scholarly journals How RNA-Binding Proteins Interact with RNA: Molecules and Mechanisms

2020 ◽  
Vol 78 (1) ◽  
pp. 9-29 ◽  
Author(s):  
Meredith Corley ◽  
Margaret C. Burns ◽  
Gene W. Yeo
eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Raeann Goering ◽  
Laura I Hudish ◽  
Bryan B Guzman ◽  
Nisha Raj ◽  
Gary J Bassell ◽  
...  

The sorting of RNA molecules to subcellular locations facilitates the activity of spatially restricted processes. We have analyzed subcellular transcriptomes of FMRP-null mouse neuronal cells to identify transcripts that depend on FMRP for efficient transport to neurites. We found that these transcripts contain an enrichment of G-quadruplex sequences in their 3′ UTRs, suggesting that FMRP recognizes them to promote RNA localization. We observed similar results in neurons derived from Fragile X Syndrome patients. We identified the RGG domain of FMRP as important for binding G-quadruplexes and the transport of G-quadruplex-containing transcripts. Finally, we found that the translation and localization targets of FMRP were distinct and that an FMRP mutant that is unable to bind ribosomes still promoted localization of G-quadruplex-containing messages. This suggests that these two regulatory modes of FMRP may be functionally separated. These results provide a framework for the elucidation of similar mechanisms governed by other RNA-binding proteins.


2021 ◽  
Author(s):  
Alexandre Desroches ◽  
Jean-Bernard Denault

Apoptosis is a regulated form of cell death essential to the removal of unwanted cells. At its core, a family of cysteine peptidases named caspases cleaves key proteins allowing cell death to occur. To do so, each caspase catalytic pocket recognizes preferred amino acid sequences resulting in proteolysis, but some also use exosites to select and cleave important proteins efficaciously. Such exosites have been found in a few caspases, notably caspase-7 that has a lysine patch (K38KKK) that binds RNA which acts as a bridge to RNA-binding proteins favoring proximity between the peptidase and its substrates resulting in swifter cleavage. Although caspase-7 interaction with RNA has been identified, in-depth characterization of this interaction is lacking. In this study, using in vitro cleavage assays, we determine that RNA concentration and length affect the cleavage of RNA-binding proteins. Additionally, using binding assays and RNA sequencing, we found that caspase-7 binds RNA molecules regardless of their type, sequence, or structure. Moreover, we demonstrate that the N-terminal peptide of caspase-7 reduces the affinity of the peptidase for RNA which translates into slower cleavages of RNA-binding proteins. Finally, employing engineered heterodimers, we show that a caspase-7 dimer can use both exosites simultaneously to increase its affinity to RNA because a heterodimer with only one exosite has reduced affinity for RNA and cleavage efficacy. These findings shed light on a mechanism that furthers substrate recognition by caspases and provides potential insight into its regulation during apoptosis.


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