1
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Yap ZY, Park YH, Wortmann SB, Gunning AC, Ezer S, Lee S, Duraine L, Wilichowski E, Wilson K, Mayr JA, Wagner M, Li H, Kini U, Black ED, Monaghan KG, Lupski JR, Ellard S, Westphal DS, Harel T, Yoon WH. Functional interpretation of ATAD3A variants in neuro-mitochondrial phenotypes. Genome Med 2021; 13:55. [PMID: 33845882 PMCID: PMC8042885 DOI: 10.1186/s13073-021-00873-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 03/17/2021] [Indexed: 12/20/2022] Open
Abstract
Background ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane-anchored protein involved in diverse processes including mitochondrial dynamics, mitochondrial DNA organization, and cholesterol metabolism. Biallelic deletions (null), recessive missense variants (hypomorph), and heterozygous missense variants or duplications (antimorph) in ATAD3A lead to neurological syndromes in humans. Methods To expand the mutational spectrum of ATAD3A variants and to provide functional interpretation of missense alleles in trans to deletion alleles, we performed exome sequencing for identification of single nucleotide variants (SNVs) and copy number variants (CNVs) in ATAD3A in individuals with neurological and mitochondrial phenotypes. A Drosophila Atad3a Gal4 knockin-null allele was generated using CRISPR-Cas9 genome editing technology to aid the interpretation of variants. Results We report 13 individuals from 8 unrelated families with biallelic ATAD3A variants. The variants included four missense variants inherited in trans to loss-of-function alleles (p.(Leu77Val), p.(Phe50Leu), p.(Arg170Trp), p.(Gly236Val)), a homozygous missense variant p.(Arg327Pro), and a heterozygous non-frameshift indel p.(Lys568del). Affected individuals exhibited findings previously associated with ATAD3A pathogenic variation, including developmental delay, hypotonia, congenital cataracts, hypertrophic cardiomyopathy, and cerebellar atrophy. Drosophila studies indicated that Phe50Leu, Gly236Val, Arg327Pro, and Lys568del are severe loss-of-function alleles leading to early developmental lethality. Further, we showed that Phe50Leu, Gly236Val, and Arg327Pro cause neurogenesis defects. On the contrary, Leu77Val and Arg170Trp are partial loss-of-function alleles that cause progressive locomotion defects and whose expression leads to an increase in autophagy and mitophagy in adult muscles. Conclusion Our findings expand the allelic spectrum of ATAD3A variants and exemplify the use of a functional assay in Drosophila to aid variant interpretation.
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Affiliation(s)
- Zheng Yie Yap
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Yo Han Park
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Saskia B Wortmann
- Institute of Human Genetics, Technical University Munich, Munich, Germany.,University Children's Hospital, Paracelsus Medical University (PMU), Salzburg, Austria.,Radboud Centre for Mitochondrial Medicine (RCMM), Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Adam C Gunning
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, EX2 5DW, UK.,Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, EX2 5DW, UK
| | - Shlomit Ezer
- Department of Genetics, Hadassah Medical Center, POB 12000, 9112001, Jerusalem, Israel.,Faculty of Medicine, Hebrew University of Jerusalem, POB 12000, 9112001, Jerusalem, Israel
| | - Sukyeong Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Lita Duraine
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Ekkehard Wilichowski
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Kate Wilson
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Johannes A Mayr
- University Children's Hospital, Paracelsus Medical University (PMU), Salzburg, Austria
| | - Matias Wagner
- Institute of Human Genetics, Technical University Munich, Munich, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Hong Li
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, USA.,Department of Pediatrics, School of Medicine, Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - Usha Kini
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Emily Davis Black
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, USA
| | | | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Texas Children's Hospital, Houston, TX, USA
| | - Sian Ellard
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, EX2 5DW, UK.,Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, EX2 5DW, UK
| | - Dominik S Westphal
- Institute of Human Genetics, Technical University Munich, Munich, Germany
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, POB 12000, 9112001, Jerusalem, Israel. .,Faculty of Medicine, Hebrew University of Jerusalem, POB 12000, 9112001, Jerusalem, Israel.
| | - Wan Hee Yoon
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA.
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2
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Han SY, Pandey A, Moore T, Galeone A, Duraine L, Cowan TM, Jafar-Nejad H. A conserved role for AMP-activated protein kinase in NGLY1 deficiency. PLoS Genet 2020; 16:e1009258. [PMID: 33315951 PMCID: PMC7769621 DOI: 10.1371/journal.pgen.1009258] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 12/28/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
Mutations in human N-glycanase 1 (NGLY1) cause the first known congenital disorder of deglycosylation (CDDG). Patients with this rare disease, which is also known as NGLY1 deficiency, exhibit global developmental delay and other phenotypes including neuropathy, movement disorder, and constipation. NGLY1 is known to regulate proteasomal and mitophagy gene expression through activation of a transcription factor called "nuclear factor erythroid 2-like 1" (NFE2L1). Loss of NGLY1 has also been shown to impair energy metabolism, but the molecular basis for this phenotype and its in vivo consequences are not well understood. Using a combination of genetic studies, imaging, and biochemical assays, here we report that loss of NGLY1 in the visceral muscle of the Drosophila larval intestine results in a severe reduction in the level of AMP-activated protein kinase α (AMPKα), leading to energy metabolism defects, impaired gut peristalsis, failure to empty the gut, and animal lethality. Ngly1-/- mouse embryonic fibroblasts and NGLY1 deficiency patient fibroblasts also show reduced AMPKα levels. Moreover, pharmacological activation of AMPK signaling significantly suppressed the energy metabolism defects in these cells. Importantly, the reduced AMPKα level and impaired energy metabolism observed in NGLY1 deficiency models are not caused by the loss of NFE2L1 activity. Taken together, these observations identify reduced AMPK signaling as a conserved mediator of energy metabolism defects in NGLY1 deficiency and suggest AMPK signaling as a therapeutic target in this disease.
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Affiliation(s)
- Seung Yeop Han
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ashutosh Pandey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Tereza Moore
- Department of Pathology, Stanford University, Stanford, California, United States of America
| | - Antonio Galeone
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Jan & Dan Duncan Neurological Research Institute Center, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Tina M. Cowan
- Department of Pathology, Stanford University, Stanford, California, United States of America
| | - Hamed Jafar-Nejad
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Genetics & Genomics Graduate Program, Baylor College of Medicine, Houston, Texas, United States of America
- Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
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3
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Ojelade SA, Lee TV, Giagtzoglou N, Yu L, Ugur B, Li Y, Duraine L, Zuo Z, Petyuk V, De Jager PL, Bennett DA, Arenkiel BR, Bellen HJ, Shulman JM. cindr, the Drosophila Homolog of the CD2AP Alzheimer's Disease Risk Gene, Is Required for Synaptic Transmission and Proteostasis. Cell Rep 2020; 28:1799-1813.e5. [PMID: 31412248 PMCID: PMC6703184 DOI: 10.1016/j.celrep.2019.07.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 05/30/2019] [Accepted: 07/15/2019] [Indexed: 12/11/2022] Open
Abstract
The Alzheimer’s disease (AD) susceptibility gene, CD2-associated protein (CD2AP), encodes an actin binding adaptor protein, but its function in the nervous system is largely unknown. Loss of the Drosophila ortholog cindr enhances neurotoxicity of human Tau, which forms neurofibrillary tangle pathology in AD. We show that Cindr is expressed in neurons and present at synaptic terminals. cindr mutants show impairments in synapse maturation and both synaptic vesicle recycling and release. Cindr associates and genetically interacts with 14-3-3ζ, regulates the ubiquitin-proteasome system, and affects turnover of Synapsin and the plasma membrane calcium ATPase (PMCA). Loss of cindr elevates PMCA levels and reduces cytosolic calcium. Studies of Cd2ap null mice support a conserved role in synaptic proteostasis, and CD2AP protein levels are inversely related to Synapsin abundance in human postmortem brains. Our results reveal CD2AP neuronal requirements with relevance to AD susceptibility, including for proteostasis, calcium handling, and synaptic structure and function. CD2AP is an Alzheimer’s disease susceptibility gene with uncertain brain function. Ojelade et al. discover that mutation of the Drosophila homolog cindr disrupts ubiquitin-proteasome system activity, causing calcium dyshomeostasis and impaired synaptic vesicle recycling and release. Cd2ap null mice and human brain proteomic studies support a conserved role in synaptic proteostasis.
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Affiliation(s)
- Shamsideen A Ojelade
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Tom V Lee
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Nikolaos Giagtzoglou
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Berrak Ugur
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yarong Li
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vlad Petyuk
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology and the Taub Institute, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Benjamin R Arenkiel
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joshua M Shulman
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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4
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Kao CY, Xu M, Wang L, Lin SC, Lee HJ, Duraine L, Bellen HJ, Goldstein DS, Tsai SY, Tsai MJ. Elevated COUP-TFII expression in dopaminergic neurons accelerates the progression of Parkinson's disease through mitochondrial dysfunction. PLoS Genet 2020; 16:e1008868. [PMID: 32579581 PMCID: PMC7340320 DOI: 10.1371/journal.pgen.1008868] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 07/07/2020] [Accepted: 05/18/2020] [Indexed: 11/19/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder featuring progressive loss of midbrain dopaminergic (DA) neurons that leads to motor symptoms. The etiology and pathogenesis of PD are not clear. We found that expression of COUP-TFII, an orphan nuclear receptor, in DA neurons is upregulated in PD patients through the analysis of public datasets. We show here that through epigenetic regulation, COUP-TFII contributes to oxidative stress, suggesting that COUP-TFII may play a role in PD pathogenesis. Elevated COUP-TFII expression specifically in DA neurons evokes DA neuronal loss in mice and accelerates the progression of phenotypes in a PD mouse model, MitoPark. Compared to control mice, those with elevated COUP-TFII expression displayed reduced cristae in mitochondria and enhanced cellular electron-dense vacuoles in the substantia nigra pars compacta. Mechanistically, we found that overexpression of COUP-TFII disturbs mitochondrial pathways, resulting in mitochondrial dysfunction. In particular, there is repressed expression of genes encoding cytosolic aldehyde dehydrogenases, which could enhance oxidative stress and interfere with mitochondrial function via 3,4-dihydroxyphenylacetaldehyde (DOPAL) buildup in DA neurons. Importantly, under-expression of COUP-TFII in DA neurons slowed the deterioration in motor functions of MitoPark mice. Taken together, our results suggest that COUP-TFII may be an important contributor to PD development and a potential therapeutic target.
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Affiliation(s)
- Chung-Yang Kao
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mafei Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Leiming Wang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shih-Chieh Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hui-Ju Lee
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lita Duraine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - David S. Goldstein
- Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sophia Y. Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ming-Jer Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
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5
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Chung HL, Wangler MF, Marcogliese PC, Jo J, Ravenscroft TA, Zuo Z, Duraine L, Sadeghzadeh S, Li-Kroeger D, Schmidt RE, Pestronk A, Rosenfeld JA, Burrage L, Herndon MJ, Chen S, Shillington A, Vawter-Lee M, Hopkin R, Rodriguez-Smith J, Henrickson M, Lee B, Moser AB, Jones RO, Watkins P, Yoo T, Mar S, Choi M, Bucelli RC, Yamamoto S, Lee HK, Prada CE, Chae JH, Vogel TP, Bellen HJ. Loss- or Gain-of-Function Mutations in ACOX1 Cause Axonal Loss via Different Mechanisms. Neuron 2020; 106:589-606.e6. [PMID: 32169171 PMCID: PMC7289150 DOI: 10.1016/j.neuron.2020.02.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 01/03/2020] [Accepted: 02/13/2020] [Indexed: 12/01/2022]
Abstract
ACOX1 (acyl-CoA oxidase 1) encodes the first and rate-limiting enzyme of the very-long-chain fatty acid (VLCFA) β-oxidation pathway in peroxisomes and leads to H2O2 production. Unexpectedly, Drosophila (d) ACOX1 is mostly expressed and required in glia, and loss of ACOX1 leads to developmental delay, pupal death, reduced lifespan, impaired synaptic transmission, and glial and axonal loss. Patients who carry a previously unidentified, de novo, dominant variant in ACOX1 (p.N237S) also exhibit glial loss. However, this mutation causes increased levels of ACOX1 protein and function resulting in elevated levels of reactive oxygen species in glia in flies and murine Schwann cells. ACOX1 (p.N237S) patients exhibit a severe loss of Schwann cells and neurons. However, treatment of flies and primary Schwann cells with an antioxidant suppressed the p.N237S-induced neurodegeneration. In summary, both loss and gain of ACOX1 lead to glial and neuronal loss, but different mechanisms are at play and require different treatments.
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Affiliation(s)
- Hyung-Lok Chung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Paul C Marcogliese
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Juyeon Jo
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Thomas A Ravenscroft
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sina Sadeghzadeh
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | - David Li-Kroeger
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Robert E Schmidt
- Department of Pathology and Immunology, Division of Neuropathology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alan Pestronk
- Department of Pathology and Immunology, Division of Neuropathology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mitchell J Herndon
- Department of Pathology and Immunology, Division of Neuropathology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shan Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Amelle Shillington
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Marissa Vawter-Lee
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Robert Hopkin
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Jackeline Rodriguez-Smith
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Division of Rheumatology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Michael Henrickson
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Division of Rheumatology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ann B Moser
- Division of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Richard O Jones
- Division of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Paul Watkins
- Division of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Taekyeong Yoo
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soe Mar
- Department of Neurology, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Murim Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Robert C Bucelli
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hyun Kyoung Lee
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Carlos E Prada
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Jong-Hee Chae
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Tiphanie P Vogel
- Department of Pediatrics, Section of Rheumatology, Baylor College of Medicine, Center for Human Immunobiology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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6
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Wang J, Rousseau J, Kim E, Ehresmann S, Cheng YT, Duraine L, Zuo Z, Park YJ, Li-Kroeger D, Bi W, Wong LJ, Rosenfeld J, Gleeson J, Faqeih E, Alkuraya FS, Wierenga KJ, Chen J, Afenjar A, Nava C, Doummar D, Keren B, Juusola J, Grompe M, Bellen HJ, Campeau PM. Loss of Oxidation Resistance 1, OXR1, Is Associated with an Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction. Am J Hum Genet 2019; 105:1237-1253. [PMID: 31785787 PMCID: PMC6904826 DOI: 10.1016/j.ajhg.2019.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 11/01/2019] [Indexed: 12/28/2022] Open
Abstract
We report an early-onset autosomal-recessive neurological disease with cerebellar atrophy and lysosomal dysfunction. We identified bi-allelic loss-of-function (LoF) variants in Oxidative Resistance 1 (OXR1) in five individuals from three families; these individuals presented with a history of severe global developmental delay, current intellectual disability, language delay, cerebellar atrophy, and seizures. While OXR1 is known to play a role in oxidative stress resistance, its molecular functions are not well established. OXR1 contains three conserved domains: LysM, GRAM, and TLDc. The gene encodes at least six transcripts, including some that only consist of the C-terminal TLDc domain. We utilized Drosophila to assess the phenotypes associated with loss of mustard (mtd), the fly homolog of OXR1. Strong LoF mutants exhibit late pupal lethality or pupal eclosion defects. Interestingly, although mtd encodes 26 transcripts, severe LoF and null mutations can be rescued by a single short human OXR1 cDNA that only contains the TLDc domain. Similar rescue is observed with the TLDc domain of NCOA7, another human homolog of mtd. Loss of mtd in neurons leads to massive cell loss, early death, and an accumulation of aberrant lysosomal structures, similar to what we observe in fibroblasts of affected individuals. Our data indicate that mtd and OXR1 are required for proper lysosomal function; this is consistent with observations that NCOA7 is required for lysosomal acidification.
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Affiliation(s)
- Julia Wang
- Program in Developmental Biology, Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Justine Rousseau
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada
| | - Emily Kim
- Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Sophie Ehresmann
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada
| | - Yi-Ting Cheng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ye-Jin Park
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Li-Kroeger
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joseph Gleeson
- Rady Institute of Genomic Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Eissa Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, 11525, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, 11525, Saudi Arabia
| | - Klaas J Wierenga
- Department of Pediatrics, Oklahoma University Health Sciences Center (OUHSC), Oklahoma City, OK 26901, USA; Department of Clinical Genomics, Mayo Clinic Florida, Jacksonville, FL 32224, USA
| | - Jiani Chen
- Department of Pediatrics, Oklahoma University Health Sciences Center (OUHSC), Oklahoma City, OK 26901, USA; Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alexandra Afenjar
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France; Département de Génétique et Embryologie Médicale, CRMR des Malformations et Maladies Congénitales du Cervelet, GRC ConCer-LD, Sorbonne Universités, Hôpital Trousseau, Paris, 75012 France
| | - Caroline Nava
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France
| | - Diane Doummar
- Assistance Publique des Hôpitaux de Paris, Service de Neuropédiatrie, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012 France
| | - Boris Keren
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France
| | | | - Markus Grompe
- Department of Pediatrics, Oregon Health and Science University, Portland, Oregon 97201, USA; Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97201, USA
| | - Hugo J Bellen
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute and Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Philippe M Campeau
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada.
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7
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Scavuzzo MA, Chmielowiec J, Yang D, Wamble K, Chaboub LS, Duraine L, Tepe B, Glasgow SM, Arenkiel BR, Brou C, Deneen B, Borowiak M. Pancreatic Cell Fate Determination Relies on Notch Ligand Trafficking by NFIA. Cell Rep 2018; 25:3811-3827.e7. [PMID: 30590051 DOI: 10.1016/j.celrep.2018.11.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/28/2018] [Accepted: 11/20/2018] [Indexed: 12/24/2022] Open
Abstract
Notch is activated globally in pancreatic progenitors; however, for progenitors to differentiate into endocrine cells, they must escape Notch activation to express Neurogenin-3. Here, we find that the transcription factor nuclear factor I/A (NFIA) promotes endocrine development by regulating Notch ligand Dll1 trafficking. Pancreatic deletion of NFIA leads to cell fate defects, with increased duct and decreased endocrine formation, while ectopic expression promotes endocrine formation in mice and human pancreatic progenitors. NFIA-deficient mice exhibit dysregulation of trafficking-related genes including increased expression of Mib1, which acts to target Dll1 for endocytosis. We find that NFIA binds to the Mib1 promoter, with loss of NFIA leading to an increase in Dll1 internalization and enhanced Notch activation with rescue of the cell fate defects after Mib1 knockdown. This study reveals NFIA as a pro-endocrine factor in the pancreas, acting to repress Mib1, inhibit Dll1 endocytosis and thus promote escape from Notch activation.
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Affiliation(s)
- Marissa A Scavuzzo
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jolanta Chmielowiec
- Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, TX 77030, USA; Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Diane Yang
- Molecular and Cellular Biology Department, Baylor College of Medicine, Houston, TX 77030, USA
| | - Katrina Wamble
- Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, TX 77030, USA; Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lesley S Chaboub
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Burak Tepe
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stacey M Glasgow
- Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, TX 77030, USA; Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Benjamin R Arenkiel
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; McNair Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christel Brou
- Department of Cell Biology and Infection, Institute Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Benjamin Deneen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, TX 77030, USA; Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Malgorzata Borowiak
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, and Houston Methodist Hospital, Houston, TX 77030, USA; Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA; Molecular and Cellular Biology Department, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; McNair Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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8
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Tan KL, Haelterman NA, Kwartler CS, Regalado ES, Lee PT, Nagarkar-Jaiswal S, Guo DC, Duraine L, Wangler MF, Bamshad MJ, Nickerson DA, Lin G, Milewicz DM, Bellen HJ. Ari-1 Regulates Myonuclear Organization Together with Parkin and Is Associated with Aortic Aneurysms. Dev Cell 2018; 45:226-244.e8. [PMID: 29689197 PMCID: PMC5920516 DOI: 10.1016/j.devcel.2018.03.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/15/2018] [Accepted: 03/26/2018] [Indexed: 12/25/2022]
Abstract
Nuclei are actively positioned and anchored to the cytoskeleton via the LINC (Linker of Nucleoskeleton and Cytoskeleton) complex. We identified mutations in the Parkin-like E3 ubiquitin ligase Ariadne-1 (Ari-1) that affect the localization and distribution of LINC complex members in Drosophila. ari-1 mutants exhibit nuclear clustering and morphology defects in larval muscles. We show that Ari-1 mono-ubiquitinates the core LINC complex member Koi. Surprisingly, we discovered functional redundancy between Parkin and Ari-1: increasing Parkin expression rescues ari-1 mutant phenotypes and vice versa. We further show that rare variants in the human homolog of ari-1 (ARIH1) are associated with thoracic aortic aneurysms and dissections, conditions resulting from smooth muscle cell (SMC) dysfunction. Human ARIH1 rescues fly ari-1 mutant phenotypes, whereas human variants found in patients fail to do so. In addition, SMCs obtained from patients display aberrant nuclear morphology. Hence, ARIH1 is critical in anchoring myonuclei to the cytoskeleton.
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Affiliation(s)
- Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Callie S Kwartler
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Ellen S Regalado
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Sonal Nagarkar-Jaiswal
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA
| | - Dong-Chuan Guo
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Lita Duraine
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA
| | - Michael F Wangler
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Michael J Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Dianna M Milewicz
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital (TCH), Houston, TX 77030, USA; Department of Neuroscience, BCM, Houston, TX 77030, USA.
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9
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Harel T, Yoon WH, Garone C, Gu S, Coban-Akdemir Z, Eldomery MK, Posey JE, Jhangiani SN, Rosenfeld JA, Cho MT, Fox S, Withers M, Brooks SM, Chiang T, Duraine L, Erdin S, Yuan B, Shao Y, Moussallem E, Lamperti C, Donati MA, Smith JD, McLaughlin HM, Eng CM, Walkiewicz M, Xia F, Pippucci T, Magini P, Seri M, Zeviani M, Hirano M, Hunter JV, Srour M, Zanigni S, Lewis RA, Muzny DM, Lotze TE, Boerwinkle E, Gibbs RA, Hickey SE, Graham BH, Yang Y, Buhas D, Martin DM, Potocki L, Graziano C, Bellen HJ, Lupski JR, Bellen HJ, Lupski JR. Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes. Am J Hum Genet 2016; 99:831-845. [PMID: 27640307 DOI: 10.1016/j.ajhg.2016.08.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/04/2016] [Indexed: 12/22/2022] Open
Abstract
ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.Arg528Trp) variant by whole-exome sequencing (WES) in five unrelated individuals with a core phenotype of global developmental delay, hypotonia, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. We also describe two families with biallelic variants in ATAD3A, including a homozygous variant in two siblings, and biallelic ATAD3A deletions mediated by nonallelic homologous recombination (NAHR) between ATAD3A and gene family members ATAD3B and ATAD3C. Tissue-specific overexpression of borR534W, the Drosophila mutation homologous to the human c.1582C>T (p.Arg528Trp) variant, resulted in a dramatic decrease in mitochondrial content, aberrant mitochondrial morphology, and increased autophagy. Homozygous null bor larvae showed a significant decrease of mitochondria, while overexpression of borWT resulted in larger, elongated mitochondria. Finally, fibroblasts of an affected individual exhibited increased mitophagy. We conclude that the p.Arg528Trp variant functions through a dominant-negative mechanism that results in small mitochondria that trigger mitophagy, resulting in a reduction in mitochondrial content. ATAD3A variation represents an additional link between mitochondrial dynamics and recognizable neurological syndromes, as seen with MFN2, OPA1, DNM1L, and STAT2 mutations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
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10
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Chen K, Lin G, Haelterman NA, Ho TSY, Li T, Li Z, Duraine L, Graham BH, Jaiswal M, Yamamoto S, Rasband MN, Bellen HJ. Loss of Frataxin induces iron toxicity, sphingolipid synthesis, and Pdk1/Mef2 activation, leading to neurodegeneration. eLife 2016; 5:e16043. [PMID: 27343351 PMCID: PMC4956409 DOI: 10.7554/elife.16043] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Mutations in Frataxin (FXN) cause Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder. Previous studies have proposed that loss of FXN causes mitochondrial dysfunction, which triggers elevated reactive oxygen species (ROS) and leads to the demise of neurons. Here we describe a ROS independent mechanism that contributes to neurodegeneration in fly FXN mutants. We show that loss of frataxin homolog (fh) in Drosophila leads to iron toxicity, which in turn induces sphingolipid synthesis and ectopically activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2). Dampening iron toxicity, inhibiting sphingolipid synthesis by Myriocin, or reducing Pdk1 or Mef2 levels, all effectively suppress neurodegeneration in fh mutants. Moreover, increasing dihydrosphingosine activates Mef2 activity through PDK1 in mammalian neuronal cell line suggesting that the mechanisms are evolutionarily conserved. Our results indicate that an iron/sphingolipid/Pdk1/Mef2 pathway may play a role in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
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11
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David-Morrison G, Xu Z, Rui YN, Charng WL, Jaiswal M, Yamamoto S, Xiong B, Zhang K, Sandoval H, Duraine L, Zuo Z, Zhang S, Bellen HJ. WAC Regulates mTOR Activity by Acting as an Adaptor for the TTT and Pontin/Reptin Complexes. Dev Cell 2016; 36:139-51. [PMID: 26812014 DOI: 10.1016/j.devcel.2015.12.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/16/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
Abstract
The ability to sense energy status is crucial in the regulation of metabolism via the mechanistic Target of Rapamycin Complex 1 (mTORC1). The assembly of the TTT-Pontin/Reptin complex is responsive to changes in energy status. Under energy-sufficient conditions, the TTT-Pontin/Reptin complex promotes mTORC1 dimerization and mTORC1-Rag interaction, which are critical for mTORC1 activation. We show that WAC is a regulator of energy-mediated mTORC1 activity. In a Drosophila screen designed to isolate mutations that cause neuronal dysfunction, we identified wacky, the homolog of WAC. Loss of Wacky leads to neurodegeneration, defective mTOR activity, and increased autophagy. Wacky and WAC have conserved physical interactions with mTOR and its regulators, including Pontin and Reptin, which bind to the TTT complex to regulate energy-dependent activation of mTORC1. WAC promotes the interaction between TTT and Pontin/Reptin in an energy-dependent manner, thereby promoting mTORC1 activity by facilitating mTORC1 dimerization and mTORC1-Rag interaction.
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Affiliation(s)
| | - Zhen Xu
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Yan-Ning Rui
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sheng Zhang
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Programs in Human and Molecular Genetics and Neuroscience, The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA.
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.
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12
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Wang S, Tan KL, Agosto MA, Xiong B, Yamamoto S, Sandoval H, Jaiswal M, Bayat V, Zhang K, Charng WL, David G, Duraine L, Venkatachalam K, Wensel TG, Bellen HJ. Correction: The Retromer Complex Is Required for Rhodopsin Recycling and Its Loss Leads to Photoreceptor Degeneration. PLoS Biol 2015; 13:e1002170. [PMID: 26020534 PMCID: PMC4447419 DOI: 10.1371/journal.pbio.1002170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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13
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Tian X, Gala U, Zhang Y, Shang W, Nagarkar Jaiswal S, di Ronza A, Jaiswal M, Yamamoto S, Sandoval H, Duraine L, Sardiello M, Sillitoe RV, Venkatachalam K, Fan H, Bellen HJ, Tong C. A voltage-gated calcium channel regulates lysosomal fusion with endosomes and autophagosomes and is required for neuronal homeostasis. PLoS Biol 2015; 13:e1002103. [PMID: 25811491 PMCID: PMC4374850 DOI: 10.1371/journal.pbio.1002103] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 02/11/2015] [Indexed: 01/03/2023] Open
Abstract
Autophagy helps deliver sequestered intracellular cargo to lysosomes for proteolytic degradation and thereby maintains cellular homeostasis by preventing accumulation of toxic substances in cells. In a forward mosaic screen in Drosophila designed to identify genes required for neuronal function and maintenance, we identified multiple cacophony (cac) mutant alleles. They exhibit an age-dependent accumulation of autophagic vacuoles (AVs) in photoreceptor terminals and eventually a degeneration of the terminals and surrounding glia. cac encodes an α1 subunit of a Drosophila voltage-gated calcium channel (VGCC) that is required for synaptic vesicle fusion with the plasma membrane and neurotransmitter release. Here, we show that cac mutant photoreceptor terminals accumulate AV-lysosomal fusion intermediates, suggesting that Cac is necessary for the fusion of AVs with lysosomes, a poorly defined process. Loss of another subunit of the VGCC, α2δ or straightjacket (stj), causes phenotypes very similar to those caused by the loss of cac, indicating that the VGCC is required for AV-lysosomal fusion. The role of VGCC in AV-lysosomal fusion is evolutionarily conserved, as the loss of the mouse homologues, Cacna1a and Cacna2d2, also leads to autophagic defects in mice. Moreover, we find that CACNA1A is localized to the lysosomes and that loss of lysosomal Cacna1a in cerebellar cultured neurons leads to a failure of lysosomes to fuse with endosomes and autophagosomes. Finally, we show that the lysosomal CACNA1A but not the plasma-membrane resident CACNA1A is required for lysosomal fusion. In summary, we present a model in which the VGCC plays a role in autophagy by regulating the fusion of AVs with lysosomes through its calcium channel activity and hence functions in maintaining neuronal homeostasis. A voltage-gated calcium channel required for neurotransmitter release also regulates the fusion of neuronal lysosomes with endosomes and autophagosomes, thereby helping to maintain cellular homeostasis. Autophagy is a cellular process used by cells to prevent the accumulation of toxic substances. It delivers misfolded proteins and damaged organelles by fusing autophagosomes—organelles formed by a double membrane that surrounds the “debris” to be eliminated—with lysosomes. How this fusion process is regulated during autophagy, however, remains to be established. Here, we analyze this process in flies and mice, and find that loss of different subunits of a specific type of Voltage Gated Calcium Channel (VGCC) leads to defects in lysosomal fusion with autophagosomes in neurons. It was already known that VGCCs control calcium entry at synaptic terminals to promote the fusion of synaptic vesicles with the plasma membrane, and that mutations in the subunits of VGCCs in humans cause neurological diseases. Our data indicate that defects in autophagy and lysosomal fusion are independent of defects in synaptic vesicle fusion and neurotransmitter release, and we show that a specific VGCC is present on lysosomal membranes where it is required for lysosomal fusion with endosomes and autophagosomes. These observations suggest that the fusion events required in autophagy rely on mechanisms similar to those that trigger the fusion of synaptic vesicles with the presynaptic membrane.
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Affiliation(s)
- Xuejun Tian
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Upasana Gala
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yongping Zhang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Weina Shang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Marco Sardiello
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Roy V. Sillitoe
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Hengyu Fan
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (CT), (HJB)
| | - Chao Tong
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
- * E-mail: (CT), (HJB)
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14
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Wong CO, Chen K, Lin YQ, Chao Y, Duraine L, Lu Z, Yoon WH, Sullivan JM, Broadhead GT, Sumner CJ, Lloyd TE, Macleod GT, Bellen HJ, Venkatachalam K. A TRPV channel in Drosophila motor neurons regulates presynaptic resting Ca2+ levels, synapse growth, and synaptic transmission. Neuron 2014; 84:764-77. [PMID: 25451193 DOI: 10.1016/j.neuron.2014.09.030] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2014] [Indexed: 12/30/2022]
Abstract
Presynaptic resting Ca(2+) influences synaptic vesicle (SV) release probability. Here, we report that a TRPV channel, Inactive (Iav), maintains presynaptic resting [Ca(2+)] by promoting Ca(2+) release from the endoplasmic reticulum in Drosophila motor neurons, and is required for both synapse development and neurotransmission. We find that Iav activates the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin, which is essential for presynaptic microtubule stabilization at the neuromuscular junction. Thus, loss of Iav induces destabilization of presynaptic microtubules, resulting in diminished synaptic growth. Interestingly, expression of human TRPV1 in Iav-deficient motor neurons rescues these defects. We also show that the absence of Iav causes lower SV release probability and diminished synaptic transmission, whereas Iav overexpression elevates these synaptic parameters. Together, our findings indicate that Iav acts as a key regulator of synaptic development and function by influencing presynaptic resting [Ca(2+)].
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Affiliation(s)
- Ching-On Wong
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, 6431 Fannin Street, Houston, TX 77030, USA
| | - Kuchuan Chen
- Graduate Program in Developmental Biology, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA
| | - Yong Qi Lin
- Howard Hughes Medical Institute; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA
| | - Yufang Chao
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, 6431 Fannin Street, Houston, TX 77030, USA
| | - Lita Duraine
- Howard Hughes Medical Institute; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA
| | - Zhongmin Lu
- Integrative Biology and Neuroscience program, Florida Atlantic University and Max Planck Florida Institute, 5353 Parkside Drive, Jupiter, FL 33458, USA
| | - Wan Hee Yoon
- Howard Hughes Medical Institute; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA
| | - Jeremy M Sullivan
- Department of Neurology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21231, USA
| | - Geoffrey T Broadhead
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, 6431 Fannin Street, Houston, TX 77030, USA
| | - Charlotte J Sumner
- Department of Neurology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21231, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21231, USA
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21231, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21231, USA
| | - Gregory T Macleod
- Department of Physiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Hugo J Bellen
- Graduate Program in Developmental Biology, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA; Howard Hughes Medical Institute; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, 6431 Fannin Street, Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, 1250 Moursund Street, Suite N1125.14, Mailstop NR-1125, Houston, TX 77030, USA; Graduate Programs in Cell and Regulatory Biology (CRB) and Neuroscience, Graduate School of Biomedical Sciences, University of Texas School of Medicine, Houston, TX 77030.
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15
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Sandoval H, Yao CK, Chen K, Jaiswal M, Donti T, Lin YQ, Bayat V, Xiong B, Zhang K, David G, Charng WL, Yamamoto S, Duraine L, Graham BH, Bellen HJ. Mitochondrial fusion but not fission regulates larval growth and synaptic development through steroid hormone production. eLife 2014; 3. [PMID: 25313867 PMCID: PMC4215535 DOI: 10.7554/elife.03558] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial fusion and fission affect the distribution and quality control of mitochondria. We show that Marf (Mitochondrial associated regulatory factor), is required for mitochondrial fusion and transport in long axons. Moreover, loss of Marf leads to a severe depletion of mitochondria in neuromuscular junctions (NMJs). Marf mutants also fail to maintain proper synaptic transmission at NMJs upon repetitive stimulation, similar to Drp1 fission mutants. However, unlike Drp1, loss of Marf leads to NMJ morphology defects and extended larval lifespan. Marf is required to form contacts between the endoplasmic reticulum and/or lipid droplets (LDs) and for proper storage of cholesterol and ecdysone synthesis in ring glands. Interestingly, human Mitofusin-2 rescues the loss of LD but both Mitofusin-1 and Mitofusin-2 are required for steroid-hormone synthesis. Our data show that Marf and Mitofusins share an evolutionarily conserved role in mitochondrial transport, cholesterol ester storage and steroid-hormone synthesis. DOI:http://dx.doi.org/10.7554/eLife.03558.001 Mitochondria are the main source of energy for cells. These vital and highly dynamic organelles continually change shape by fusing with each other and splitting apart to create new mitochondria, repairing and replacing those damaged by cell stress. For nerve impulses to be transmitted across the gaps (called synapses) between nerve cells, mitochondria need to supply the very ends of the nerve fibers with energy. To do this, the mitochondria must be transported from the main body of the nerve cell to the tips of the nerve fibers. This may not happen if mitochondria are the wrong shape, size or damaged. While searching for genetic mutations that disrupt nerve function in the fruit fly Drosophila, Sandoval et al. spotted mutations in a gene called Marf. Further investigations revealed that flies with mutant versions of Marf have small, round mitochondria, and their nerves cannot transmit signals to muscles when they are highly stimulated. This is because the mutant mitochondria are not easily transported along nerve fibers, and so not enough energy is supplied to the synapses. The synapses of the Marf mutants are also abnormally shaped. Sandoval et al. found that this is not because Marf is lost in the neurons themselves, but because it is lost from a hormone-producing tissue called the ring gland. Another problem found in flies with mutated Marf genes is that they stop developing while in their larval stage. Sandoval et al. established that this could also be related to the loss of Marf from the ring gland. The Marf protein has two different functions in the ring gland: forming and storing droplets of fatty molecules used in hormone production, and synthesising a hormone that controls when a fly larva matures into the adult fly. This suggests that the lower levels of this hormone produced by Marf mutant flies underlies their prolonged larval stages and synapse defects. Vertebrates (animals with backbones, such as humans) have two genes that are related to the fly's Marf gene. When the human forms of these genes were introduced into mutant flies that lack a working copy of Marf, hormone production was only restored if both genes were introduced together. This indicates that these genes have separate roles in vertebrates, but that these roles are both performed by the single fly gene. The role of Marf in tethering mitochondria in the ring gland may allow us to better understand how this process affects hormone production and how the different parts of the cell communicate. DOI:http://dx.doi.org/10.7554/eLife.03558.002
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Affiliation(s)
- Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Chi-Kuang Yao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Taraka Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Yong Qi Lin
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, United States
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
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16
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Wang S, Tan KL, Agosto MA, Xiong B, Yamamoto S, Sandoval H, Jaiswal M, Bayat V, Zhang K, Charng WL, David G, Duraine L, Venkatachalam K, Wensel TG, Bellen HJ. The retromer complex is required for rhodopsin recycling and its loss leads to photoreceptor degeneration. PLoS Biol 2014; 12:e1001847. [PMID: 24781186 PMCID: PMC4004542 DOI: 10.1371/journal.pbio.1001847] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/21/2014] [Indexed: 12/22/2022] Open
Abstract
Rhodopsin recycling via the retromer, rather than degradation through lysosomes, can alleviate light-induced photoreceptor degeneration in Drosophila. Rhodopsin mistrafficking can cause photoreceptor (PR) degeneration. Upon light exposure, activated rhodopsin 1 (Rh1) in Drosophila PRs is internalized via endocytosis and degraded in lysosomes. Whether internalized Rh1 can be recycled is unknown. Here, we show that the retromer complex is expressed in PRs where it is required for recycling endocytosed Rh1 upon light stimulation. In the absence of subunits of the retromer, Rh1 is processed in the endolysosomal pathway, leading to a dramatic increase in late endosomes, lysosomes, and light-dependent PR degeneration. Reducing Rh1 endocytosis or Rh1 levels in retromer mutants alleviates PR degeneration. In addition, increasing retromer abundance suppresses degenerative phenotypes of mutations that affect the endolysosomal system. Finally, expressing human Vps26 suppresses PR degeneration in Vps26 mutant PRs. We propose that the retromer plays a conserved role in recycling rhodopsins to maintain PR function and integrity. Upon light exposure, rhodopsins—light-sensing proteins in the eye—trigger visual transduction signaling to activate fly photoreceptor cells. After activation, rhodopsins can be internalized from the cell surface into endosomes and then degraded in lysosomes. This mechanism prevents constant activation of the visual transduction pathway, thereby maintaining the function and integrity of photoreceptor cells. It is not known, however, whether these internalized rhodopsins can be recycled. Here, we show that the retromer, an evolutionarily conserved protein complex, is required for the recycling of rhodopsins. We find that loss of key retromer subunits (Vps35 or Vps26) causes rhodopsin mislocalization in the photoreceptors and severe light-induced photoreceptor degeneration. Conversely, gain of retromer subunits can alleviate photoreceptor degeneration in some contexts. Human retromer components can stand in for depleted fruit fly retromer, suggesting that this complex plays a role in recycling light sensors in both vertebrate and invertebrate photoreceptors.
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Affiliation(s)
- Shiuan Wang
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Melina A. Agosto
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lita Duraine
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Theodore G. Wensel
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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17
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Xiong B, Bayat V, Jaiswal M, Zhang K, Sandoval H, Charng WL, Li T, David G, Duraine L, Lin YQ, Neely GG, Yamamoto S, Bellen HJ. Crag is a GEF for Rab11 required for rhodopsin trafficking and maintenance of adult photoreceptor cells. PLoS Biol 2012; 10:e1001438. [PMID: 23226104 PMCID: PMC3514319 DOI: 10.1371/journal.pbio.1001438] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/22/2012] [Indexed: 11/29/2022] Open
Abstract
Transport of newly synthesized Rhodopsin upon light stimulation in adult Drosophila photoreceptors is mediated by a Crag/Rab11-dependent vesicular trafficking process. Rhodopsins (Rhs) are light sensors, and Rh1 is the major Rh in the Drosophila photoreceptor rhabdomere membrane. Upon photoactivation, a fraction of Rh1 is internalized and degraded, but it remains unclear how the rhabdomeric Rh1 pool is replenished and what molecular players are involved. Here, we show that Crag, a DENN protein, is a guanine nucleotide exchange factor for Rab11 that is required for the homeostasis of Rh1 upon light exposure. The absence of Crag causes a light-induced accumulation of cytoplasmic Rh1, and loss of Crag or Rab11 leads to a similar photoreceptor degeneration in adult flies. Furthermore, the defects associated with loss of Crag can be partially rescued with a constitutive active form of Rab11. We propose that upon light stimulation, Crag is required for trafficking of Rh from the trans-Golgi network to rhabdomere membranes via a Rab11-dependent vesicular transport. Animals sense light through receptors called Rhodopsins. These proteins are typically localized to stacked membranes in photoreceptors. In flies, upon light exposure, Rhodopsin undergoes conformational changes and becomes active as metarhodopsin. Metarhodopsin then initiates a signaling cascade that activates the photoreceptor cell. To deactivate the light response, metarhodopsin is converted back into Rhodopsin by absorption of another photon of light. Under certain conditions, metarhodopsin cannot be converted back to Rhodopsin, and it is then endocytosed and degraded. Rhodopsin then needs to be synthesized and delivered back to the membrane stacks. Here, we show that the Calmodulin-binding protein Crag is required for the delivery of newly made Rhodopsin to the membrane stacks. Loss of Crag leads to the accumulation of Rhodopsin in the cytosol, followed by shrinkage of membrane stack volume, and, eventually, photoreceptor cell degeneration. We also show that Crag activates a target protein, Rab11, which mediates the vesicular transport of Rhodospin to the membrane. Finally, we document that the human homolog of Crag, DENND4A, is able to rescue the loss of Crag in flies, suggesting that DENND4A functions in a similar process in vertebrates.
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Affiliation(s)
- Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States of America
| | - Manish Jaiswal
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yong-Qi Lin
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - G. Gregory Neely
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- Neurological Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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