ◽  
Takanori Nakamura ◽  
Kanemitsu Shirasuna ◽  
Kazuhiro Iwai ◽  
...  
Keyword(s):  
Translational Control ◽  
Ribosomal Proteins ◽  
Translational Regulation ◽  
Regulatory Protein ◽  
Direct Interaction ◽  
In Vitro Translation ◽  
High Concentration ◽  
Iron Responsive Element ◽  
Responsive Element

ABSTRACT The eukaryotic Y-box-binding protein YB-1 functions in various biological processes, including DNA repair, cell proliferation, and transcriptional and translational controls. To gain further insight into how human YB-1 plays its role in pleiotropic functions, we here used two-hybrid screenings to identify partners of this protein; the results showed that YB-1 itself, iron-regulatory protein 2 (IRP2), and five ribosomal proteins each served as partners to YB-1. We then examined the biological effect of the interaction of YB-1 and IRP2 on translational regulation. Both in vitro binding and coimmunoprecipitation assays showed the direct interaction of YB-1 and IRP2 in the presence of a high concentration of iron. RNA gel shift assays showed that YB-1 reduced the formation of the IRP2-mRNA complex when the iron-responsive element of the ferritin mRNA 5′ untranslated region (UTR) was used as a probe. By using an in vitro translation assay using luciferase mRNA ligated to the ferritin mRNA 5′UTR as a reporter construct, we showed that both YB-1 and IRP2 inhibited the translation of the mRNA. However, coadministration of YB-1 and IRP2 proteins abrogated the inhibition of protein synthesis by each protein. An In vivo coimmunoprecipitation assay showed that IRP2 bound to YB-1 in the presence of iron and a proteasome inhibitor. The direct interaction of YB-1 and IRP2 provides the first evidence of the involvement of YB-1 in the translational regulation of an iron-related protein.

scholarly journals Loops and Bulge/Loops in Iron-responsive Element Isoforms Influence Iron Regulatory Protein Binding

1998 ◽  
Vol 273 (37) ◽  
pp. 23637-23640 ◽  
Author(s):  
Yaohuang Ke ◽  
Jingyang Wu ◽  
Elizabeth A. Leibold ◽  
William E. Walden ◽  
Elizabeth C. Theil
Keyword(s):  
Protein Binding ◽  
Regulatory Protein ◽  
Iron Regulatory Protein ◽  
Iron Responsive Element ◽  
Responsive Element
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