Chapter 4 Regulation of Translation by Stress Granules and Processing Bodies

Tethered interactions between the endoplasmic reticulum (ER) and other membrane-bound organelles allow for efficient transfer of ions and/or macromolecules and provide a platform for organelle fission. Here, we describe an unconventional interface between membraneless ribonucleoprotein granules, such as processing bodies (P-bodies, or PBs) and stress granules, and the ER membrane. We found that PBs are tethered at molecular distances to the ER in human cells in a tunable fashion. ER-PB contact and PB biogenesis were modulated by altering PB composition, ER shape, or ER translational capacity. Furthermore, ER contact sites defined the position where PB and stress granule fission occurs. We thus suggest that the ER plays a fundamental role in regulating the assembly and disassembly of membraneless organelles.

Download Full-text

Faculty Opinions recommendation of Stress granules and processing bodies are dynamically linked sites of mRNP remodeling.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1022683.325253 ◽

2005 ◽

Author(s):

Arlen Johnson

Keyword(s):

Stress Granules ◽

Processing Bodies

Download Full-text

The yeast Cbk1 kinase regulates mRNA localization via the mRNA-binding protein Ssd1

The Journal of Cell Biology ◽

10.1083/jcb.201011061 ◽

2011 ◽

Vol 192 (4) ◽

pp. 583-598 ◽

Cited By ~ 37

Author(s):

Cornelia Kurischko ◽

Hong Kyung Kim ◽

Venkata K. Kuravi ◽

Juliane Pratzka ◽

Francis C. Luca

Keyword(s):

Binding Protein ◽

Cellular Stress ◽

Stress Granules ◽

Polarized Growth ◽

Cell Integrity ◽

Processing Bodies ◽

P Bodies ◽

Mrna Binding Protein ◽

Cortical Localization ◽

Mrna Binding

The mRNA-binding protein Ssd1 is a substrate for the Saccharomyces cerevisiae LATS/NDR orthologue Cbk1, which controls polarized growth, cell separation, and cell integrity. We discovered that most Ssd1 localizes diffusely within the cytoplasm, but some transiently accumulates at sites of polarized growth. Cbk1 inhibition and cellular stress cause Ssd1 to redistribute to mRNA processing bodies (P-bodies) and stress granules, which are known to repress translation. Ssd1 recruitment to P-bodies is independent of mRNA binding and is promoted by the removal of Cbk1 phosphorylation sites. SSD1 deletion severely impairs the asymmetric localization of the Ssd1-associated mRNA, SRL1. Expression of phosphomimetic Ssd1 promotes polarized localization of SRL1 mRNA, whereas phosphorylation-deficient Ssd1 causes constitutive localization of SRL1 mRNA to P-bodies and causes cellular lysis. These data support the model that Cbk1-mediated phosphorylation of Ssd1 promotes the cortical localization of Ssd1–mRNA complexes, whereas Cbk1 inhibition, cellular stress, and Ssd1 dephosphorylation promote Ssd1–mRNA interactions with P-bodies and stress granules, leading to translational repression.

Download Full-text

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

The Journal of Cell Biology ◽

10.1083/jcb.200502088 ◽

2005 ◽

Vol 169 (6) ◽

pp. 871-884 ◽

Cited By ~ 858

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.

Download Full-text