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Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1

Background: RNA binding proteins play crucial role in determining if a given mRNA will be translated, stored, or degraded. Sbp1 is an RGG-motif containing protein that is implicated in affecting mRNA decapping and translation. Sbp1 represses translation by binding eIF4G1 through its RGG-motif and ac...

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Autores principales: Bhatter, Nupur, Iyyappan, Rajan, Mohanan, Gayatri, Rajyaguru, Purusharth I
Formato: Online Artículo Texto
Lenguaje:English
Publicado: F1000 Research Limited 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7059846/
https://www.ncbi.nlm.nih.gov/pubmed/32175478
http://dx.doi.org/10.12688/wellcomeopenres.14709.3
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author Bhatter, Nupur
Iyyappan, Rajan
Mohanan, Gayatri
Rajyaguru, Purusharth I
author_facet Bhatter, Nupur
Iyyappan, Rajan
Mohanan, Gayatri
Rajyaguru, Purusharth I
author_sort Bhatter, Nupur
collection PubMed
description Background: RNA binding proteins play crucial role in determining if a given mRNA will be translated, stored, or degraded. Sbp1 is an RGG-motif containing protein that is implicated in affecting mRNA decapping and translation. Sbp1 represses translation by binding eIF4G1 through its RGG-motif and activates decapping when overexpressed. In this report, we have assessed the genetic interaction of Sbp1 with decapping activators such as Dhh1, Pat1, and Scd6. We have further analyzed the importance of different domains and specific conserved residues of Sbp1 in its ability to cause over-expression mediated growth defect. Method: Sequence alignment was performed to identify conserved aromatic residues to be mutated. Using site-directed mutagenesis several point mutations and domain deletions were created in Sbp1 expressed under a galactose-inducible promoter. The mutants were tested for their ability to cause growth defect upon over-expression. The ability of Sbp1 to affect over-expression mediated growth defect of other decapping activators was tested using growth assay. Live cell imaging was done to study localization of Sbp1 and its RRM-deletion mutants to RNA granules upon glucose starvation. Results: Mutation of several aromatic residues in the RGG-motif and that of the phosphorylation sites in the RRM domain of Sbp1 did not affect the growth defect phenotype. Deletion of another eIF4G1-binding RGG-motif protein Scd6 does not affect the ability of Sbp1 to cause growth defect. Moreover, absence of Sbp1 did not affect the growth defect phenotypes observed upon overexpression of decapping activators Dhh1 and Pat1. Strikingly deletion of both the RRM domains (RRM1 and RRM2) and not the RNP motifs within them compromised the growth defect phenotype. Sbp1 mutant lacking both RRM1 and RRM2 was highly defective in localizing to RNA granules.   Conclusion: This study identifies an important role of RRM domains independent of the RNP motif in Sbp1 function.
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spelling pubmed-70598462020-03-12 Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1 Bhatter, Nupur Iyyappan, Rajan Mohanan, Gayatri Rajyaguru, Purusharth I Wellcome Open Res Research Article Background: RNA binding proteins play crucial role in determining if a given mRNA will be translated, stored, or degraded. Sbp1 is an RGG-motif containing protein that is implicated in affecting mRNA decapping and translation. Sbp1 represses translation by binding eIF4G1 through its RGG-motif and activates decapping when overexpressed. In this report, we have assessed the genetic interaction of Sbp1 with decapping activators such as Dhh1, Pat1, and Scd6. We have further analyzed the importance of different domains and specific conserved residues of Sbp1 in its ability to cause over-expression mediated growth defect. Method: Sequence alignment was performed to identify conserved aromatic residues to be mutated. Using site-directed mutagenesis several point mutations and domain deletions were created in Sbp1 expressed under a galactose-inducible promoter. The mutants were tested for their ability to cause growth defect upon over-expression. The ability of Sbp1 to affect over-expression mediated growth defect of other decapping activators was tested using growth assay. Live cell imaging was done to study localization of Sbp1 and its RRM-deletion mutants to RNA granules upon glucose starvation. Results: Mutation of several aromatic residues in the RGG-motif and that of the phosphorylation sites in the RRM domain of Sbp1 did not affect the growth defect phenotype. Deletion of another eIF4G1-binding RGG-motif protein Scd6 does not affect the ability of Sbp1 to cause growth defect. Moreover, absence of Sbp1 did not affect the growth defect phenotypes observed upon overexpression of decapping activators Dhh1 and Pat1. Strikingly deletion of both the RRM domains (RRM1 and RRM2) and not the RNP motifs within them compromised the growth defect phenotype. Sbp1 mutant lacking both RRM1 and RRM2 was highly defective in localizing to RNA granules.   Conclusion: This study identifies an important role of RRM domains independent of the RNP motif in Sbp1 function. F1000 Research Limited 2021-09-17 /pmc/articles/PMC7059846/ /pubmed/32175478 http://dx.doi.org/10.12688/wellcomeopenres.14709.3 Text en Copyright: © 2021 Bhatter N et al. https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Bhatter, Nupur
Iyyappan, Rajan
Mohanan, Gayatri
Rajyaguru, Purusharth I
Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title_full Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title_fullStr Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title_full_unstemmed Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title_short Exploring the role of RRM domains and conserved aromatic residues in RGG motif  of eIF4G-binding translation repressor protein Sbp1
title_sort exploring the role of rrm domains and conserved aromatic residues in rgg motif  of eif4g-binding translation repressor protein sbp1
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7059846/
https://www.ncbi.nlm.nih.gov/pubmed/32175478
http://dx.doi.org/10.12688/wellcomeopenres.14709.3
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