Ubiquitin-binding site 2 of ataxin-3 prevents its proteasomal degradation by interacting with Rad23

Blount, Jessica R.; Tsou, Wei‐Ling; Ristic, Gorica; Burr, Aaron A.; Ouyang, Michelle; Galante, Holland; Scaglione, K. Matthew; Todi, Sokol V.

doi:10.1038/ncomms5638

Cited by 59 publications

(86 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is possible that other lysine residues in Drosophila SIN3 are ubiquitinated, or that its proteasomal degradation might be ubiquitin-independent. There is a growing number of proteins that do not require ubiquitination to be degraded by the proteasome (24). Our initial studies, however, do not definitively rule out the possibility that ubiquitination of SIN3 220 is involved at some point to regulate its turnover.…”

Section: Discussionmentioning

confidence: 83%

Inter-isoform-dependent Regulation of the Drosophila Master Transcriptional Regulator SIN3

Chaubal

Todi

Pile

2016

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

SIN3 is a transcriptional corepressor that acts as a scaffold for a histone deacetylase (HDAC) complex. The SIN3 complex regulates various biological processes, including organ development, cell proliferation, and energy metabolism. Little is known, however, about the regulation of SIN3 itself. There are two major isoforms of Drosophila SIN3, 187 and 220, which are differentially expressed. Intrigued by the developmentally timed exchange of SIN3 isoforms, we examined whether SIN3 187 controls the fate of the 220 counterpart. Here, we show that in developing tissue, there is interplay between SIN3 isoforms: when SIN3 187 protein levels increase, SIN3 220 protein decreases concomitantly. SIN3 187 has a dual effect on SIN3 220. Expression of 187 leads to reduced 220 transcript, while also increasing the turnover of SIN3 220 protein by the proteasome. These data support the presence of a novel, inter-isoform-dependent mechanism that regulates the amount of SIN3 protein, and potentially the level of specific SIN3 complexes, during distinct developmental stages.Normal cell function requires precise and coordinated regulation of abundance, localization, and interaction of numerous proteins and associated factors. This systematic regulation is brought about by several synchronized processes that govern the production, subcellular location, and timely degradation of proteins. Key among these processes is the ubiquitin-proteasome system, which eliminates specific proteins at determined time points (1). Disturbance of the ubiquitin-proteasome system has serious consequences in cellular function that can directly cause cell death (2). This is especially true for controlling the steady-state levels of master regulatory proteins that regulate diverse transcriptional networks. Specific examples include the histone-modifying enzymes, which govern chromatin organization and thus regulate gene networks. Dysregulation of histone-modifying enzymes can be disastrous for the cell, because it not only leads to aberrant gene expression, but also affects genome stability (3).The SIN3 HDAC 2 complex, evolutionarily conserved from yeast to mammals, is one such important histone-modifying complex (4, 5). The protein SIN3 serves as a scaffold for the assembly of this complex (5). SIN3 is a master transcriptional regulator that, when deleted or mutated, causes embryonic lethality in Drosophila and mice (6 -9). Previous work from our laboratory showed that depletion of Drosophila SIN3 affects several biological processes, resulting in severe developmental defects, increased sensitivity to oxidative stress, and reduced life span (10 -12). Although many of the gene networks and biological processes regulated by SIN3 are known, the regulation of the SIN3 protein itself is poorly understood.In Drosophila, a single Sin3A gene gives rise to multiple SIN3 isoforms, SIN3 187, SIN3 190, and SIN3 220. These isoforms vary only at the C terminus due to the presence of unique C-terminal exons, form distinct HDAC complexes, are functionally non-redundant, ...

show abstract

Section: Discussionmentioning

confidence: 83%

Inter-isoform-dependent Regulation of the Drosophila Master Transcriptional Regulator SIN3

Chaubal

Todi

Pile

2016

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…SDS-PAGE, Western Blotting, and Quantification-Larvae, pupae, or flies, as indicated in figures and legends, were homogenized in boiling SDS lysis buffer (50 mM Tris, pH 6.8, 2% SDS, 10% glycerol, and 100 mM DTT), sonicated, boiled for 10 min, centrifuged for 10 min at 13,000 ϫ g at room temperature, loaded onto SDS-PAGE gels, electrophoresed at 160 -170 V, and transferred onto PVDF membranes (Bio-Rad) for Western blotting, as previously described (19,(22)(23)(24)(25). 10 larvae, 5 pupae, or 5 adults were collected per group in 15 l of lysis buffer per larva, 20 l of lysis buffer per pupa, or 30 l of buffer per adult.…”

Section: Methodsmentioning

confidence: 99%

“…Coomassie Blue staining was conducted as described before (26,27). Western blots were imaged with a charge-coupled device-equipped VersaDoc 5000MP system (Bio-Rad) (22,23). Quantification of signals from subsaturated blots was conducted with Quantity One Software (Bio-Rad) with universal background subtraction.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

USP5 Is Dispensable for Monoubiquitin Maintenance in Drosophila

Ristic

Tsou

Guzi

et al. 2016

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Ubiquitination is a post-translational modification that regulates most cellular pathways and processes, including degradation of proteins by the proteasome. Substrate ubiquitination is controlled at various stages, including through its reversal by deubiquitinases (DUBs). A critical outcome of this process is the recycling of monoubiquitin. One DUB whose function has been proposed to include monoubiquitin recycling is USP5. Here, we investigated whether Drosophila USP5 is important for maintaining monoubiquitin in vivo. We found that the fruit fly orthologue of USP5 has catalytic preferences similar to its human counterpart and that this DUB is necessary during fly development. Our biochemical and genetic experiments indicate that reduction of USP5 does not lead to monoubiquitin depletion in developing flies. Also, introduction of exogenous ubiquitin does not suppress developmental lethality caused by loss of endogenous USP5. Our work indicates that a primary physiological role of USP5 is not to recycle monoubiquitin for reutilization, but that it may involve disassembly of conjugated ubiquitin to maintain proteasome function.

show abstract

“…Detailed molecular domain studies identified the ubiquitin protease domain as critical: the Ataxin-3 protein with an expanded polyQ repeat retains this protective activity, suggesting that in disease, cleavage of Ataxin-3 to remove the protective ubiquitin protease domain would enhance pathogenesis (Warrick et al 2005). Further molecular analysis in mammalian cells identified the Ubiquitin Binding Site 2 (UbS2) of Ataxin-3 to negatively regulate the protein's turnover, via interaction with Rad23A and Rad23B (Blount et al 2014). Interestingly, decreasing the levels of Rad23 reduces SCA3 disease-associated toxicity.…”

Section: How Normal Protein Function and Protein Context Relates To Dmentioning

confidence: 99%

Drosophila as an In Vivo Model for Human Neurodegenerative Disease

2015

View full text Add to dashboard Cite

With the increase in the ageing population, neurodegenerative disease is devastating to families and poses a huge burden on society. The brain and spinal cord are extraordinarily complex: they consist of a highly organized network of neuronal and support cells that communicate in a highly specialized manner. One approach to tackling problems of such complexity is to address the scientific questions in simpler, yet analogous, systems. The fruit fly, Drosophila melanogaster, has been proven tremendously valuable as a model organism, enabling many major discoveries in neuroscientific disease research. The plethora of genetic tools available in Drosophila allows for exquisite targeted manipulation of the genome. Due to its relatively short lifespan, complex questions of brain function can be addressed more rapidly than in other model organisms, such as the mouse. Here we discuss features of the fly as a model for human neurodegenerative disease. There are many distinct fly models for a range of neurodegenerative diseases; we focus on select studies from models of polyglutamine disease and amyotrophic lateral sclerosis that illustrate the type and range of insights that can be gleaned. In discussion of these models, we underscore strengths of the fly in providing understanding into mechanisms and pathways, as a foundation for translational and therapeutic research.

show abstract

Ubiquitin-binding site 2 of ataxin-3 prevents its proteasomal degradation by interacting with Rad23

Cited by 59 publications

References 55 publications

Inter-isoform-dependent Regulation of the Drosophila Master Transcriptional Regulator SIN3

Inter-isoform-dependent Regulation of the Drosophila Master Transcriptional Regulator SIN3

USP5 Is Dispensable for Monoubiquitin Maintenance in Drosophila

Drosophila as an In Vivo Model for Human Neurodegenerative Disease

Contact Info

Product

Resources

About