Misfolded polypeptides are selectively recognized and transported toward aggresomes by a CED complex

Park, Joori; Park, Yeonkyoung; Ryu, Incheol; Choi, Mi Hyun; Oh, Nara; Kim, Kyutae; Kim, Kyoung Mi; Choe, Joong-Seon; Lee, Cheolju; Baik, Ja Hyun; Kim, Yoon Ki

doi:10.1038/ncomms15730

Cited by 37 publications

(63 citation statements)

References 67 publications

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“…In summary, in this section we tested the effect of different pharmacological perturbations. We also confirmed here that the expression of the labelled tracer (Synphilin1) is not the main driving force for clustering, consistent with the previous characterization that the tracer labels aggregates that are mostly composed of misfolded polypeptides (JA, 2006; Meriin et al, 2012; Park et al, 2017; Tanaka et al, 2004). We find that the theoretical model holds robustly under different drug treatments that globally affect protein quality control: a drug that reduces global protein synthesis, thereby reducing the concentration of misfolded polypeptides is found to reduce super-saturation (i.e.…”

Section: Resultssupporting

confidence: 91%

A first order phase transition mechanism underlies protein aggregation in mammalian cells

Narayanan

Meriin

Andrews

et al. 2019

eLife

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The formation of misfolded protein aggregates is a hallmark of neurodegenerative diseases. The aggregate formation process exhibits an initial lag phase when precursor clusters spontaneously assemble. However, most experimental assays are blind to this lag phase. We develop a quantitative assay based on super-resolution imaging in fixed cells and light sheet imaging of living cells to study the early steps of aggregation in mammalian cells. We find that even under normal growth conditions mammalian cells have precursor clusters. The cluster size distribution is precisely that expected for a so-called super-saturated system in first order phase transition. This means there exists a nucleation barrier, and a critical size above which clusters grow and mature. Homeostasis is maintained through a Szilard model entailing the preferential clearance of super-critical clusters. We uncover a role for a putative chaperone (RuvBL) in this disassembly of large clusters. The results indicate early aggregates behave like condensates.Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).

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Section: Resultssupporting

confidence: 91%

A first order phase transition mechanism underlies protein aggregation in mammalian cells

Narayanan

Meriin

Andrews

et al. 2019

eLife

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“…Mass spectrometry analysis revealed that the ubiquitin molecules are expressed from the UBC (polyubiquitine C) locus (Supplemental Figure 9). In addition, recent studies have shown that the eukaryotic translation elongation factor 1α (eEF1α) forms a CTIF-eEF1A1-DCTN1 complex to facilitate the aggresomal targeting of misfolded polypeptides (Park et al , 2017). We found that the levels of eEF1α in Ant1-overexpressing cells are unchanged in RIPA (1% Triton X-100, 0.1% SDS)-extracted, and slightly increased in SDS/urea (5% SDS, 8 M urea) -extracted cell lysates (Figure 7C).…”

Section: Resultsmentioning

confidence: 99%

Mitochondrial carrier protein overloading and misfolding induce aggresomes and proteostatic adaptations in the cytosol

Liu

Wang

Coyne

et al. 2019

MBoC

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Previous studies in yeast showed that mitochondrial stressors not directly targeting the protein import machinery can cause mitochondrial precursor overaccumulation stress (mPOS) in the cytosol independent of bioenergetics. Here, we demonstrate mPOS and stress responses in human cells. We show that overloading of mitochondrial membrane carrier, but not matrix proteins, is sufficient to induce cytosolic aggresomes and apoptosis. The aggresomes appear to triage unimported mitochondrial proteins. Interestingly, expression of highly unstable mutant variants of the mitochondrial carrier protein, Ant1, also induces aggresomes despite a greater than 20-fold reduction in protein level compared to wild type. Thus, overloading of the protein import machinery, rather than protein accumulation, is critical for aggresome induction. The data suggest that the import of mitochondrial proteins is saturable and that the cytosol is limited in degrading unimported mitochondrial proteins. In addition, we found that EGR1, eEF1a, and ubiquitin C are up-regulated by Ant1 overloading. These proteins are known to promote autophagy, protein targeting to aggresomes, and the processing of protein aggregates, respectively. Finally, we found that overexpression of the misfolded variants of Ant1 induces additional cytosolic responses including proteasomal activation. In summary, our work captured a profound effect of unimported mitochondrial proteins on cytosolic proteostasis and revealed multiple anti-mPOS mechanisms in human cells.

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“…HeLa cells were grown in DMEM supplemented with 10% (v/v) fetal bovine serum and 1% (v/v) penicillin/streptomycin solution (all from GE Healthcare Korea, Seoul, South Korea). The cells were transiently transfected with the plasmids or 100 mM final synthetic siRNAs (GenePharma, Shanghai, China) by using Lipofectamine 2000 (Thermo Fisher Scientific) or Oligofectamine (Thermo Fisher Scientific), respectively (29)(30)(31)(32). Total-cell RNA and protein were prepared as previously described (28,33).…”

Section: Cell Culture and Transfectionmentioning

confidence: 99%

“…Polysome fractionations with cytoplasmic extracts of cells (three 150-mm culture dishes per sample) were performed as previously described (29,32,33). Before harvesting, the cells were either nonirradiated or irradiated with UVC (25 J/m 2 ) and incubated for 2 h. Total-cell RNAs were purified from each fraction and subjected to qRT-PCR.…”

Section: Polysome Fractionationmentioning

confidence: 99%

HuR stabilizes a polyadenylated form of replication‐dependent histone mRNAs under stress conditions

et al. 2018

Self Cite

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All metazoan mRNAs have a poly(A) tail at the 3′ end with the exception of replication‐dependent histone (RDH) mRNAs, which end in a highly conserved stem‐loop (SL) structure. However, a subset of RDH mRNAs are reported to be polyadenylated under physiologic conditions. The molecular details of the biogenesis of polyadenylated RDH [poly(A)+ RDH] mRNAs remain unknown. In this study, our genome‐wide analyses reveal that puromycin treatment or UVC irradiation stabilizes poly(A)+ RDH mRNAs, relative to canonical RDH mRNAs, which end in an SL structure. We demonstrate that the stabilization of poly(A)+ RDH mRNAs occurs in a translation‐independent manner and is regulated via human antigen R (HuR) binding to the extended 3′ UTR under stress conditions. Our data suggest that HuR regulates the expression of poly(A)+ RDH mRNAs.—Ryu, I., Park, Y., Seo, J.‐W., Park, O. H., Ha, H., Nam, J.‐W., Kim, Y. K. HuR stabilizes a polyadenylated form of replication‐dependent histone mRNAs under stress conditions. FASEB J. 33, 2680–2693 (2019). http://www.fasebj.org

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Misfolded polypeptides are selectively recognized and transported toward aggresomes by a CED complex

Cited by 37 publications

References 67 publications

A first order phase transition mechanism underlies protein aggregation in mammalian cells

A first order phase transition mechanism underlies protein aggregation in mammalian cells

Mitochondrial carrier protein overloading and misfolding induce aggresomes and proteostatic adaptations in the cytosol

HuR stabilizes a polyadenylated form of replication‐dependent histone mRNAs under stress conditions

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