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Proteostasis of polyglutamine varies among neurons and predicts neurodegeneration


In polyglutamine (polyQ) diseases, only certain neurons die, despite widespread expression of the offending protein. PolyQ expansion may induce neurodegeneration by impairing proteostasis, but protein aggregation and toxicity tend to confound conventional measurements of protein stability. Here, we used optical pulse labeling to measure effects of polyQ expansions on the mean lifetime of a fragment of huntingtin, the protein that causes Huntington's disease, in living neurons. We show that polyQ expansion reduced the mean lifetime of mutant huntingtin within a given neuron and that the mean lifetime varied among neurons, indicating differences in their capacity to clear the polypeptide. We found that neuronal longevity is predicted by the mean lifetime of huntingtin, as cortical neurons cleared mutant huntingtin faster and lived longer than striatal neurons. Thus, cell type–specific differences in turnover capacity may contribute to cellular susceptibility to toxic proteins, and efforts to bolster proteostasis in Huntington's disease, such as protein clearance, could be neuroprotective.

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Figure 1: Optical pulse labeling to measure protein turnover in individual neurons.
Figure 2: PolyQ expansion destabilizes diffuse mHttex1 and full-length Htt.
Figure 3: Proteostasis of mhttex1 determines degeneration.
Figure 4: Nrf2, a stress-activated transcription factor, shortens the mean lifetime of mHttex1-Q46-Dendra2 and increases survival of striatal neurons.
Figure 5: Inhibiting the ubiquitin-proteasome system or autophagy differentially affects the mean lifetimes of Httex1-Q25-Dendra2 and mHttex1-Q46-Dendra2.
Figure 6: Neuron type–specific proteostasis of mHttex1 contributes to their susceptibility to degeneration.


  1. Han, I., You, Y., Kordower, J.H., Brady, S.T. & Morfini, G.A. Differential vulnerability of neurons in Huntington's disease: the role of cell type–specific features. J. Neurochem. 113, 1073–1091 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  2. Taylor, J.P., Hardy, J. & Fischbeck, K.H. Toxic proteins in neurodegenerative disease. Science 296, 1991–1995 (2002).

    Article  CAS  PubMed  Google Scholar 

  3. Kayed, R. et al. Common structure of soluble amyloid oligomers implies common mechanism of pathogenesis. Science 300, 486–489 (2003).

    Article  CAS  PubMed  Google Scholar 

  4. Miller, J. et al. Identifying polyglutamine protein species in situ that best predict neurodegeneration. Nat. Chem. Biol. 7, 925–934 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Gidalevitz, T., Ben-Zvi, A., Ho, K.H., Brignull, H.R. & Morimoto, R.I. Progressive disruption of cellular protein folding in models of polyglutamine diseases. Science 311, 1471–1474 (2006).

    Article  CAS  PubMed  Google Scholar 

  6. Mitra, S., Tsvetkov, A.S. & Finkbeiner, S. Single neuron ubiquitin-proteasome dynamics accompanying inclusion body formation in Huntington disease. J. Biol. Chem. 284, 4398–4403 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Tsvetkov, A.S. et al. A small-molecule scaffold induces autophagy in primary neurons and protects against toxicity in a Huntington disease model. Proc. Natl. Acad. Sci. USA 107, 16982–16987 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Takahashi, M. & Ono, Y. Pulse-chase analysis of protein kinase C. Methods Mol. Biol. 233, 163–170 (2003).

    CAS  PubMed  Google Scholar 

  9. Gurskaya, N.G. et al. Engineering of a monomeric green-to-red photoactivatable fluorescent protein induced by blue light. Nat. Biotechnol. 24, 461–465 (2006).

    Article  CAS  PubMed  Google Scholar 

  10. Arrasate, M. & Finkbeiner, S. Automated microscope system for determining factors that predict neuronal fate. Proc. Natl. Acad. Sci. USA 102, 3840–3845 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Leutenegger, A. et al. It's cheap to be colorful. Anthozoans show a slow turnover of GFP-like proteins. FEBS J. 274, 2496–2505 (2007).

    Article  CAS  PubMed  Google Scholar 

  12. Dantuma, N.P., Lindsten, K., Glas, R., Jellne, M. & Masucci, M.G. Short-lived green fluorescent proteins for quantifying ubiquitin/proteasome-dependent proteolysis in living cells. Nat. Biotechnol. 18, 538–543 (2000).

    Article  CAS  PubMed  Google Scholar 

  13. Zoghbi, H.Y. & Orr, H.T. Glutamine repeats and neurodegeneration. Annu. Rev. Neurosci. 23, 217–247 (2000).

    Article  CAS  PubMed  Google Scholar 

  14. DiFiglia, M. Clinical Genetics, II. Huntington's disease: from the gene to pathophysiology. Am. J. Psychiatry 154, 1046 (1997).

    Article  CAS  PubMed  Google Scholar 

  15. Sathasivam, K. et al. Aberrant splicing of HTT generates the pathogenic exon 1 protein in Huntington disease. Proc. Natl. Acad. Sci. USA 110, 2366–2370 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Wellington, C.L. & Hayden, M.R. Caspases and neurodegeneration: on the cutting edge of new therapeutic approaches. Clin. Genet. 57, 1–10 (2000).

    Article  CAS  PubMed  Google Scholar 

  17. Mangiarini, L. et al. Exon 1 of the HD gene with an expanded CAG repeat is sufficient to cause a progressive neurological phenotype in transgenic mice. Cell 87, 493–506 (1996).

    Article  CAS  PubMed  Google Scholar 

  18. Arrasate, M., Mitra, S., Schweitzer, E.S., Segal, M.R. & Finkbeiner, S. Inclusion body formation reduces levels of mutant huntingtin and the risk of neuronal death. Nature 431, 805–810 (2004).

    Article  CAS  PubMed  Google Scholar 

  19. Persichetti, F. et al. Differential expression of normal and mutant Huntington's disease gene alleles. Neurobiol. Dis. 3, 183–190 (1996).

    Article  CAS  PubMed  Google Scholar 

  20. Dyer, R.B. & McMurray, C.T. Mutant protein in Huntington disease is resistant to proteolysis in affected brain. Nat. Genet. 29, 270–278 (2001).

    Article  CAS  PubMed  Google Scholar 

  21. Kaytor, M.D., Wilkinson, K.D. & Warren, S.T. Modulating huntingtin half-life alters polyglutamine-dependent aggregate formation and cell toxicity. J. Neurochem. 89, 962–973 (2004).

    Article  CAS  PubMed  Google Scholar 

  22. Roscic, A., Baldo, B., Crochemore, C., Marcellin, D. & Paganetti, P. Induction of autophagy with catalytic mTOR inhibitors reduces huntingtin aggregates in a neuronal cell model. J. Neurochem. 119, 398–407 (2011).

    Article  CAS  PubMed  Google Scholar 

  23. Wu, J.C. et al. The regulation of N-terminal Huntingtin (Htt552) accumulation by Beclin1. Acta Pharmacol. Sin. 33, 743–751 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Kazantsev, A., Preisinger, E., Dranovsky, A., Goldgaber, D. & Housman, D. Insoluble detergent-resistant aggregates form between pathological and nonpathological lengths of polyglutamine in mammalian cells. Proc. Natl. Acad. Sci. USA 96, 11404–11409 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Kopito, R.R. Aggresomes, inclusion bodies and protein aggregation. Trends Cell Biol. 10, 524–530 (2000).

    CAS  PubMed  Google Scholar 

  26. Hartl, F.U. & Hayer-Hartl, M. Converging concepts of protein folding in vitro and in vivo. Nat. Struct. Mol. Biol. 16, 574–581 (2009).

    Article  CAS  PubMed  Google Scholar 

  27. Snell, R.G. et al. Relationship between trinucleotide repeat expansion and phenotypic variation in Huntington's disease. Nat. Genet. 4, 393–397 (1993).

    Article  CAS  PubMed  Google Scholar 

  28. Saudou, F., Finkbeiner, S., Devys, D. & Greenberg, M.E. Huntingtin acts in the nucleus to induce apoptosis but death does not correlate with the formation of intranuclear inclusions. Cell 95, 55–66 (1998).

    Article  CAS  PubMed  Google Scholar 

  29. Matsumoto, G., Kim, S. & Morimoto, R.I. Huntingtin and mutant SOD1 form aggregate structures with distinct molecular properties in human cells. J. Biol. Chem. 281, 4477–4485 (2006).

    Article  CAS  PubMed  Google Scholar 

  30. Lin, C.H. et al. Neurological abnormalities in a knock-in mouse model of Huntington's disease. Hum. Mol. Genet. 10, 137–144 (2001).

    Article  CAS  PubMed  Google Scholar 

  31. Colby, D.W., Cassady, J.P., Lin, G.C., Ingram, V.M. & Wittrup, K.D. Stochastic kinetics of intracellular huntingtin aggregate formation. Nat. Chem. Biol. 2, 319–323 (2006).

    Article  CAS  PubMed  Google Scholar 

  32. Slow, E.J. et al. Absence of behavioral abnormalities and neurodegeneration in vivo despite widespread neuronal huntingtin inclusions. Proc. Natl. Acad. Sci. USA 102, 11402–11407 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. Tsakiri, E.N. et al. Proteasome dysfunction in Drosophila signals to an Nrf2-dependent regulatory circuit aiming to restore proteostasis and prevent premature aging. Aging Cell (2013).

  34. Riley, B.E. et al. Ubiquitin accumulation in autophagy-deficient mice is dependent on the Nrf2-mediated stress response pathway: a potential role for protein aggregation in autophagic substrate selection. J. Cell Biol. 191, 537–552 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Zhang, Q.C. et al. A compact β model of huntingtin toxicity. J. Biol. Chem. 286, 8188–8196 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Bilimoria, P.M. & Bonni, A. Cultures of cerebellar granule neurons. Cold Spring Harb. Protoc. (2008).

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This work was supported by grants R01 3NS039746 and 2R01 NS045191 from the US National Institute of Neurological Disease and Stroke; grant P01 2AG022074 from the National Institute on Aging; by the Huntington's Disease Society of America (made possible with a gift from the James E. Bashaw Family); the Taube-Koret Center for Neurodegenerative disease and the Gladstone Institutes (S.F.); the Milton Wexler Award and a fellowship from the Hereditary Disease Foundation (A.S.T.); a fellowship from the Hillblom Foundation (M.A.); a fellowship from California Institute for Regenerative Medicine (P.S.), and in part by DMS-0914906 from the US National Science Foundation (B.A.S.). Gladstone Institutes received support from a US National Center for Research Resources Grant RR18928-01. We thank Y. Dabaghian, I. Kelmanson, A. Gelfand and members of the Finkbeiner laboratory for helpful discussions. The animal care facility was partly supported by a US National Institutes of Health Extramural Research Facilities Improvement Project (C06 RR018928). K. Nelson provided administrative assistance, and G.C. Howard, A.L. Lucido and S. Ordway edited the manuscript.

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Authors and Affiliations



A.S.T., M.A. and S.F. designed the study. A.S.T. and S.F. wrote the manuscript. B.A.S. performed statistical analysis and wrote the statistical analysis section of the manuscript. A.S.T., M.A., P.S., S.B. and D.M.A. wrote scripts for automated photoswitching and imaging. A.S.T. cloned all of the constructs used in the study. A.S.T. and M.A. cultured primary neurons and performed transfections, automated microscopy, fluorescence intensity measurements and data analysis. A.S.T. performed detergent extraction, metabolic labeling and photobleaching experiments. A.S.T. and P.S. performed survival analyses.

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Correspondence to Steven Finkbeiner.

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The authors declare no competing financial interests.

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Tsvetkov, A., Arrasate, M., Barmada, S. et al. Proteostasis of polyglutamine varies among neurons and predicts neurodegeneration. Nat Chem Biol 9, 586–592 (2013).

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