scholarly journals Staufen1 and UPF1 exert opposite actions on the replacement of the nuclear cap-binding complex by eIF4E at the 5′ end of mRNAs

2019 ◽  
Vol 47 (17) ◽  
pp. 9313-9328 ◽  
Author(s):  
Kwon Jeong ◽  
Incheol Ryu ◽  
Joori Park ◽  
Hyun Jung Hwang ◽  
Hongseok Ha ◽  
...  

Abstract Newly synthesized mRNAs are exported from the nucleus to cytoplasm with a 5′-cap structure bound by the nuclear cap-binding complex (CBC). During or after export, the CBC should be properly replaced by cytoplasmic cap-binding protein eIF4E for efficient protein synthesis. Nonetheless, little is known about how the replacement takes place. Here, we show that double-stranded RNA-binding protein staufen1 (STAU1) promotes efficient replacement by facilitating an association between the CBC–importin α complex and importin β. Our transcriptome-wide analyses and artificial tethering experiments also reveal that the replacement occurs more efficiently when an mRNA associates with STAU1. This event is inhibited by a key nonsense-mediated mRNA decay factor, UPF1, which directly interacts with STAU1. Furthermore, we find that cellular apoptosis that is induced by ionizing radiation is accompanied by inhibition of the replacement via increased association between STAU1 and hyperphosphorylated UPF1. Altogether, our data highlight the functional importance of STAU1 and UPF1 in the course of the replacement of the CBC by eIF4E, adding a previously unappreciated layer of post-transcriptional gene regulation.

2013 ◽  
Vol 87 (24) ◽  
pp. 13409-13421 ◽  
Author(s):  
J. E. Petrillo ◽  
P. A. Venter ◽  
J. R. Short ◽  
R. Gopal ◽  
S. Deddouche ◽  
...  

2016 ◽  
Vol 311 (6) ◽  
pp. C874-C883 ◽  
Author(s):  
Yan Xu ◽  
Jie Chen ◽  
Lan Xiao ◽  
Hee Kyoung Chung ◽  
Yuan Zhang ◽  
...  

The RNA-binding protein HuR is crucial for normal intestinal mucosal regeneration by modulating the stability and translation of target mRNAs, but the exact mechanism underlying HuR trafficking between the cytoplasm and nucleus remains largely unknown. Here we report a novel function of transcription factor JunD in the regulation of HuR subcellular localization through the control of importin-α1 expression in intestinal epithelial cells (IECs). Ectopically expressed JunD specifically inhibited importin-α1 at the transcription level, and this repression is mediated via interaction with CREB-binding site that was located at the proximal region of importin-α1 promoter. Reduction in the levels of importin-α1 by JunD increased cytoplasmic levels of HuR, although it failed to alter whole cell HuR levels. Increased levels of endogenous JunD by depleting cellular polyamines also inhibited importin-α1 expression and increased cytoplasmic HuR levels, whereas JunD silencing rescued importin-α1 expression and enhanced HuR nuclear translocation in polyamine-deficient cells. Moreover, importin-α1 silencing protected IECs against apoptosis, which was prevented by HuR silencing. These results indicate that JunD regulates HuR subcellular distribution by downregulating importin-α1, thus contributing to the maintenance of gut epithelium homeostasis.


Virology ◽  
1993 ◽  
Vol 195 (2) ◽  
pp. 732-744 ◽  
Author(s):  
Hao Yuwen ◽  
Josephine H. Cox ◽  
Jonathan W. Yewdell ◽  
Jack R. Bennink ◽  
Bernard Moss

2020 ◽  
Vol 78 (1) ◽  
Author(s):  
Sajad Rashidi ◽  
Kurosh Kalantar ◽  
Celia Fernandez-Rubio ◽  
Enayat Anvari ◽  
Paul Nguewa ◽  
...  

ABSTRACT Leishmaniasis includes a broad spectrum of pathological outcomes in humans caused by protozoan parasites from the genus Leishmania. In recent years, proteomic techniques have introduced novel proteins with critical functions in Leishmania parasites. Based on our report of a Chitin binding protein (CBP) in our previous immunoproteomic study, this article suggests that CBP might be an RNA binding protein (RBP) in Leishmania parasites. RBPs, as key regulatory factors, have a role in post-transcriptional gene regulation. The presence of RBPs in Leishmania parasites has not been considered so far; however, this study aims to open a new venue regarding RBPs in Leishmania parasites. Confirming CBP as an RBP in Leishmania parasites, exploring other RBPs and their functions might lead to interesting issues in leishmaniasis. In fact, due to the regulatory role of RBPs in different diseases including cancers and their further classification as therapeutic targets, the emerging evaluation of CBP and RBPs from Leishmania parasites may allow the discovery of novel and effective drugs against leishmaniasis.


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