scholarly journals Ribosomal ubiquitination facilitates mRNA cleavage and ribosome rescue during No-Go and Nonstop mRNA Decay

2021 ◽  
Author(s):  
Parissa C. Monem ◽  
Audrey L. Piatt ◽  
Nitin Vidyasagar ◽  
Marissa L. Glover ◽  
Thea A. Egelhofer ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Mrna Decay ◽  
Critical Role ◽  
Mrna Degradation ◽  
C Elegans ◽  
N Terminus ◽  
Nonstop Mrna Decay ◽  
Cellular Machinery ◽  
Translation Signals

During translational surveillance, ribosomes play a critical role in detecting problematic mRNAs and signaling cellular machinery to repress the offending messages. Prior work has shown that problematic mRNAs identified by two surveillance pathways (Nonstop and No-Go mRNA Decay) are detected by ribosome collisions and subsequent ribosomal ubiquitination, yet how ribosomal ubiquitination leads to repression has remained unclear. Here, we deploy C. elegans to unravel the series of coordinated events during Nonstop and No-Go mRNA Decay. We probe the metazoan SKI RNA helicase complex to uncover functionally significant residues and reveal divergence of the SKI-exosome interface. We define a functional requirement for ubiquitination on at least two ribosomal proteins during No-Go mRNA Decay, and illustrate how ubiquitination recruits the endonuclease NONU-1 via CUE domains and the ribosome rescue factor HBS-1 via its poorly characterized N-terminus. Our molecular characterization (1) underscores the importance of ribosomal ubiquitination in mRNA degradation, (2) shows similar and distinct genetic dependencies of factors in Nonstop and No-Go mRNA Decay, and (3) uncovers a conspicuous absence of distinct ribosomal stalls at No-Go mRNA Decay substrates. Our work demonstrates mechanisms by which translation signals to effectors of co-translational mRNA repression and has implications for the study of translation and ribosomal species in vivo.

mRNA degradation by processive 3′-5′ exoribonucleases in Vitro and the implications for prokaryotic mRNA decay in Vivo

1991 ◽  
Vol 221 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Robert S. McLaren ◽  
Sarah F. Newbury ◽  
Geoffrey S.C. Dance ◽  
Helen C. Causton ◽  
Christopher F. Higgins
Keyword(s):  
Mrna Decay ◽  
Mrna Degradation

scholarly journals Stress granules and processing bodies are dynamically linked sites of mRNP remodeling

2005 ◽  
Vol 169 (6) ◽  
pp. 871-884 ◽  
Author(s):  
Nancy Kedersha ◽  
Georg Stoecklin ◽  
Maranatha Ayodele ◽  
Patrick Yacono ◽  
Jens Lykke-Andersen ◽  
...  
Keyword(s):  
Mrna Decay ◽  
Stress Granules ◽  
Mrna Degradation ◽  
Processing Bodies ◽  
Eif2α Phosphorylation ◽  
Protein Components

Stress granules (SGs) are cytoplasmic aggregates of stalled translational preinitiation complexes that accumulate during stress. GW bodies/processing bodies (PBs) are distinct cytoplasmic sites of mRNA degradation. In this study, we show that SGs and PBs are spatially, compositionally, and functionally linked. SGs and PBs are induced by stress, but SG assembly requires eIF2α phosphorylation, whereas PB assembly does not. They are also dispersed by inhibitors of translational elongation and share several protein components, including Fas-activated serine/threonine phosphoprotein, XRN1, eIF4E, and tristetraprolin (TTP). In contrast, eIF3, G3BP, eIF4G, and PABP-1 are restricted to SGs, whereas DCP1a and 2 are confined to PBs. SGs and PBs also can harbor the same species of mRNA and physically associate with one another in vivo, an interaction that is promoted by the related mRNA decay factors TTP and BRF1. We propose that mRNA released from disassembled polysomes is sorted and remodeled at SGs, from which selected transcripts are delivered to PBs for degradation.

scholarly journals The Two Proteins Pat1p (Mrt1p) and Spb8p Interact In Vivo, Are Required for mRNA Decay, and Are Functionally Linked to Pab1p

2000 ◽  
Vol 20 (16) ◽  
pp. 5939-5946 ◽  
Author(s):  
Claire Bonnerot ◽  
Ronald Boeck ◽  
Bruno Lapeyre
Keyword(s):  
Mrna Decay ◽  
Essential Gene ◽  
Sharp Decrease ◽  
Degradation Pathway ◽  
Mrna Degradation ◽  
Wild Type ◽  
Specific Signal ◽  
Type Gene

ABSTRACT We report here the characterization of a bypass suppressor ofpab1Δ which leads to a fourfold stabilization of the unstable MFA2 mRNA. Cloning of the wild-type gene for that suppressor reveals that it is identical to PAT1 (YCR077c), a gene whose product was reported to interact with Top2p.PAT1 is not an essential gene, but its deletion leads to a thermosensitive phenotype. Further analysis has shown thatPAT1 is allelic with mrt1-3, a mutation previously reported to affect decapping and to bypass suppresspab1Δ, as is also the case for dcp1,spb8, and mrt3. Coimmunoprecipitation experiments show that Pat1p is associated with Spb8p. On sucrose gradients, the two proteins cosediment with fractions containing the polysomes. In the absence of Pat1p, however, Spb8p no longer cofractionates with the polysomes, while the removal of Spb8p leads to a sharp decrease in the level of Pat1p. Our results suggest that some of the factors involved in mRNA degradation could be associated with the mRNA that is still being translated, awaiting a specific signal to commit the mRNA to the degradation pathway.

scholarly journals Sequence and transmembrane topology of MEC-4, an ion channel subunit required for mechanotransduction in Caenorhabditis elegans.

1996 ◽  
Vol 133 (5) ◽  
pp. 1071-1081 ◽  
Author(s):  
C C Lai ◽  
K Hong ◽  
M Kinnell ◽  
M Chalfie ◽  
M Driscoll
Keyword(s):  
Caenorhabditis Elegans ◽  
Ion Channel ◽  
Critical Role ◽  
Comparative Sequence Analysis ◽  
Mechanical Stimuli ◽  
Transmembrane Topology ◽  
C Elegans ◽  
Carboxy Terminal

The process by which mechanical stimuli are converted into cellular responses is poorly understood, in part because key molecules in this mode of signal transduction, the mechanically gated ion channels, have eluded cloning efforts. The Caenorhabditis elegans mec-4 gene encodes a subunit of a candidate mechanosensitive ion channel that plays a critical role in touch reception. Comparative sequence analysis of C. elegans and Caenorhabditis briggsae mec-4 genes was used to initiate molecular studies that establish MEC-4 as a 768-amino acid protein that includes two hydrophobic domains theoretically capable of spanning a lipid bilayer. Immunoprecipitation of in vitro translated mec-4 protein with domain-specific anti-MEC-4 antibodies and in vivo characterization of a series of mec-4lacZ fusion proteins both support the hypothesis that MEC-4 crosses the membrane twice. The MEC-4 amino- and carboxy-terminal domains are situated in the cytoplasm and a large domain, which includes three Cys-rich regions, is extracellular. Definition of transmembrane topology defines regions that might interact with the extracellular matrix or cytoskeleton to mediate mechanical signaling.

scholarly journals Eps15 membrane-binding and -bending activity acts redundantly with Fcho1 during clathrin-mediated endocytosis

2016 ◽  
Vol 27 (17) ◽  
pp. 2675-2687 ◽  
Author(s):  
Lei Wang ◽  
Adam Johnson ◽  
Michael Hanna ◽  
Anjon Audhya
Keyword(s):  
Genetic Interaction ◽  
Critical Role ◽  
Membrane Binding ◽  
Accessory Proteins ◽  
Membrane Remodeling ◽  
Bar Domain ◽  
C Elegans ◽  
Accessory Factor

Clathrin coat assembly on membranes requires cytosolic adaptors and accessory proteins, which bridge triskeleons with the lipid bilayer and stabilize lattice architecture throughout the process of vesicle formation. In Caenorhabditis elegans, the prototypical AP-2 adaptor complex, which is activated by the accessory factor Fcho1 at the plasma membrane, is dispensable during embryogenesis, enabling us to define alternative mechanisms that facilitate clathrin-mediated endocytosis. Here we uncover a synthetic genetic interaction between C. elegans Fcho1 (FCHO-1) and Eps15 (EHS-1), suggesting that they function in a parallel and potentially redundant manner. Consistent with this idea, we find that the FCHO-1 EFC/F-BAR domain and the EHS-1 EH domains exhibit highly similar membrane-binding and -bending characteristics in vitro. Furthermore, we demonstrate a critical role for EHS-1 when FCHO-1 membrane-binding and -bending activity is specifically eliminated in vivo. Taken together, our data highlight Eps15 as an important membrane-remodeling factor, which acts in a partially redundant manner with Fcho proteins during the earliest stages of clathrin-mediated endocytosis.

scholarly journals Engineering a conserved RNA regulatory protein repurposes its biological function in vivo

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Vandita D Bhat ◽  
Kathleen L McCann ◽  
Yeming Wang ◽  
Dallas R Fonseca ◽  
Tarjani Shukla ◽  
...  
Keyword(s):  
Genome Engineering ◽  
Rna Binding ◽  
Biological Function ◽  
Rna Binding Proteins ◽  
Critical Role ◽  
Regulatory Protein ◽  
Motif Length ◽  
C Elegans ◽  
Preferential Binding

PUF (PUmilio/FBF) RNA-binding proteins recognize distinct elements. In C. elegans, PUF-8 binds to an 8-nt motif and restricts proliferation in the germline. Conversely, FBF-2 recognizes a 9-nt element and promotes mitosis. To understand how motif divergence relates to biological function, we first determined a crystal structure of PUF-8. Comparison of this structure to that of FBF-2 revealed a major difference in a central repeat. We devised a modified yeast 3-hybrid screen to identify mutations that confer recognition of an 8-nt element to FBF-2. We identified several such mutants and validated structurally and biochemically their binding to 8-nt RNA elements. Using genome engineering, we generated a mutant animal with a substitution in FBF-2 that confers preferential binding to the PUF-8 element. The mutant largely rescued overproliferation in animals that spontaneously generate tumors in the absence of puf-8. This work highlights the critical role of motif length in the specification of biological function.

scholarly journals Phosphorylation-dependent Regnase-1 release from endoplasmic reticulum is critical in IL-17 response

2019 ◽  
Vol 216 (6) ◽  
pp. 1431-1449 ◽  
Author(s):  
Hiroki Tanaka ◽  
Yasunobu Arima ◽  
Daisuke Kamimura ◽  
Yuki Tanaka ◽  
Noriyuki Takahashi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Target Genes ◽  
Inflammatory Diseases ◽  
Critical Role ◽  
Mrna Degradation ◽  
Mutant Mice ◽  
Dependent Manner ◽  
T Helper 17 ◽  
External Stimuli

Regnase-1 (also known as Zc3h12a or MCPIP-1) is an endoribonuclease involved in mRNA degradation of inflammation-associated genes. Regnase-1 is inactivated in response to external stimuli through post-translational modifications including phosphorylation, yet the precise role of phosphorylation remains unknown. Here, we demonstrate that interleukin (IL)-17 induces phosphorylation of Regnase-1 in an Act1-TBK1/IKKi–dependent manner, especially in nonhematopoietic cells. Phosphorylated Regnase-1 is released from the endoplasmic reticulum (ER) into the cytosol, thereby losing its mRNA degradation function, which leads to expression of IL-17 target genes. By using CRISPR/Cas-9 technology, we generated Regnase-1 mutant mice, in which IL-17–induced Regnase-1 phosphorylation is completely blocked. Mutant mice (Regnase-1AA/AA and Regnase-1ΔCTD/ΔCTD) were resistant to the IL-17–mediated inflammation caused by T helper 17 (Th17) cells in vivo. Thus, Regnase-1 plays a critical role in the development of IL-17–mediated inflammatory diseases via the Act1-TBK1-IKKi axis, and blockade of Regnase-1 phosphorylation sites may be promising for treatment of Th17-associated diseases.

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