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Bimodal mechanism of mRNA association with the endoplasmic reticulum (ER)
Author(s) -
Jagannathan Sujatha,
Chen Qiang,
Reid David,
Nicchitta Christopher
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb51
Subject(s) - messenger rna , endoplasmic reticulum , p bodies , microbiology and biotechnology , ribosome , signal peptide , biology , translation (biology) , messenger rnp , secretory protein , chemistry , rna , gene , biochemistry , peptide sequence
mRNA localization is vital for the spatiotemporal control of cellular protein synthesis. Partitioning mRNAs between cytosol and ER is the most prominent mRNA localization process in cells, operating on the entire mRNA transcriptome. mRNAs encoding secretory pathway proteins are recruited to the ER membrane via the signal recognition particle (SRP) pathway, where mRNA binding to ER requires a translating ribosome. Previously, we have shown that mRNAs encoding ER‐resident proteins display ribosome‐independent interactions with ER, suggesting multiple pathways to regulate mRNA localization to ER. Here, we subjected microsomes derived from plasmacytoma cells to high salt/EDTA, which releases membrane‐bound ribosomes. We then analyzed the fraction of mRNA released to assess the interactions of candidate mRNAs encoding either ER resident proteins (mRNA Res ) or secretory pathway cargo proteins (mRNA Cargo ) to the ER. While mRNA Res are resistant to extraction by high salt/EDTA, mRNA Cargo are readily released. These results indicate that at least two modes of mRNA attachment to the ER are possible, and can be distinguished by the requirement for intact ribosome. As both cohorts of mRNAs encode proteins with N‐terminal signal peptide, these findings suggest that the SRP pathway may serve a primary function in directing mRNA car to ER, while additional mechanisms could direct ER localization of mRNA Res . NIH GM077382.