Ubiquitin-interacting motifs of ataxin-3 regulate its polyglutamine toxicity through Hsc70-4-dependent aggregation

Johnson, Sean L.; Ranxhi, Bedri; Libohova, Kozeta; Tsou, Wei‐Ling; Todi, Sokol V.

doi:10.7554/elife.60742

Cited by 21 publications

(54 citation statements)

References 92 publications

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“…Mutating the pathogenic ataxin-3 VBM improved fly motility and longevity compared to counterparts expressing pathogenic ataxin-3 Q80 with an intact VBM ( Ristic et al, 2018 ). Biochemically, mutating ataxin-3’s VBM or reducing the levels of VCP through RNA-interference did not reduce SCA3 protein levels, but decreased pathogenic ataxin-3 aggregation ( Johnson et al, 2020 ; Ristic et al, 2018 ) – a critical observation given that, in our assays with pathogenic ataxin-3, its aggregation precedes toxicity ( Johnson et al, 2019 ; Johnson et al, 2020 ; Ristic et al, 2018 ; Sutton et al, 2017 ). These and other findings led us to conclude that pathogenic ataxin-3 with a mutated VBM is less aggregation-prone and less toxic.…”

Section: Introductionmentioning

confidence: 73%

“…Human ataxin-3 cDNAs were based on sequences from previous publications and include either 77 or 80Q ( Berke et al, 2005 ; Blount et al, 2012 ; Harris et al, 2010 ; Johnson et al, 2019 ; Johnson et al, 2020 ; Nicastro et al, 2009 ; Nicastro et al, 2010 ; Ristic et al, 2018 ; Sutton et al, 2017 ; Todi et al, 2009 ; Tsou et al, 2015b ; Winborn et al, 2008 ). We used the company Genscript ( genscript.com ) to synthesize the VCP N-terminus cDNA as well as full-length fly VCP.…”

Section: Methodsmentioning

confidence: 99%

“…Transgenes were sub-cloned into pWalium-10.moe. Transgenic fly lines were generated via phiC31 integration into either attP2 (ataxin-3) on chromosome 3 or attP40 (N-VCP, VCP) on chromosome 2 ( Blount et al, 2012 ; Blount et al, 2020 ; Fish et al, 2007 ; Groth et al, 2004 ; Johnson et al, 2019 ; Johnson et al, 2020 ; Ristic et al, 2018 ; Sutton et al, 2017 ; Tsou et al, 2015b ; Tsou et al, 2016 ). Each insertion was confirmed and validated by PCR, genomic sequencing, and Western blotting, using procedures described in previous work ( Blount et al, 2018 ; Johnson et al, 2019 ; Johnson et al, 2020 ; Ristic et al, 2018 ; Sutton et al, 2017 ; Tsou et al, 2015b ; Tsou et al, 2016 ).…”

Section: Methodsmentioning

confidence: 99%

“…A body of work in polyQ diseases has highlighted a role for various non-polyQ regions and interactions in polyQ degeneration ( Johnson et al, 2020 ; Matos et al, 2011 ; Nath and Lieberman, 2017 ; Pandey and Rajamma, 2018 ; Paulson et al, 2017 ; Pérez Ortiz and Orr, 2018 ; Todi et al, 2007a ; Zoghbi and Orr, 2009 ). For ataxin-3, there are several domains that contribute to protein context and pathogenesis.…”

Section: Introductionmentioning

confidence: 99%

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Targeting the VCP-binding motif of ataxin-3 improves phenotypes in Drosophila models of Spinocerebellar Ataxia Type 3

Johnson

Libohova

Blount

et al. 2021

Neurobiology of Disease

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Of the family of polyglutamine (polyQ) neurodegenerative diseases, Spinocerebellar Ataxia Type 3 (SCA3) is the most common. Like other polyQ diseases, SCA3 stems from abnormal expansions in the CAG triplet repeat of its disease gene resulting in elongated polyQ repeats within its protein, ataxin-3. Various ataxin-3 protein domains contribute to its toxicity, including the valosin-containing protein (VCP)-binding motif (VBM). We previously reported that VCP, a homo-hexameric protein, enhances pathogenic ataxin-3 aggregation and exacerbates its toxicity. These findings led us to explore the impact of targeting the SCA3 protein by utilizing a decoy protein comprising the N-terminus of VCP (N-VCP) that binds ataxin-3’s VBM. The notion was that N-VCP would reduce binding of ataxin-3 to VCP, decreasing its aggregation and toxicity. We found that expression of N-VCP in Drosophila melanogaster models of SCA3 ameliorated various phenotypes, coincident with reduced ataxin-3 aggregation. This protective effect was specific to pathogenic ataxin-3 and depended on its VBM. Increasing the amount of N-VCP resulted in further phenotype improvement. Our work highlights the protective potential of targeting the VCP-ataxin-3 interaction in SCA3, a key finding in the search for therapeutic opportunities for this incurable disorder.

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Section: Introductionmentioning

confidence: 73%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Targeting the VCP-binding motif of ataxin-3 improves phenotypes in Drosophila models of Spinocerebellar Ataxia Type 3

Johnson

Libohova

Blount

et al. 2021

Neurobiology of Disease

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“…Furthermore, AT-3 UIMs are involved in multivalent binding to the Ubl domain of the E3 ubiquitin ligase parkin ( Bai et al, 2013 ; Aguirre et al, 2018 ). It has also been suggested that the three UIMs of AT-3 interact with the heat shock protein Hsc70-4 in Drosophila melanogaster ( Johnson et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Ubiquitin Interacting Motifs: Duality Between Structured and Disordered Motifs

Lambrughi

Maiani

Fas

et al. 2021

Front. Mol. Biosci.

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Ubiquitin is a small protein at the heart of many cellular processes, and several different protein domains are known to recognize and bind ubiquitin. A common motif for interaction with ubiquitin is the Ubiquitin Interacting Motif (UIM), characterized by a conserved sequence signature and often found in multi-domain proteins. Multi-domain proteins with intrinsically disordered regions mediate interactions with multiple partners, orchestrating diverse pathways. Short linear motifs for binding are often embedded in these disordered regions and play crucial roles in modulating protein function. In this work, we investigated the structural propensities of UIMs using molecular dynamics simulations and NMR chemical shifts. Despite the structural portrait depicted by X-crystallography of stable helical structures, we show that UIMs feature both helical and intrinsically disordered conformations. Our results shed light on a new class of disordered UIMs. This group is here exemplified by the C-terminal domain of one isoform of ataxin-3 and a group of ubiquitin-specific proteases. Intriguingly, UIMs not only bind ubiquitin. They can be a recruitment point for other interactors, such as parkin and the heat shock protein Hsc70-4. Disordered UIMs can provide versatility and new functions to the client proteins, opening new directions for research on their interactome.

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A phenotypically robust model of spinal and bulbar muscular atrophy in Drosophila

Richardson,

Sengupta,

Sujkowski

et al. 2023

J of Neuroscience Research

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Spinal and bulbar muscular atrophy (SBMA) is an X‐linked disorder that affects males who inherit the androgen receptor (AR) gene with an abnormal CAG triplet repeat expansion. The resulting protein contains an elongated polyglutamine (polyQ) tract and causes motor neuron degeneration in an androgen‐dependent manner. The precise molecular sequelae of SBMA are unclear. To assist with its investigation and the identification of therapeutic options, we report here a new model of SBMA in Drosophila melanogaster. We generated transgenic flies that express the full‐length, human AR with a wild‐type or pathogenic polyQ repeat. Each transgene is inserted into the same safe harbor site on the third chromosome of the fly as a single copy and in the same orientation. Expression of pathogenic AR, but not of its wild‐type variant, in neurons or muscles leads to consistent, progressive defects in longevity and motility that are concomitant with polyQ‐expanded AR protein aggregation and reduced complexity in neuromuscular junctions. Additional assays show adult fly eye abnormalities associated with the pathogenic AR species. The detrimental effects of pathogenic AR are accentuated by feeding flies the androgen, dihydrotestosterone. This new, robust SBMA model can be a valuable tool toward future investigations of this incurable disease.

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Ubiquitin-interacting motifs of ataxin-3 regulate its polyglutamine toxicity through Hsc70-4-dependent aggregation

Cited by 21 publications

References 92 publications

Targeting the VCP-binding motif of ataxin-3 improves phenotypes in Drosophila models of Spinocerebellar Ataxia Type 3

Targeting the VCP-binding motif of ataxin-3 improves phenotypes in Drosophila models of Spinocerebellar Ataxia Type 3

Ubiquitin Interacting Motifs: Duality Between Structured and Disordered Motifs

A phenotypically robust model of spinal and bulbar muscular atrophy in Drosophila

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