Solution Structure and RNA Interactions of the RNA Recognition Motif from Eukaryotic Translation Initiation Factor 4B†

Biochemistry ◽  
2003 ◽  
Vol 42 (30) ◽  
pp. 8966-8975 ◽  
Author(s):  
Keiran Fleming ◽  
Jamie Ghuman ◽  
Xuemei Yuan ◽  
Peter Simpson ◽  
Andrea Szendröi ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Solution Structure ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Recognition Motif ◽  
Eukaryotic Translation Initiation

scholarly journals The C-Terminal Region of Eukaryotic Translation Initiation Factor 3a (eIF3a) Promotes mRNA Recruitment, Scanning, and, Together with eIF3j and the eIF3b RNA Recognition Motif, Selection of AUG Start Codons

2010 ◽  
Vol 30 (18) ◽  
pp. 4415-4434 ◽  
Author(s):  
Wen-Ling Chiu ◽  
Susan Wagner ◽  
Anna Herrmannová ◽  
Laxminarayana Burela ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Recognition Motif ◽  
Terminal Domain ◽  
Eukaryotic Translation Initiation

ABSTRACT The C-terminal domain (CTD) of the a/Tif32 subunit of budding yeast eukaryotic translation initiation factor 3 (eIF3) interacts with eIF3 subunits j/Hcr1 and b/Prt1 and can bind helices 16 to 18 of 18S rRNA, suggesting proximity to the mRNA entry channel of the 40S subunit. We have identified substitutions in the conserved Lys-Glu-Arg-Arg (KERR) motif and in residues of the nearby box6 element of the a/Tif32 CTD that impair mRNA recruitment by 43S preinitiation complexes (PICs) and confer phenotypes indicating defects in scanning and start codon recognition. The normally dispensable CTD of j/Hcr1 is required for its binding to a/Tif32 and to mitigate the growth defects of these a/Tif32 mutants, indicating physical and functional interactions between these two domains. The a/Tif32 CTD and the j/Hcr1 N-terminal domain (NTD) also interact with the RNA recognition motif (RRM) in b/Prt1, and mutations in both subunits that disrupt their interactions with the RRM increase leaky scanning of an AUG codon. These results, and our demonstration that the extreme CTD of a/Tif32 binds to Rps2 and Rps3, lead us to propose that the a/Tif32 CTD directly stabilizes 43S subunit-mRNA interaction and that the b/Prt1-RRM-j/Hcr1-a/Tif32-CTD module binds near the mRNA entry channel and regulates the transition between scanning-conducive and initiation-competent conformations of the PIC.

scholarly journals RNA Recognition Motif 2 of Yeast Pab1p Is Required for Its Functional Interaction with Eukaryotic Translation Initiation Factor 4G

1998 ◽  
Vol 18 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Steven H. Kessler ◽  
Alan B. Sachs
Keyword(s):  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Eukaryotic Translation ◽  
Recognition Motif ◽  
Amino Acid Region ◽  
Eukaryotic Translation Initiation

ABSTRACT The eukaryotic mRNA 3′ poly(A) tail and its associated poly(A)-binding protein (Pab1p) are important regulators of gene expression. One role for this complex in the yeast Saccharomyces cerevisiae is in translation initiation through an interaction with a 115-amino-acid region of the translation initiation factor eIF4G. The eIF4G-interacting domain of Pab1p was mapped to its second RNA recognition motif (RRM2) in an in vitro binding assay. Moreover, RRM2 of Pab1p was required for poly(A) tail-dependent translation in yeast extracts. An analysis of a site-directed Pab1p mutation which bound to eIF4G but did not stimulate translation of uncapped, polyadenylated mRNA suggested additional Pab1p-dependent events during translation initiation. These results support the model that the association of RRM2 of yeast Pab1p with eIF4G is a prerequisite for the poly(A) tail to stimulate the translation of mRNA in vitro.

scholarly journals Requirement of RNA Binding of Mammalian Eukaryotic Translation Initiation Factor 4GI (eIF4GI) for Efficient Interaction of eIF4E with the mRNA Cap

2008 ◽  
Vol 29 (6) ◽  
pp. 1661-1669 ◽  
Author(s):  
Akiko Yanagiya ◽  
Yuri V. Svitkin ◽  
Shoichiro Shibata ◽  
Satoshi Mikami ◽  
Hiroaki Imataka ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Rna Binding ◽  
Binding Activity ◽  
Translation Initiation Factor ◽  
Scaffolding Protein ◽  
Initiation Factor ◽  
Rna Recognition Motif ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation

ABSTRACT Eukaryotic mRNAs possess a 5′-terminal cap structure (cap), m7GpppN, which facilitates ribosome binding. The cap is bound by eukaryotic translation initiation factor 4F (eIF4F), which is composed of eIF4E, eIF4G, and eIF4A. eIF4E is the cap-binding subunit, eIF4A is an RNA helicase, and eIF4G is a scaffolding protein that bridges between the mRNA and ribosome. eIF4G contains an RNA-binding domain, which was suggested to stimulate eIF4E interaction with the cap in mammals. In Saccharomyces cerevisiae, however, such an effect was not observed. Here, we used recombinant proteins to reconstitute the cap binding of the mammalian eIF4E-eIF4GI complex to investigate the importance of the RNA-binding region of eIF4GI for cap interaction with eIF4E. We demonstrate that chemical cross-linking of eIF4E to the cap structure is dramatically enhanced by eIF4GI fragments possessing RNA-binding activity. Furthermore, the fusion of RNA recognition motif 1 (RRM1) of the La autoantigen to the N terminus of eIF4GI confers enhanced association between the cap structure and eIF4E. These results demonstrate that eIF4GI serves to anchor eIF4E to the mRNA and enhance its interaction with the cap structure.

scholarly journals The RNA Recognition Motif of Eukaryotic Translation Initiation Factor 3g (eIF3g) Is Required for Resumption of Scanning of Posttermination Ribosomes for Reinitiation on GCN4 and Together with eIF3i Stimulates Linear Scanning

2010 ◽  
Vol 30 (19) ◽  
pp. 4671-4686 ◽  
Author(s):  
Lucie Cuchalová ◽  
Tomáš Kouba ◽  
Anna Herrmannová ◽  
István Dányi ◽  
Wen-ling Chiu ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Single Point Mutation ◽  
Rna Recognition Motif ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
Linear Scanning

ABSTRACT Recent reports have begun unraveling the details of various roles of individual eukaryotic translation initiation factor 3 (eIF3) subunits in translation initiation. Here we describe functional characterization of two essential Saccharomyces cerevisiae eIF3 subunits, g/Tif35 and i/Tif34, previously suggested to be dispensable for formation of the 48S preinitiation complexes (PICs) in vitro. A triple-Ala substitution of conserved residues in the RRM of g/Tif35 (g/tif35-KLF) or a single-point mutation in the WD40 repeat 6 of i/Tif34 (i/tif34-Q258R) produces severe growth defects and decreases the rate of translation initiation in vivo without affecting the integrity of eIF3 and formation of the 43S PICs in vivo. Both mutations also diminish induction of GCN4 expression, which occurs upon starvation via reinitiation. Whereas g/tif35-KLF impedes resumption of scanning for downstream reinitiation by 40S ribosomes terminating at upstream open reading frame 1 (uORF1) in the GCN4 mRNA leader, i/tif34-Q258R prevents full GCN4 derepression by impairing the rate of scanning of posttermination 40S ribosomes moving downstream from uORF1. In addition, g/tif35-KLF reduces processivity of scanning through stable secondary structures, and g/Tif35 specifically interacts with Rps3 and Rps20 located near the ribosomal mRNA entry channel. Together these results implicate g/Tif35 and i/Tif34 in stimulation of linear scanning and, specifically in the case of g/Tif35, also in proper regulation of the GCN4 reinitiation mechanism.

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