Article | Published:

Huntingtin functions as a scaffold for selective macroautophagy

Nature Cell Biology volume 17, pages 262275 (2015) | Download Citation

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Abstract

Selective macroautophagy is an important protective mechanism against diverse cellular stresses. In contrast to the well-characterized starvation-induced autophagy, the regulation of selective autophagy is largely unknown. Here, we demonstrate that Huntingtin, the Huntington disease gene product, functions as a scaffold protein for selective macroautophagy but it is dispensable for non-selective macroautophagy. In Drosophila, Huntingtin genetically interacts with autophagy pathway components. In mammalian cells, Huntingtin physically interacts with the autophagy cargo receptor p62 to facilitate its association with the integral autophagosome component LC3 and with Lys-63-linked ubiquitin-modified substrates. Maximal activation of selective autophagy during stress is attained by the ability of Huntingtin to bind ULK1, a kinase that initiates autophagy, which releases ULK1 from negative regulation by mTOR. Our data uncover an important physiological function of Huntingtin and provide a missing link in the activation of selective macroautophagy in metazoans.

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Acknowledgements

We are grateful to T. Neufeld and U. Pandey for their fly lines; P. B. Dennis for the pRK5-GST-BHMT plasmid; D. Contamine for anti-Ref(2)P antibody; I. Bezprozvanny for MEF-Htt-WT and MEF-Htt-KO lines; M. Kundu for MEF-ULK1-KO and MEF-ULK1-WT lines; J. Botas for UAS–hHtt DNA and fly lines. We also thank Z. Mao for technical assistance in confocal microscopy, and Z. Sun and N. Perrimon for critically reading the manuscript. H.J.B. is an investigator of the HHMI and supported by the R&R Belfer and Hufftington foundations. G.D. was supported by a T32 developmental biology training grant from the NICHD. This work was supported by NIH grants R01-NS069880 (to S.Z.) and P01-AG031782 and AG038072 (to A.M.C.) and the generous support of R&R Belfer (to A.M.C.).

Author information

Author notes

    • Yan-Ning Rui
    • , Zhen Xu
    •  & Bindi Patel

    These authors contributed equally to this work.

Affiliations

  1. The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston (UTHealth), 1825 Pressler Street Houston, Texas 77030, USA

    • Yan-Ning Rui
    • , Zhen Xu
    • , Zhihua Chen
    • , Dongsheng Chen
    • , Antonio Tito
    • , Yamin Sun
    •  & Sheng Zhang
  2. Department of Development and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA

    • Bindi Patel
    •  & Ana Maria Cuervo
  3. Programs in Human and Molecular Genetics and Neuroscience, The University of Texas Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston (UTHealth), 1825 Pressler Street Houston, Texas 77030, USA

    • Antonio Tito
    •  & Sheng Zhang
  4. Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, 1250 Moursund Street Houston, Texas 77030, USA

    • Gabriela David
    •  & Hugo J. Bellen
  5. Department of Neurology, The University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston (UTHealth), 6341 Fannin Street Houston, Texas 77030, USA

    • Erin F. Stimming
  6. Howard Hughes Medical Institute, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, 1250 Moursund Street Houston, Texas 77030, USA

    • Hugo J. Bellen
  7. Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, 1250 Moursund Street Houston, Texas 77030, USA

    • Hugo J. Bellen
  8. Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA

    • Ana Maria Cuervo
  9. Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, New York 10461, USA

    • Ana Maria Cuervo
  10. Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, The University of Texas Health Science Center at Houston (UTHealth), 1825 Pressler Street Houston, Texas 77030, USA

    • Sheng Zhang

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Contributions

Y-N.R. and Z.X. designed and performed most Drosophila studies and most of the studies on starvation- and MG132-induced autophagy response and Tau-ΔC degradation in mammalian cells; B.P. designed and performed part of the studies on autophagic flux in mammalian cells, and most of the studies of lipophagy and mitophagy, some of the co-immunoprecipitation studies and all the electron microscopy studies and morphometric analysis; Z.C., D.C., A.T., E.F.S. and Y.S. contributed to part of these studies; G.D. performed larva starvation, LysoTracker staining and LC3 reporter assay; G.D. and H.J.B. designed experiments, analysed data and contributed to part of the writing and revision of the manuscript; A.M.C. coordinated the study, designed experiments, analysed data and contributed to the writing and revision of the manuscript. S.Z. coordinated the study, designed experiments, analysed data and contributed to the main writing and revision of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Ana Maria Cuervo or Sheng Zhang.

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https://doi.org/10.1038/ncb3101

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