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Jetti SK, Crane AB, Akbergenova Y, Aponte-Santiago NA, Cunningham KL, Whittaker CA, Littleton JT. Molecular logic of synaptic diversity between Drosophila tonic and phasic motoneurons. Neuron 2023; 111:3554-3569.e7. [PMID: 37611584 DOI: 10.1016/j.neuron.2023.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/22/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023]
Abstract
Although neuronal subtypes display unique synaptic organization and function, the underlying transcriptional differences that establish these features are poorly understood. To identify molecular pathways that contribute to synaptic diversity, single-neuron Patch-seq RNA profiling was performed on Drosophila tonic and phasic glutamatergic motoneurons. Tonic motoneurons form weaker facilitating synapses onto single muscles, while phasic motoneurons form stronger depressing synapses onto multiple muscles. Super-resolution microscopy and in vivo imaging demonstrated that synaptic active zones in phasic motoneurons are more compact and display enhanced Ca2+ influx compared with their tonic counterparts. Genetic analysis identified unique synaptic properties that mapped onto gene expression differences for several cellular pathways, including distinct signaling ligands, post-translational modifications, and intracellular Ca2+ buffers. These findings provide insights into how unique transcriptomes drive functional and morphological differences between neuronal subtypes.
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Affiliation(s)
- Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Andrés B Crane
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Charles A Whittaker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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2
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Vu Ho XA, Dao MU, Le TH, Chuong Nguyen TH, Nguyen Dinh MT, Nguyen QM, Tran TM, Huyen Nguyen TT, Ho TT, Nguyen HP, Nguyen CC. Development of Electro-Reduced AgNPs/MnO 2/rGO Composite toward a Robust Sensor for the Simultaneous Determination of Piroxicam and Ofloxacin. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c04610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Affiliation(s)
- Xuan Anh Vu Ho
- Hue University of Sciences, Hue University, Thua Thien Hue, Hue 530000, Vietnam
| | - My Uyen Dao
- Institute of Research and Development, Duy Tan University, Danang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Danang 550000, Vietnam
| | - Trung Hieu Le
- Hue University of Sciences, Hue University, Thua Thien Hue, Hue 530000, Vietnam
| | - Thi Hong Chuong Nguyen
- Institute of Research and Development, Duy Tan University, Danang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Danang 550000, Vietnam
| | - Minh Tuan Nguyen Dinh
- The University of Da Nang, University of Science and Technology, 54, Nguyen Luong Bang, Danang City 550000, Viet Nam
| | - Quang Man Nguyen
- University of Medicine and Pharmacy, Hue University, Hue City 530000, Vietnam
| | - Thanh Minh Tran
- Hue University of Sciences, Hue University, Thua Thien Hue, Hue 530000, Vietnam
| | - Thi Thanh Huyen Nguyen
- Institute of Research and Development, Duy Tan University, Danang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Danang 550000, Vietnam
| | - Thanh-Tam Ho
- Faculty of Natural Sciences, Duy Tan University, Danang 550000, Vietnam
- Institute for Global Health Innovations, Duy Tan University, Danang 550000, Vietnam
| | - Hai Phong Nguyen
- Hue University of Sciences, Hue University, Thua Thien Hue, Hue 530000, Vietnam
| | - Chinh Chien Nguyen
- Institute of Research and Development, Duy Tan University, Danang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Danang 550000, Vietnam
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3
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Jetti SK, Crane AB, Akbergenova Y, Aponte-Santiago NA, Cunningham KL, Whittaker CA, Littleton JT. Molecular Logic of Synaptic Diversity Between Drosophila Tonic and Phasic Motoneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524447. [PMID: 36711745 PMCID: PMC9882338 DOI: 10.1101/2023.01.17.524447] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Although neuronal subtypes display unique synaptic organization and function, the underlying transcriptional differences that establish these features is poorly understood. To identify molecular pathways that contribute to synaptic diversity, single neuron PatchSeq RNA profiling was performed on Drosophila tonic and phasic glutamatergic motoneurons. Tonic motoneurons form weaker facilitating synapses onto single muscles, while phasic motoneurons form stronger depressing synapses onto multiple muscles. Super-resolution microscopy and in vivo imaging demonstrated synaptic active zones in phasic motoneurons are more compact and display enhanced Ca 2+ influx compared to their tonic counterparts. Genetic analysis identified unique synaptic properties that mapped onto gene expression differences for several cellular pathways, including distinct signaling ligands, post-translational modifications and intracellular Ca 2+ buffers. These findings provide insights into how unique transcriptomes drive functional and morphological differences between neuronal subtypes.
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Affiliation(s)
- Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Andrés B Crane
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Charles A Whittaker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
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4
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HAT- and HDAC-Targeted Protein Acetylation in the Occurrence and Treatment of Epilepsy. Biomedicines 2022; 11:biomedicines11010088. [PMID: 36672596 PMCID: PMC9856006 DOI: 10.3390/biomedicines11010088] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/12/2022] [Accepted: 12/26/2022] [Indexed: 01/01/2023] Open
Abstract
Epilepsy is a common and severe chronic neurological disorder. Recently, post-translational modification (PTM) mechanisms, especially protein acetylation modifications, have been widely studied in various epilepsy models or patients. Acetylation is regulated by two classes of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs catalyze the transfer of the acetyl group to a lysine residue, while HDACs catalyze acetyl group removal. The expression of many genes related to epilepsy is regulated by histone acetylation and deacetylation. Moreover, the acetylation modification of some non-histone substrates is also associated with epilepsy. Various molecules have been developed as HDAC inhibitors (HDACi), which have become potential antiepileptic drugs for epilepsy treatment. In this review, we summarize the changes in acetylation modification in epileptogenesis and the applications of HDACi in the treatment of epilepsy as well as the mechanisms involved. As most of the published research has focused on the differential expression of proteins that are known to be acetylated and the knowledge of whole acetylome changes in epilepsy is still minimal, a further understanding of acetylation regulation will help us explore the pathological mechanism of epilepsy and provide novel ideas for treating epilepsy.
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Aspergillus fumigatus Elongator complex subunit 3 affects hyphal growth, adhesion and virulence through wobble uridine tRNA modification. PLoS Pathog 2022; 18:e1010976. [DOI: 10.1371/journal.ppat.1010976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 11/28/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
The eukaryotic multisubunit Elongator complex has been shown to perform multiple functions in transcriptional elongation, histone acetylation and tRNA modification. However, the Elongator complex plays different roles in different organisms, and the underlying mechanisms remain unexplored. Moreover, the biological functions of the Elongator complex in human fungal pathogens remain unknown. In this study, we verified that the Elongator complex of the opportunistic fungal pathogen Aspergillus fumigatus consists of six subunits (Elp1-6), and the loss of any subunit results in similarly defective colony phenotypes with impaired hyphal growth and reduced conidiation. The catalytic subunit-Elp3 of the Elongator complex includes a S-adenosyl methionine binding (rSAM) domain and a lysine acetyltransferase (KAT) domain, and it plays key roles in the hyphal growth, biofilm-associated exopolysaccharide galactosaminogalactan (GAG) production, adhesion and virulence of A. fumigatus; however, Elp3 does not affect H3K14 acetylation levels in vivo. LC–MS/MS chromatograms revealed that loss of Elp3 abolished the 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) modification of tRNA wobble uridine (U34), and the overexpression of tRNAGlnUUG and tRNAGluUUC, which normally harbor mcm5s2U modifications, mainly rescues the defects of the Δelp3 mutant, suggesting that tRNA modification rather than lysine acetyltransferase is responsible for the primary function of Elp3 in A. fumigatus. Strikingly, global proteomic comparison analyses showed significantly upregulated expression of genes related to amino acid metabolism in the Δelp3 mutant strain compared to the wild-type strain. Western blotting showed that deletion of elp3 resulted in overexpression of the amino acid starvation-responsive transcription factor CpcA, and deletion of CpcA markedly reversed the defective phenotypes of the Δelp3 mutant, including attenuated virulence. Therefore, the findings of this study demonstrate that A. fumigatus Elp3 functions as a tRNA-modifying enzyme in the regulation of growth, GAG production, adhesion and virulence by maintaining intracellular amino acid homeostasis. More broadly, our study highlights the importance of U34 tRNA modification in regulating cellular metabolic states and virulence traits of fungal pathogens.
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Elongator stabilizes microtubules to control central spindle asymmetry and polarized trafficking of cell fate determinants. Nat Cell Biol 2022; 24:1606-1616. [PMID: 36302967 PMCID: PMC7613801 DOI: 10.1038/s41556-022-01020-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 09/19/2022] [Indexed: 01/18/2023]
Abstract
Asymmetric cell division gives rise to two daughter cells that inherit different determinants, thereby acquiring different fates. Polarized trafficking of endosomes containing fate determinants recently emerged as an evolutionarily conserved feature of asymmetric cell division to enhance the robustness of asymmetric cell fate determination in flies, fish and mammals. In particular, polarized sorting of signalling endosomes by an asymmetric central spindle contributes to asymmetric cell division in Drosophila melanogaster. However, how central spindle asymmetry arises remains elusive. Here we identify a moonlighting function of the Elongator complex-an established protein acetylase and tRNA methylase involved in the fidelity of protein translation-as a key factor for central spindle asymmetry. Elongator controls spindle asymmetry by stabilizing microtubules differentially on the anterior side of the central spindle. Accordingly, lowering the activity of Elongator on the anterior side using nanobodies mistargets endosomes to the wrong cell. Molecularly, Elongator regulates microtubule dynamics independently of its acetylation and methylation enzymatic activities. Instead, Elongator directly binds to microtubules and increases their polymerization speed while decreasing their catastrophe frequency. Our data establish a non-canonical role of Elongator at the core of cytoskeleton polarity and asymmetric signalling.
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Shilian M, Even A, Gast H, Nguyen L, Weil M. Elongator promotes neuritogenesis via regulation of tau stability through acly activity. Front Cell Dev Biol 2022; 10:1015125. [PMID: 36393857 PMCID: PMC9644021 DOI: 10.3389/fcell.2022.1015125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/05/2022] [Indexed: 11/23/2022] Open
Abstract
The six subunits (Elp1 to Elp6) Elongator complex promotes specific uridine modifications in tRNA’s wobble site. Moreover, this complex has been indirectly involved in the regulation of α-tubulin acetylation in microtubules (MTs) via the stabilization of ATP-Citrate Lyase (Acly), the main cytosolic source of acetyl-CoA production in cells, a key substrate used for global protein acetylation. Here, we report additional evidence that Elongator activity is important for proper cytoskeleton remodeling as cells lacking expression of Elp1 show morphology impairment; including distinct neurite process formation and disorganization and instability of MTs. Here, we show that loss of Elongator results in a reduction of expression of the microtubule associated protein Tau (MAPT). Tau, is a well-known key MT regulator in neurons whose lysines can be competitively acetylated or ubiquitylated. Therefore, we tested whether Tau is an indirect acetylation target of Elongator. We found that a reduction of Elongator activity leads to a decrease of lysine acetylation on Tau that favors its proteasomal degradation. This phenotype was prevented by using selective deacetylase or proteasomal inhibitors. Moreover, our data demonstrate that Acly’s activity regulates the mechanism underlying Tau mediated neurite morphology defects found in Elp1 KD since both Tau levels and neurites morphology are restored due to Acly overexpression. This suggests a possible involvement of both Tau and Acly dysfunction in Familial Dysautonomia (FD), which is an autosomal recessive peripheral neuropathy caused by mutation in the ELP1 gene that severely affects Elp1 expression levels in the nervous system in FD patients in a similar way as found previously in Elp1 KD neuroblastoma cells.
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Affiliation(s)
- Michal Shilian
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty for Life Sciences, Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Aviel Even
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty for Life Sciences, Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Hila Gast
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty for Life Sciences, Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Laurent Nguyen
- GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGAR), University of Liège, C.H.U. Sart Tilman, Belgium, BIOMED Research Institute, Hasselt, Belgium
| | - Miguel Weil
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty for Life Sciences, Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
- *Correspondence: Miguel Weil,
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8
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Nair AG, Muttathukunnel P, Müller M. Distinct molecular pathways govern presynaptic homeostatic plasticity. Cell Rep 2021; 37:110105. [PMID: 34910905 PMCID: PMC8692748 DOI: 10.1016/j.celrep.2021.110105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 10/05/2021] [Accepted: 11/16/2021] [Indexed: 11/30/2022] Open
Abstract
Presynaptic homeostatic plasticity (PHP) stabilizes synaptic transmission by counteracting impaired neurotransmitter receptor function through neurotransmitter release potentiation. PHP is thought to be triggered by impaired receptor function and to involve a stereotypic signaling pathway. However, here we demonstrate that different receptor perturbations that similarly reduce synaptic transmission result in different responses at the Drosophila neuromuscular junction. While receptor inhibition by the glutamate receptor (GluR) antagonist γ-D-glutamylglycine (γDGG) is not compensated by PHP, the GluR inhibitors Philanthotoxin-433 (PhTx) and Gyki-53655 (Gyki) induce compensatory PHP. Intriguingly, PHP triggered by PhTx and Gyki involve separable signaling pathways, including inhibition of distinct GluR subtypes, differential modulation of the active-zone scaffold Bruchpilot, and short-term plasticity. Moreover, while PHP upon Gyki treatment does not require genes promoting PhTx-induced PHP, it involves presynaptic protein kinase D. Thus, synapses not only respond differentially to similar activity impairments, but achieve homeostatic compensation via distinct mechanisms, highlighting the diversity of homeostatic signaling.
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Affiliation(s)
- Anu G Nair
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden
| | - Paola Muttathukunnel
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich/ETH Zurich, 8057 Zurich, Switzerland
| | - Martin Müller
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich/ETH Zurich, 8057 Zurich, Switzerland.
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9
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ATP-citrate lyase promotes axonal transport across species. Nat Commun 2021; 12:5878. [PMID: 34620845 PMCID: PMC8497606 DOI: 10.1038/s41467-021-25786-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/24/2021] [Indexed: 01/22/2023] Open
Abstract
Microtubule (MT)-based transport is an evolutionary conserved process finely tuned by posttranslational modifications. Among them, α-tubulin acetylation, primarily catalyzed by a vesicular pool of α-tubulin N-acetyltransferase 1 (Atat1), promotes the recruitment and processivity of molecular motors along MT tracks. However, the mechanism that controls Atat1 activity remains poorly understood. Here, we show that ATP-citrate lyase (Acly) is enriched in vesicles and provide Acetyl-Coenzyme-A (Acetyl-CoA) to Atat1. In addition, we showed that Acly expression is reduced upon loss of Elongator activity, further connecting Elongator to Atat1 in a pathway regulating α-tubulin acetylation and MT-dependent transport in projection neurons, across species. Remarkably, comparable defects occur in fibroblasts from Familial Dysautonomia (FD) patients bearing an autosomal recessive mutation in the gene coding for the Elongator subunit ELP1. Our data may thus shine light on the pathophysiological mechanisms underlying FD. Microtubule tracks are important for the transport of molecules within axons. Here, the authors show that ATAT1, the enzyme responsible for acetylating a-tubulin, receives acetyl groups from ATP citrate lyase whose stability is regulated by Elongator, a protein mutated in the neuronal disease Familial dysautonomia.
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Goel P, Dickman D. Synaptic homeostats: latent plasticity revealed at the Drosophila neuromuscular junction. Cell Mol Life Sci 2021; 78:3159-3179. [PMID: 33449150 PMCID: PMC8044042 DOI: 10.1007/s00018-020-03732-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/19/2020] [Accepted: 12/04/2020] [Indexed: 12/11/2022]
Abstract
Homeostatic signaling systems are fundamental forms of biological regulation that maintain stable functionality in a changing environment. In the nervous system, synapses are crucial substrates for homeostatic modulation, serving to establish, maintain, and modify the balance of excitation and inhibition. Synapses must be sufficiently flexible to enable the plasticity required for learning and memory but also endowed with the stability to last a lifetime. In response to the processes of development, growth, remodeling, aging, and disease that challenge synapses, latent forms of adaptive plasticity become activated to maintain synaptic stability. In recent years, new insights into the homeostatic control of synaptic function have been achieved using the powerful Drosophila neuromuscular junction (NMJ). This review will focus on work over the past 10 years that has illuminated the cellular and molecular mechanisms of five homeostats that operate at the fly NMJ. These homeostats adapt to loss of postsynaptic neurotransmitter receptor functionality, glutamate imbalance, axonal injury, as well as aberrant synaptic growth and target innervation. These diverse homeostats work independently yet can be simultaneously expressed to balance neurotransmission. Growing evidence from this model glutamatergic synapse suggests these ancient homeostatic signaling systems emerged early in evolution and are fundamental forms of plasticity that also function to stabilize mammalian cholinergic NMJs and glutamatergic central synapses.
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Affiliation(s)
- Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA.
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11
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LoPresti P. HDAC6 in Diseases of Cognition and of Neurons. Cells 2020; 10:E12. [PMID: 33374719 PMCID: PMC7822434 DOI: 10.3390/cells10010012] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/12/2022] Open
Abstract
Central nervous system (CNS) neurodegenerative diseases are characterized by faulty intracellular transport, cognition, and aggregate regulation. Traditionally, neuroprotection exerted by histone deacetylase (HDAC) inhibitors (HDACi) has been attributed to the ability of this drug class to promote histone acetylation. However, HDAC6 in the healthy CNS functions via distinct mechanisms, due largely to its cytoplasmic localization. Indeed, in healthy neurons, cytoplasmic HDAC6 regulates the acetylation of a variety of non-histone proteins that are linked to separate functions, i.e., intracellular transport, neurotransmitter release, and aggregate formation. These three HDAC6 activities could work independently or in synergy. Of particular interest, HDAC6 targets the synaptic protein Bruchpilot and neurotransmitter release. In pathological conditions, HDAC6 becomes abundant in the nucleus, with deleterious consequences for transcription regulation and synapses. Thus, HDAC6 plays a leading role in neuronal health or dysfunction. Here, we review recent findings and novel conclusions on the role of HDAC6 in neurodegeneration. Selective studies with pan-HDACi are also included. We propose that an early alteration of HDAC6 undermines synaptic transmission, while altering transport and aggregation, eventually leading to neurodegeneration.
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Affiliation(s)
- Patrizia LoPresti
- Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street, Chicago, IL 60607, USA
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12
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Abbassi NEH, Biela A, Glatt S, Lin TY. How Elongator Acetylates tRNA Bases. Int J Mol Sci 2020; 21:E8209. [PMID: 33152999 PMCID: PMC7663514 DOI: 10.3390/ijms21218209] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/13/2022] Open
Abstract
Elp3, the catalytic subunit of the eukaryotic Elongator complex, is a lysine acetyltransferase that acetylates the C5 position of wobble-base uridines (U34) in transfer RNAs (tRNAs). This Elongator-dependent RNA acetylation of anticodon bases affects the ribosomal translation elongation rates and directly links acetyl-CoA metabolism to both protein synthesis rates and the proteome integrity. Of note, several human diseases, including various cancers and neurodegenerative disorders, correlate with the dysregulation of Elongator's tRNA modification activity. In this review, we focus on recent findings regarding the structure of Elp3 and the role of acetyl-CoA during its unique modification reaction.
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Affiliation(s)
- Nour-el-Hana Abbassi
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland; (N.-e.-H.A.); (A.B.)
- Postgraduate School of Molecular Medicine, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Anna Biela
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland; (N.-e.-H.A.); (A.B.)
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland; (N.-e.-H.A.); (A.B.)
| | - Ting-Yu Lin
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland; (N.-e.-H.A.); (A.B.)
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13
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Damulewicz M, Woźnicka O, Jasińska M, Pyza E. CRY-dependent plasticity of tetrad presynaptic sites in the visual system of Drosophila at the morning peak of activity and sleep. Sci Rep 2020; 10:18161. [PMID: 33097794 PMCID: PMC7585400 DOI: 10.1038/s41598-020-74442-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 09/22/2020] [Indexed: 11/09/2022] Open
Abstract
Tetrad synapses are formed between the retina photoreceptor terminals and postsynaptic cells in the first optic neuropil (lamina) of Drosophila. They are remodelled in the course of the day and show distinct functional changes during activity and sleep. These changes result from fast degradation of the presynaptic scaffolding protein Bruchpilot (BRP) by Cryptochrome (CRY) in the morning and depend on BRP-170, one of two BRP isoforms. This process also affects the number of synaptic vesicles, both clear and dense-core, delivered to the presynaptic elements. In cry01 mutants lacking CRY and in brpΔ170, the number of synaptic vesicles is lower in the morning peak of activity than during night-sleep while in wild-type flies the number of synaptic vesicles is similar at these two time points. CRY may also set phase of the circadian rhythm in plasticity of synapses. The process of synapse remodelling stimulates the formation of clear synaptic vesicles in the morning. They carry histamine, a neurotransmitter in tetrad synapses and seem to be formed from glial capitate projections inside the photoreceptor terminals. In turn dense-core vesicles probably carry synaptic proteins building the tetrad presynaptic element.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Olga Woźnicka
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Małgorzata Jasińska
- Department of Histology, Jagiellonian University Medical College, Kraków, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland.
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14
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Xia C, Tao Y, Li M, Che T, Qu J. Protein acetylation and deacetylation: An important regulatory modification in gene transcription (Review). Exp Ther Med 2020; 20:2923-2940. [PMID: 32855658 PMCID: PMC7444376 DOI: 10.3892/etm.2020.9073] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 04/24/2020] [Indexed: 12/16/2022] Open
Abstract
Cells primarily rely on proteins to perform the majority of their physiological functions, and the function of proteins is regulated by post-translational modifications (PTMs). The acetylation of proteins is a dynamic and highly specific PTM, which has an important influence on the functions of proteins, such as gene transcription and signal transduction. The acetylation of proteins is primarily dependent on lysine acetyltransferases and lysine deacetylases. In recent years, due to the widespread use of mass spectrometry and the emergence of new technologies, such as protein chips, studies on protein acetylation have been further developed. Compared with histone acetylation, acetylation of non-histone proteins has gradually become the focus of research due to its important regulatory mechanisms and wide range of applications. The discovery of specific protein acetylation sites using bioinformatic tools can greatly aid the understanding of the underlying mechanisms of protein acetylation involved in related physiological and pathological processes.
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Affiliation(s)
- Can Xia
- Department of Cell Biology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Yu Tao
- Department of Cell Biology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Mingshan Li
- Department of Cell Biology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Tuanjie Che
- Laboratory of Precision Medicine and Translational Medicine, Suzhou Hospital Affiliated to Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu 215153, P.R. China
| | - Jing Qu
- Department of Cell Biology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
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15
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Schäck MA, Jablonski KP, Gräf S, Klassen R, Schaffrath R, Kellner S, Hammann C. Eukaryotic life without tQCUG: the role of Elongator-dependent tRNA modifications in Dictyostelium discoideum. Nucleic Acids Res 2020; 48:7899-7913. [PMID: 32609816 PMCID: PMC7430636 DOI: 10.1093/nar/gkaa560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 12/23/2022] Open
Abstract
In the Elongator-dependent modification pathway, chemical modifications are introduced at the wobble uridines at position 34 in transfer RNAs (tRNAs), which serve to optimize codon translation rates. Here, we show that this three-step modification pathway exists in Dictyostelium discoideum, model of the evolutionary superfamily Amoebozoa. Not only are previously established modifications observable by mass spectrometry in strains with the most conserved genes of each step deleted, but also additional modifications are detected, indicating a certain plasticity of the pathway in the amoeba. Unlike described for yeast, D. discoideum allows for an unconditional deletion of the single tQCUG gene, as long as the Elongator-dependent modification pathway is intact. In gene deletion strains of the modification pathway, protein amounts are significantly reduced as shown by flow cytometry and Western blotting, using strains expressing different glutamine leader constructs fused to GFP. Most dramatic are these effects, when the tQCUG gene is deleted, or Elp3, the catalytic component of the Elongator complex is missing. In addition, Elp3 is the most strongly conserved protein of the modification pathway, as our phylogenetic analysis reveals. The implications of this observation are discussed with respect to the evolutionary age of the components acting in the Elongator-dependent modification pathway.
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Affiliation(s)
- Manfred A Schäck
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
| | - Kim Philipp Jablonski
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Roland Klassen
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Raffael Schaffrath
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Stefanie Kellner
- Department of Chemistry and Pharmacy, Ludwig-Maximilians University Munich, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Christian Hammann
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, DE 28759 Bremen, Germany
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16
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Plant Elongator-Protein Complex of Diverse Activities Regulates Growth, Development, and Immune Responses. Int J Mol Sci 2020; 21:ijms21186912. [PMID: 32971769 PMCID: PMC7555253 DOI: 10.3390/ijms21186912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 12/23/2022] Open
Abstract
Contrary to the conserved Elongator composition in yeast, animals, and plants, molecular functions and catalytic activities of the complex remain controversial. Elongator was identified as a component of elongating RNA polymerase II holoenzyme in yeast, animals, and plants. Furthermore, it was suggested that Elonagtor facilitates elongation of transcription via histone acetyl transferase activity. Accordingly, phenotypes of Arabidopsis elo mutants, which show development, growth, or immune response defects, correlate with transcriptional downregulation and the decreased histone acetylation in the coding regions of crucial genes. Plant Elongator was also implicated in other processes: transcription and processing of miRNA, regulation of DNA replication by histone acetylation, and acetylation of alpha-tubulin. Moreover, tRNA modification, discovered first in yeast and confirmed in plants, was claimed as the main activity of Elongator, leading to specificity in translation that might also result indirectly in a deficiency in transcription. Heterologous overexpression of individual Arabidopsis Elongator subunits and their respective phenotypes suggest that single Elongator subunits might also have another function next to being a part of the complex. In this review, we shall present the experimental evidence of all molecular mechanisms and catalytic activities performed by Elongator in nucleus and cytoplasm of plant cells, which might explain how Elongator regulates growth, development, and immune responses.
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17
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Rojas-Benítez D, L. Allende M. Elongator Subunit 3 (Elp3) Is Required for Zebrafish Trunk Development. Int J Mol Sci 2020; 21:E925. [PMID: 32023806 PMCID: PMC7036906 DOI: 10.3390/ijms21030925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/02/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022] Open
Abstract
Transfer RNAs (tRNAs) are the most post-transcriptionally modified RNA species. Some of these modifications, especially the ones located in the anti-codon loop, are required for decoding capabilities of tRNAs. Such is the case for 5-methoxy-carbonyl-methyl-2-thio-uridine (mcm5s2U), synthetized by the Elongator complex. Mutants for its sub-units display pleiotropic phenotypes. In this paper, we analyze the role of elp3 (Elongator catalytic sub-unit) in zebrafish development. We found that it is required for trunk development; elp3 knock-down animals presented diminished levels of mcm5s2U and sonic hedgehog (Shh) signaling activity. Activation of this pathway was sufficient to revert the phenotype caused by elp3 knockdown, indicating a functional relationship between Elongator and Shh through a yet unknown molecular mechanism.
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Affiliation(s)
- Diego Rojas-Benítez
- FONDAP Center for Genome Regulation (CGR), Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Ñuñoa, Santiago 7800003, Chile;
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18
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Yang KT, Inoue A, Lee YJ, Jiang CL, Lin FJ. Loss of Ikbkap/Elp1 in mouse oocytes causes spindle disorganization, developmental defects in preimplantation embryos and impaired female fertility. Sci Rep 2019; 9:18875. [PMID: 31827135 PMCID: PMC6906334 DOI: 10.1038/s41598-019-55090-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/23/2019] [Indexed: 01/08/2023] Open
Abstract
Elongator complexes are well known to be involved in a wide variety of cellular processes; however, their functions in mammalian oocytes have not been characterized. Here, we demonstrated in mice that specific deletion of one of the core subunits, Ikbkap/Elp1, in oocytes resulted in spindle defects and chromosome disorganization without affecting folliculogenesis. In accordance with these findings, we observed that Ikbkap mutant female mice are subfertile. Further analyses uncovered that kinetochore–microtubule attachments are severely compromised in Ikbkap-deficient oocytes. Moreover, we revealed that Ikbkap modulates the acetylation status of α-tubulin in oocytes, which may at least in part mediate the meiotic phenotypes described above by affecting microtubule dynamics and kinetochore function. Finally, we showed that embryos derived from Ikbkap-deficient oocytes exhibit an increased frequency of aneuploidy, digyny, progressive delays in preimplantation development, and severe degeneration before reaching the blastocyst stage. In summary, we identify Ikbkap as an important player in regulating oocyte meiosis by modulating tubulin acetylation for chromosome/spindle organization.
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Affiliation(s)
- Kuo-Tai Yang
- Department of Animal Science, National Pingtung University of Science and Technology, 91201, Pingtung, Taiwan
| | - Azusa Inoue
- Howard Hughes Medical Institute, Harvard Medical School, 02115, Boston, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA.,Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, 02115, USA.,RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan
| | - Yi-Jing Lee
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, 10617, Taiwan
| | - Chung-Lin Jiang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Fu-Jung Lin
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan. .,Research Center for Development Biology and Regenerative Medicine, National Taiwan University, Taipei, 10617, Taiwan.
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19
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Sheikh BN, Akhtar A. The many lives of KATs - detectors, integrators and modulators of the cellular environment. Nat Rev Genet 2019; 20:7-23. [PMID: 30390049 DOI: 10.1038/s41576-018-0072-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Research over the past three decades has firmly established lysine acetyltransferases (KATs) as central players in regulating transcription. Recent advances in genomic sequencing, metabolomics, animal models and mass spectrometry technologies have uncovered unexpected new roles for KATs at the nexus between the environment and transcriptional regulation. Thousands of reversible acetylation sites have been mapped in the proteome that respond dynamically to the cellular milieu and maintain major processes such as metabolism, autophagy and stress response. Concurrently, researchers are continuously uncovering how deregulation of KAT activity drives disease, including cancer and developmental syndromes characterized by severe intellectual disability. These novel findings are reshaping our view of KATs away from mere modulators of chromatin to detectors of the cellular environment and integrators of diverse signalling pathways with the ability to modify cellular phenotype.
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Affiliation(s)
- Bilal N Sheikh
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Asifa Akhtar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany.
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20
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Dystrobrevin is required postsynaptically for homeostatic potentiation at the Drosophila NMJ. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1579-1591. [PMID: 30904609 DOI: 10.1016/j.bbadis.2019.03.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 11/20/2022]
Abstract
Evolutionarily conserved homeostatic systems have been shown to modulate synaptic efficiency at the neuromuscular junctions of organisms. While advances have been made in identifying molecules that function presynaptically during homeostasis, limited information is currently available on how postsynaptic alterations affect presynaptic function. We previously identified a role for postsynaptic Dystrophin in the maintenance of evoked neurotransmitter release. We herein demonstrated that Dystrobrevin, a member of the Dystrophin Glycoprotein Complex, was delocalized from the postsynaptic region in the absence of Dystrophin. A newly-generated Dystrobrevin mutant showed elevated evoked neurotransmitter release, increased bouton numbers, and a readily releasable pool of synaptic vesicles without changes in the function or numbers of postsynaptic glutamate receptors. In addition, we provide evidence to show that the highly conserved Cdc42 Rho GTPase plays a key role in the postsynaptic Dystrophin/Dystrobrevin pathway for synaptic homeostasis. The present results give novel insights into the synaptic deficits underlying Duchenne Muscular Dystrophy affected by a dysfunctional Dystrophin Glycoprotein complex.
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21
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Russo A, Goel P, Brace EJ, Buser C, Dickman D, DiAntonio A. The E3 ligase Highwire promotes synaptic transmission by targeting the NAD-synthesizing enzyme dNmnat. EMBO Rep 2019; 20:e46975. [PMID: 30692130 PMCID: PMC6399608 DOI: 10.15252/embr.201846975] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/31/2018] [Accepted: 01/07/2019] [Indexed: 01/03/2023] Open
Abstract
The ubiquitin ligase Highwire restrains synaptic growth and promotes evoked neurotransmission at NMJ synapses in Drosophila Highwire regulates synaptic morphology by downregulating the MAP3K Wallenda, but excess Wallenda signaling does not account for the decreased presynaptic release observed in highwire mutants. Hence, Highwire likely has a second substrate that inhibits neurotransmission. Highwire targets the NAD+ biosynthetic and axoprotective enzyme dNmnat to regulate axonal injury responses. dNmnat localizes to synapses and interacts with the active zone protein Bruchpilot, leading us to hypothesize that Highwire promotes evoked release by downregulating dNmnat. Here, we show that excess dNmnat is necessary in highwire mutants and sufficient in wild-type larvae to reduce quantal content, likely via disruption of active zone ultrastructure. Catalytically active dNmnat is required to drive defects in evoked release, and depletion of a second NAD+ synthesizing enzyme is sufficient to suppress these defects in highwire mutants, suggesting that excess NAD+ biosynthesis is the mechanism inhibiting neurotransmission. Thus, Highwire downregulates dNmnat to promote evoked synaptic release, suggesting that Highwire balances the axoprotective and synapse-inhibitory functions of dNmnat.
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Affiliation(s)
- Alexandra Russo
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - E J Brace
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Chris Buser
- Oak Crest Institute of Science, Monrovia, CA, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
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22
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The Elongator subunit Elp3 is a non-canonical tRNA acetyltransferase. Nat Commun 2019; 10:625. [PMID: 30733442 PMCID: PMC6367351 DOI: 10.1038/s41467-019-08579-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/18/2019] [Indexed: 11/19/2022] Open
Abstract
The Elongator complex catalyzes posttranscriptional tRNA modifications by attaching carboxy-methyl (cm5) moieties to uridine bases located in the wobble position. The catalytic subunit Elp3 is highly conserved and harbors two individual subdomains, a radical S-adenosyl methionine (rSAM) and a lysine acetyltransferase (KAT) domain. The details of its modification reaction cycle and particularly the substrate specificity of its KAT domain remain elusive. Here, we present the co-crystal structure of bacterial Elp3 (DmcElp3) bound to an acetyl-CoA analog and compare it to the structure of a monomeric archaeal Elp3 from Methanocaldococcus infernus (MinElp3). Furthermore, we identify crucial active site residues, confirm the importance of the extended N-terminus for substrate recognition and uncover the specific induction of acetyl-CoA hydrolysis by different tRNA species. In summary, our results establish the clinically relevant Elongator subunit as a non-canonical acetyltransferase and genuine tRNA modification enzyme. Elp3 is the catalytic subunit of the eukaryotic Elongator complex that catalyzes posttranscriptional tRNA modifications. Here the authors present the crystal structures of an acetyl-CoA analog bound bacterial Elp3 and a monomeric archaeal Elp3 and show that Elp3 functions as a tRNA modification enzyme in all domains of life.
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23
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Bento-Abreu A, Jager G, Swinnen B, Rué L, Hendrickx S, Jones A, Staats KA, Taes I, Eykens C, Nonneman A, Nuyts R, Timmers M, Silva L, Chariot A, Nguyen L, Ravits J, Lemmens R, Cabooter D, Van Den Bosch L, Van Damme P, Al-Chalabi A, Bystrom A, Robberecht W. Elongator subunit 3 (ELP3) modifies ALS through tRNA modification. Hum Mol Genet 2019; 27:1276-1289. [PMID: 29415125 PMCID: PMC6159532 DOI: 10.1093/hmg/ddy043] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal degenerative motor neuron disorder of which the progression is influenced by several disease-modifying factors. Here, we investigated ELP3, a subunit of the elongator complex that modifies tRNA wobble uridines, as one of such ALS disease modifiers. ELP3 attenuated the axonopathy of a mutant SOD1, as well as of a mutant C9orf72 ALS zebrafish model. Furthermore, the expression of ELP3 in the SOD1G93A mouse extended the survival and attenuated the denervation in this model. Depletion of ELP3 in vitro reduced the modified tRNA wobble uridine mcm5s2U and increased abundance of insoluble mutant SOD1, which was reverted by exogenous ELP3 expression. Interestingly, the expression of ELP3 in the motor cortex of ALS patients was reduced and correlated with mcm5s2U levels. Our results demonstrate that ELP3 is a modifier of ALS and suggest a link between tRNA modification and neurodegeneration.
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Affiliation(s)
- Andre Bento-Abreu
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Gunilla Jager
- Department of Molecular Biology, Umeå University, Umeå 901 87, Sweden
| | - Bart Swinnen
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, B-3000 Leuven, Belgium
| | - Laura Rué
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Stijn Hendrickx
- Department of Pharmaceutical & Pharmacological Sciences, Pharmaceutical Analysis, B-3000 Leuven, Belgium
| | - Ashley Jones
- Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Kim A Staats
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Ines Taes
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Caroline Eykens
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Annelies Nonneman
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Rik Nuyts
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Mieke Timmers
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Lara Silva
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Alain Chariot
- GIGA-Molecular Biology of Diseases and Walloon Excellence in Life Sciences and Biotechnology (WELBIO), C.H.U. Sart Tilman, B-4000 Liège, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, B-4000 Liège, Belgium
| | - John Ravits
- Department of Neurosciences, ALS Translational Research, University of California, San Diego, La Jolla, CA, USA
| | - Robin Lemmens
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, B-3000 Leuven, Belgium
| | - Deirdre Cabooter
- Department of Pharmaceutical & Pharmacological Sciences, Pharmaceutical Analysis, B-3000 Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Laboratory of Neurobiology, VIB-Center for Brain & Disease Research, B-3000 Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, B-3000 Leuven, Belgium
| | - Ammar Al-Chalabi
- Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Anders Bystrom
- Department of Molecular Biology, Umeå University, Umeå 901 87, Sweden
| | - Wim Robberecht
- Department of Neurosciences, Experimental Neurology and Leuven Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, B-3000 Leuven, Belgium
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24
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Levels of Par-1 kinase determine the localization of Bruchpilot at the Drosophila neuromuscular junction synapses. Sci Rep 2018; 8:16099. [PMID: 30382129 PMCID: PMC6208417 DOI: 10.1038/s41598-018-34250-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/21/2018] [Indexed: 12/11/2022] Open
Abstract
Functional synaptic networks are compromised in many neurodevelopmental and neurodegenerative diseases. While the mechanisms of axonal transport and localization of synaptic vesicles and mitochondria are relatively well studied, little is known about the mechanisms that regulate the localization of proteins that localize to active zones. Recent finding suggests that mechanisms involved in transporting proteins destined to active zones are distinct from those that transport synaptic vesicles or mitochondria. Here we report that localization of BRP-an essential active zone scaffolding protein in Drosophila, depends on the precise balance of neuronal Par-1 kinase. Disruption of Par-1 levels leads to excess accumulation of BRP in axons at the expense of BRP at active zones. Temporal analyses demonstrate that accumulation of BRP within axons precedes the loss of synaptic function and its depletion from the active zones. Mechanistically, we find that Par-1 co-localizes with BRP and is present in the same molecular complex, raising the possibility of a novel mechanism for selective localization of BRP-like active zone scaffolding proteins. Taken together, these data suggest an intriguing possibility that mislocalization of active zone proteins like BRP might be one of the earliest signs of synapse perturbation and perhaps, synaptic networks that precede many neurological disorders.
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25
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Yu D, Tan Y, Chakraborty M, Tomchik S, Davis RL. Elongator complex is required for long-term olfactory memory formation in Drosophila. Learn Mem 2018; 25:183-196. [PMID: 29545390 PMCID: PMC5855525 DOI: 10.1101/lm.046557.117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/12/2018] [Indexed: 12/13/2022]
Abstract
The evolutionarily conserved Elongator Complex associates with RNA polymerase II for transcriptional elongation. Elp3 is the catalytic subunit, contains histone acetyltransferase activity, and is associated with neurodegeneration in humans. Elp1 is a scaffolding subunit and when mutated causes familial dysautonomia. Here, we show that elp3 and elp1 are required for aversive long-term olfactory memory in Drosophila RNAi knockdown of elp3 in adult mushroom bodies impairs long-term memory (LTM) without affecting earlier forms of memory. RNAi knockdown with coexpression of elp3 cDNA reverses the impairment. Similarly, RNAi knockdown of elp1 impairs LTM and coexpression of elp1 cDNA reverses this phenotype. The LTM deficit in elp3 and elp1 knockdown flies is accompanied by the abolishment of a LTM trace, which is registered as increased calcium influx in response to the CS+ odor in the α-branch of mushroom body neurons. Coexpression of elp1 or elp3 cDNA rescues the memory trace in parallel with LTM. These data show that the Elongator complex is required in adult mushroom body neurons for long-term behavioral memory and the associated long-term memory trace.
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Affiliation(s)
- Dinghui Yu
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Ying Tan
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Molee Chakraborty
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, Florida 33458, USA
| | - Seth Tomchik
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, Florida 33458, USA
| | - Ronald L Davis
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, Florida 33458, USA
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26
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Marelja Z, Leimkühler S, Missirlis F. Iron Sulfur and Molybdenum Cofactor Enzymes Regulate the Drosophila Life Cycle by Controlling Cell Metabolism. Front Physiol 2018; 9:50. [PMID: 29491838 PMCID: PMC5817353 DOI: 10.3389/fphys.2018.00050] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
Iron sulfur (Fe-S) clusters and the molybdenum cofactor (Moco) are present at enzyme sites, where the active metal facilitates electron transfer. Such enzyme systems are soluble in the mitochondrial matrix, cytosol and nucleus, or embedded in the inner mitochondrial membrane, but virtually absent from the cell secretory pathway. They are of ancient evolutionary origin supporting respiration, DNA replication, transcription, translation, the biosynthesis of steroids, heme, catabolism of purines, hydroxylation of xenobiotics, and cellular sulfur metabolism. Here, Fe-S cluster and Moco biosynthesis in Drosophila melanogaster is reviewed and the multiple biochemical and physiological functions of known Fe-S and Moco enzymes are described. We show that RNA interference of Mocs3 disrupts Moco biosynthesis and the circadian clock. Fe-S-dependent mitochondrial respiration is discussed in the context of germ line and somatic development, stem cell differentiation and aging. The subcellular compartmentalization of the Fe-S and Moco assembly machinery components and their connections to iron sensing mechanisms and intermediary metabolism are emphasized. A biochemically active Fe-S core complex of heterologously expressed fly Nfs1, Isd11, IscU, and human frataxin is presented. Based on the recent demonstration that copper displaces the Fe-S cluster of yeast and human ferredoxin, an explanation for why high dietary copper leads to cytoplasmic iron deficiency in flies is proposed. Another proposal that exosomes contribute to the transport of xanthine dehydrogenase from peripheral tissues to the eye pigment cells is put forward, where the Vps16a subunit of the HOPS complex may have a specialized role in concentrating this enzyme within pigment granules. Finally, we formulate a hypothesis that (i) mitochondrial superoxide mobilizes iron from the Fe-S clusters in aconitase and succinate dehydrogenase; (ii) increased iron transiently displaces manganese on superoxide dismutase, which may function as a mitochondrial iron sensor since it is inactivated by iron; (iii) with the Krebs cycle thus disrupted, citrate is exported to the cytosol for fatty acid synthesis, while succinyl-CoA and the iron are used for heme biosynthesis; (iv) as iron is used for heme biosynthesis its concentration in the matrix drops allowing for manganese to reactivate superoxide dismutase and Fe-S cluster biosynthesis to reestablish the Krebs cycle.
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Affiliation(s)
- Zvonimir Marelja
- Imagine Institute, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Silke Leimkühler
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Fanis Missirlis
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
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27
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Ehmann N, Owald D, Kittel RJ. Drosophila active zones: From molecules to behaviour. Neurosci Res 2018; 127:14-24. [DOI: 10.1016/j.neures.2017.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 11/15/2022]
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28
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Pandey H, Bourahmoune K, Honda T, Honjo K, Kurita K, Sato T, Sawa A, Furukubo-Tokunaga K. Genetic interaction of DISC1 and Neurexin in the development of fruit fly glutamatergic synapses. NPJ SCHIZOPHRENIA 2017; 3:39. [PMID: 29079805 PMCID: PMC5660244 DOI: 10.1038/s41537-017-0040-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 09/19/2017] [Accepted: 09/27/2017] [Indexed: 12/31/2022]
Abstract
Originally identified at the breakpoint of a (1;11)(q42.1; q14.3) chromosomal translocation in a Scottish family with a wide range of mental disorders, the DISC1 gene has been a focus of intensive investigations as an entry point to study the molecular mechanisms of diverse mental dysfunctions. Perturbations of the DISC1 functions lead to behavioral changes in animal models, which are relevant to psychiatric conditions in patients. In this work, we have expressed the human DISC1 gene in the fruit fly (Drosophila melanogaster) and performed a genetic screening for the mutations of psychiatric risk genes that cause modifications of DISC1 synaptic phenotypes at the neuromuscular junction. We found that DISC1 interacts with dnrx1, the Drosophila homolog of the human Neurexin (NRXN1) gene, in the development of glutamatergic synapses. While overexpression of DISC1 suppressed the total bouton area on the target muscles and stimulated active zone density in wild-type background, a partial reduction of the dnrx1 activity negated the DISC1–mediated synaptic alterations. Likewise, overexpression of DISC1 stimulated the expression of a glutamate receptor component, DGLURIIA, in wild-type background but not in the dnrx1 heterozygous background. In addition, DISC1 caused mislocalization of Discs large, the Drosophila PSD-95 homolog, in the dnrx1 heterozygous background. Analyses with a series of domain deletions have revealed the importance of axonal localization of the DISC1 protein for efficient suppression of DNRX1 in synaptic boutons. These results thus suggest an intriguing converging mechanism controlled by the interaction of DISC1 and Neurexin in the developing glutamatergic synapses. Fruit fly models uncover a potential new mechanism by which two schizophrenia risk factor genes interact to alter synaptic junctions. DISC1 gene alterations have previously been linked to psychiatric anomalies, although the gene has not been formally recognized as a schizophrenia risk factor. A US-Japan research collaboration led by the University of Tsukuba’s Katsuo Furukubo-Tokunaga expressed human DISC1 in fruit fly synapses to better understand the changes that take place when gene disruption leads to overexpression. The team found that overexpression of DISC1 affected the expression of the fruit fly counterpart to human ‘neurexin,’ a known risk factor for conditions including schizophrenia and autism spectrum disorders. The interaction between neurexin and DISC1 also influenced other synapse-altering genes. Further research is warranted to explore the roles of DISC1 and neurexin in psychiatric disease.
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Affiliation(s)
- Himani Pandey
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Katia Bourahmoune
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Takato Honda
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Ken Honjo
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Kazuki Kurita
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Tomohito Sato
- Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan
| | - Akira Sawa
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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29
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Dauden MI, Jaciuk M, Müller CW, Glatt S. Structural asymmetry in the eukaryotic Elongator complex. FEBS Lett 2017; 592:502-515. [DOI: 10.1002/1873-3468.12865] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/08/2017] [Accepted: 09/24/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Maria I. Dauden
- Structural and Computational Biology Unit European Molecular Biology Laboratory Heidelberg Germany
| | - Marcin Jaciuk
- Max Planck Research Group at the Malopolska Centre of Biotechnology Jagiellonian University Krakow Poland
| | - Christoph W. Müller
- Structural and Computational Biology Unit European Molecular Biology Laboratory Heidelberg Germany
| | - Sebastian Glatt
- Max Planck Research Group at the Malopolska Centre of Biotechnology Jagiellonian University Krakow Poland
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30
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Laguesse S, Close P, Van Hees L, Chariot A, Malgrange B, Nguyen L. Loss of Elp3 Impairs the Acetylation and Distribution of Connexin-43 in the Developing Cerebral Cortex. Front Cell Neurosci 2017; 11:122. [PMID: 28507509 PMCID: PMC5410572 DOI: 10.3389/fncel.2017.00122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/12/2017] [Indexed: 12/19/2022] Open
Abstract
The Elongator complex is required for proper development of the cerebral cortex. Interfering with its activity in vivo delays the migration of postmitotic projection neurons, at least through a defective α-tubulin acetylation. However, this complex is already expressed by cortical progenitors where it may regulate the early steps of migration by targeting additional proteins. Here we report that connexin-43 (Cx43), which is strongly expressed by cortical progenitors and whose depletion impairs projection neuron migration, requires Elongator expression for its proper acetylation. Indeed, we show that Cx43 acetylation is reduced in the cortex of Elp3cKO embryos, as well as in a neuroblastoma cell line depleted of Elp1 expression, suggesting that Cx43 acetylation requires Elongator in different cellular contexts. Moreover, we show that histones deacetylase 6 (HDAC6) is a deacetylase of Cx43. Finally, we report that acetylation of Cx43 regulates its membrane distribution in apical progenitors of the cerebral cortex.
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Affiliation(s)
- Sophie Laguesse
- GIGA-Neurosciences, University of LiègeLiège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium
| | - Pierre Close
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium.,GIGA-Molecular Biology of Diseases, University of LiègeLiège, Belgium
| | - Laura Van Hees
- GIGA-Neurosciences, University of LiègeLiège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium
| | - Alain Chariot
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium.,GIGA-Molecular Biology of Diseases, University of LiègeLiège, Belgium.,Walloon Excellence in Lifesciences and Biotechnology (WELBIO)Wallonia, Belgium
| | - Brigitte Malgrange
- GIGA-Neurosciences, University of LiègeLiège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, University of LiègeLiège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of LiègeLiège, Belgium
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31
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Perry S, Kiragasi B, Dickman D, Ray A. The Role of Histone Deacetylase 6 in Synaptic Plasticity and Memory. Cell Rep 2017; 18:1337-1345. [PMID: 28178513 PMCID: PMC5387061 DOI: 10.1016/j.celrep.2017.01.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 10/28/2016] [Accepted: 01/12/2017] [Indexed: 02/02/2023] Open
Abstract
Histone deacetylases (HDACs) have been extensively studied as drug targets in neurodegenerative diseases, but less is known about their role in healthy neurons. We tested zinc-dependent HDACs using RNAi in Drosophila melanogaster and found memory deficits with RPD3 and HDAC6. We demonstrate that HDAC6 is required in both the larval and adult stages for normal olfactory memory retention. Neuronal expression of HDAC6 rescued memory deficits, and we demonstrate that the N-terminal deacetylase (DAC) domain is required for this ability. This suggests that deacetylation of synaptic targets associated with the first DAC domain, such as the active-zone scaffold Bruchpilot, is required for memory retention. Finally, electrophysiological experiments at the neuromuscular junction reveal that HDAC6 mutants exhibit a partial block of homeostatic plasticity, suggesting that HDAC6 may be required for the stabilization of synaptic strength. The learning deficit we observe in HDAC6 mutants could be a behavioral consequence of these synaptic defects.
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Affiliation(s)
- Sarah Perry
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, Riverside, CA 92521, USA
| | - Beril Kiragasi
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Anandasankar Ray
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, Riverside, CA 92521, USA; Center for Disease Vector Research, University of California, Riverside, Riverside, CA 92521, USA.
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32
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Kolaj-Robin O, Séraphin B. Structures and Activities of the Elongator Complex and Its Cofactors. RNA MODIFICATION 2017; 41:117-149. [DOI: 10.1016/bs.enz.2017.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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33
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Bruckner JJ, Zhan H, Gratz SJ, Rao M, Ukken F, Zilberg G, O'Connor-Giles KM. Fife organizes synaptic vesicles and calcium channels for high-probability neurotransmitter release. J Cell Biol 2016; 216:231-246. [PMID: 27998991 PMCID: PMC5223599 DOI: 10.1083/jcb.201601098] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 10/19/2016] [Accepted: 11/29/2016] [Indexed: 11/22/2022] Open
Abstract
Fife is a Piccolo-RIM–related protein that regulates neurotransmission and motor behavior through an unknown mechanism. Here, Bruckner et al. show that Fife organizes synaptic vesicle docking and coupling to calcium channels to establish and modulate synaptic strength. The strength of synaptic connections varies significantly and is a key determinant of communication within neural circuits. Mechanistic insight into presynaptic factors that establish and modulate neurotransmitter release properties is crucial to understanding synapse strength, circuit function, and neural plasticity. We previously identified Drosophila Piccolo-RIM-related Fife, which regulates neurotransmission and motor behavior through an unknown mechanism. Here, we demonstrate that Fife localizes and interacts with RIM at the active zone cytomatrix to promote neurotransmitter release. Loss of Fife results in the severe disruption of active zone cytomatrix architecture and molecular organization. Through electron tomographic and electrophysiological studies, we find a decrease in the accumulation of release-ready synaptic vesicles and their release probability caused by impaired coupling to Ca2+ channels. Finally, we find that Fife is essential for the homeostatic modulation of neurotransmission. We propose that Fife organizes active zones to create synaptic vesicle release sites within nanometer distance of Ca2+ channel clusters for reliable and modifiable neurotransmitter release.
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Affiliation(s)
- Joseph J Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Hong Zhan
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Scott J Gratz
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Monica Rao
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Fiona Ukken
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Gregory Zilberg
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Kate M O'Connor-Giles
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706 .,Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706.,Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
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34
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Makins C, Ghosh S, Román-Meléndez GD, Malec PA, Kennedy RT, Marsh ENG. Does Viperin Function as a Radical S-Adenosyl-l-methionine-dependent Enzyme in Regulating Farnesylpyrophosphate Synthase Expression and Activity? J Biol Chem 2016; 291:26806-26815. [PMID: 27834682 DOI: 10.1074/jbc.m116.751040] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/31/2016] [Indexed: 01/09/2023] Open
Abstract
Viperin is an endoplasmic reticulum-associated antiviral responsive protein that is highly up-regulated in eukaryotic cells upon viral infection through both interferon-dependent and independent pathways. Viperin is predicted to be a radical S-adenosyl-l-methionine (SAM) enzyme, but it is unknown whether viperin actually exploits radical SAM chemistry to exert its antiviral activity. We have investigated the interaction of viperin with its most firmly established cellular target, farnesyl pyrophosphate synthase (FPPS). Numerous enveloped viruses utilize cholesterol-rich lipid rafts to bud from the host cell membrane, and it is thought that by inhibiting FPPS activity (and therefore cholesterol synthesis), viperin retards viral budding from infected cells. We demonstrate that, consistent with this hypothesis, overexpression of viperin in human embryonic kidney cells reduces the intracellular rate of accumulation of FPPS but does not inhibit or inactivate FPPS. The endoplasmic reticulum-localizing, N-terminal amphipathic helix of viperin is specifically required for viperin to reduce cellular FPPS levels. However, although viperin reductively cleaves SAM to form 5'-deoxyadenosine in a slow, uncoupled reaction characteristic of radical SAM enzymes, this cleavage reaction is independent of FPPS. Furthermore, mutation of key cysteinyl residues ligating the catalytic [Fe4S4] cluster in the radical SAM domain, surprisingly, does not abolish the inhibitory activity of viperin against FPPS; indeed, some mutations potentiate viperin activity. These observations imply that viperin does not act as a radical SAM enzyme in regulating FPPS.
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Affiliation(s)
- Caitlyn Makins
- From the Departments of Chemistry and.,Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | | | | | | | | | - E Neil G Marsh
- From the Departments of Chemistry and .,Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
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35
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Kojic M, Wainwright B. The Many Faces of Elongator in Neurodevelopment and Disease. Front Mol Neurosci 2016; 9:115. [PMID: 27847465 PMCID: PMC5088202 DOI: 10.3389/fnmol.2016.00115] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 10/18/2016] [Indexed: 12/02/2022] Open
Abstract
Development of the nervous system requires a variety of cellular activities, such as proliferation, migration, axonal outgrowth and guidance and synapse formation during the differentiation of neural precursors into mature neurons. Malfunction of these highly regulated and coordinated events results in various neurological diseases. The Elongator complex is a multi-subunit complex highly conserved in eukaryotes whose function has been implicated in the majority of cellular activities underlying neurodevelopment. These activities include cell motility, actin cytoskeleton organization, exocytosis, polarized secretion, intracellular trafficking and the maintenance of neural function. Several studies have associated mutations in Elongator subunits with the neurological disorders familial dysautonomia (FD), intellectual disability (ID), amyotrophic lateral sclerosis (ALS) and rolandic epilepsy (RE). Here, we review the various cellular activities assigned to this complex and discuss the implications for neural development and disease. Further research in this area has the potential to generate new diagnostic tools, better prevention strategies and more effective treatment options for a wide variety of neurological disorders.
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Affiliation(s)
- Marija Kojic
- Genomics of Development and Disease Division, Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, Australia
| | - Brandon Wainwright
- Genomics of Development and Disease Division, Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, Australia
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36
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Epigenetic Regulation of SNAP25 Prevents Progressive Glutamate Excitotoxicty in Hypoxic CA3 Neurons. Mol Neurobiol 2016; 54:6133-6147. [PMID: 27699604 DOI: 10.1007/s12035-016-0156-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/22/2016] [Indexed: 01/31/2023]
Abstract
Exposure to global hypoxia and ischemia has been reported to cause neurodegeneration in the hippocampus with CA3 neurons. This neuronal damage is progressive during the initial phase of exposure but maintains a plateau on prolonged exposure. The present study on Sprague Dawley rats aimed at understanding the underlying molecular and epigenetic mechanisms that lead to hypoxic adaptation of CA3 neurons on prolonged exposure to a global hypoxia. Our results show stagnancy in neurodegeneration in CA3 region beyond 14 days of chronic exposure to hypobaria simulating an altitude of 25,000 ft. Despite increased synaptosomal glutamate and higher expression of NR1 subunit of NMDA receptors, we observed decrease in post-synaptic density and accumulation of synaptic vesicles at the pre-synaptic terminals. Molecular investigations involving western blot and real-time PCR showed duration-dependent decrease in the expression of SNAP-25 resulting in reduced vesicular docking and synaptic remodeling. ChIP assays for epigenetic factors showed decreased expression of H3K9Ac and H3K14Ac resulting in SNAP-25 promoter silencing during prolonged hypoxia. Administration of sodium butyrate, a non-specific HDAC inhibitor, during 21 days hypoxic exposure prevented SNAP-25 downregulation but increased CA3 neurodegeneration. This epigenetic regulation of SNAP-25 promoter was independent of increased DNMT3b expression and promoter methylation. Our findings provide a novel insight into epigenetic factors-mediated synaptic remodeling to prevent excitotoxic neurodegeneration on prolonged exposure to global hypobaric hypoxia.
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37
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Tielens S, Huysseune S, Godin JD, Chariot A, Malgrange B, Nguyen L. Elongator controls cortical interneuron migration by regulating actomyosin dynamics. Cell Res 2016; 26:1131-1148. [PMID: 27670698 DOI: 10.1038/cr.2016.112] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 06/27/2016] [Accepted: 08/11/2016] [Indexed: 12/20/2022] Open
Abstract
The migration of cortical interneurons is a fundamental process for the establishment of cortical connectivity and its impairment underlies several neurological disorders. During development, these neurons are born in the ganglionic eminences and they migrate tangentially to populate the cortical layers. This process relies on various morphological changes that are driven by dynamic cytoskeleton remodelings. By coupling time lapse imaging with molecular analyses, we show that the Elongator complex controls cortical interneuron migration in mouse embryos by regulating nucleokinesis and branching dynamics. At the molecular level, Elongator fine-tunes actomyosin forces by regulating the distribution and turnover of actin microfilaments during cell migration. Thus, we demonstrate that Elongator cell-autonomously promotes cortical interneuron migration by controlling actin cytoskeletal dynamics.
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Affiliation(s)
- Sylvia Tielens
- GIGA-Neurosciences, 4000 Liège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium
| | - Sandra Huysseune
- GIGA-Neurosciences, 4000 Liège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium
| | - Juliette D Godin
- GIGA-Neurosciences, 4000 Liège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium
| | - Alain Chariot
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium.,GIGA-Molecular Biology of Diseases, 4000 Liège, Belgium.,Walloon Excellence in Lifesciences and Biotechnology (WELBIO), University of Liège, CHU Sart Tilman, 4000 Liège, Belgium
| | - Brigitte Malgrange
- GIGA-Neurosciences, 4000 Liège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, 4000 Liège, Belgium.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), 4000 Liège, Belgium
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38
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Gupta VK, Pech U, Bhukel A, Fulterer A, Ender A, Mauermann SF, Andlauer TFM, Antwi-Adjei E, Beuschel C, Thriene K, Maglione M, Quentin C, Bushow R, Schwärzel M, Mielke T, Madeo F, Dengjel J, Fiala A, Sigrist SJ. Spermidine Suppresses Age-Associated Memory Impairment by Preventing Adverse Increase of Presynaptic Active Zone Size and Release. PLoS Biol 2016; 14:e1002563. [PMID: 27684064 PMCID: PMC5042543 DOI: 10.1371/journal.pbio.1002563] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 08/26/2016] [Indexed: 01/24/2023] Open
Abstract
Memories are assumed to be formed by sets of synapses changing their structural or functional performance. The efficacy of forming new memories declines with advancing age, but the synaptic changes underlying age-induced memory impairment remain poorly understood. Recently, we found spermidine feeding to specifically suppress age-dependent impairments in forming olfactory memories, providing a mean to search for synaptic changes involved in age-dependent memory impairment. Here, we show that a specific synaptic compartment, the presynaptic active zone (AZ), increases the size of its ultrastructural elaboration and releases significantly more synaptic vesicles with advancing age. These age-induced AZ changes, however, were fully suppressed by spermidine feeding. A genetically enforced enlargement of AZ scaffolds (four gene-copies of BRP) impaired memory formation in young animals. Thus, in the Drosophila nervous system, aging AZs seem to steer towards the upper limit of their operational range, limiting synaptic plasticity and contributing to impairment of memory formation. Spermidine feeding suppresses age-dependent memory impairment by counteracting these age-dependent changes directly at the synapse.
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Affiliation(s)
- Varun K. Gupta
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Ulrike Pech
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Anuradha Bhukel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Andreas Fulterer
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Anatoli Ender
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Stephan F. Mauermann
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | | | | | - Christine Beuschel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Kerstin Thriene
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Christine Quentin
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - René Bushow
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Martin Schwärzel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Frank Madeo
- Institute for Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Joern Dengjel
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - André Fiala
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
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39
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Structural basis for tRNA modification by Elp3 from Dehalococcoides mccartyi. Nat Struct Mol Biol 2016; 23:794-802. [PMID: 27455459 PMCID: PMC5018218 DOI: 10.1038/nsmb.3265] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 06/17/2016] [Indexed: 12/11/2022]
Abstract
During translation elongation decoding is based on the recognition of codons by corresponding tRNA anticodon triplets. Molecular mechanisms that regulate global protein synthesis via specific base modifications in tRNA anticodons have recently received increasing attention. The conserved eukaryotic Elongator complex specifically modifies uridines located in the wobble base position of tRNAs. Here, we present the crystal structure of Dehalococcoides mccartyi Elp3 (DmcElp3) at 2.15 Å resolution. Our results reveal the unexpected arrangement of Elp3 lysine acetyl transferase (KAT) and radical S-adenosyl-methionine (SAM) domains that share a large interface to form a composite active site and tRNA binding pocket with an iron sulfur cluster located in the dimerization interface of two DmcElp3 molecules. Structure-guided mutagenesis studies of yeast Elp3 confirm the relevance of our findings for eukaryotic Elp3s and for understanding Elongator’s role in the onset of various neurodegenerative diseases and cancer in humans.
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40
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Woloszynska M, Le Gall S, Van Lijsebettens M. Plant Elongator-mediated transcriptional control in a chromatin and epigenetic context. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1025-33. [PMID: 27354117 DOI: 10.1016/j.bbagrm.2016.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/16/2016] [Accepted: 06/20/2016] [Indexed: 12/19/2022]
Abstract
Elongator (Elp) genes were identified in plants by the leaf growth-altering elo mutations in the yeast (Saccharomyces cerevisiae) gene homologs. Protein purification of the Elongator complex from Arabidopsis thaliana cell cultures confirmed its conserved structure and composition. The Elongator function in plant growth, development, and immune response is well-documented in the elp/elo mutants and correlated with the histone acetyl transferase activity of the ELP3/ELO3 subunit at the coding part of key regulatory genes of developmental and immune response pathways. Here we will focus on additional roles in transcription, such as the cytosine demethylation activity of ELP3/ELO3 at gene promoter regions and primary microRNA transcription and processing through the ELP2 subunit interaction with components of the small interference RNA machinery. Furthermore, specific interactions and upstream regulators support a role for Elongator in transcription and might reveal mechanistic insights into the specificity of the histone acetyl transferase and cytosine demethylation activities for target genes.
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Affiliation(s)
- Magdalena Woloszynska
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Sabine Le Gall
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Mieke Van Lijsebettens
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium.
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41
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Yang X, Li J, Zeng W, Li C, Mao B. Elongator Protein 3 (Elp3) stabilizes Snail1 and regulates neural crest migration in Xenopus. Sci Rep 2016; 6:26238. [PMID: 27189455 PMCID: PMC4870573 DOI: 10.1038/srep26238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/28/2016] [Indexed: 12/04/2022] Open
Abstract
Elongator protein 3 (Elp3) is the enzymatic unit of the elongator protein complex, a histone acetyltransferase complex involved in transcriptional elongation. It has long been shown to play an important role in cell migration; however, the underlying mechanism is unknown. Here, we showed that Elp3 is expressed in pre-migratory and migrating neural crest cells in Xenopus embryos, and knockdown of Elp3 inhibited neural crest cell migration. Interestingly, Elp3 binds Snail1 through its zinc-finger domain and inhibits its ubiquitination by β-Trcp without interfering with the Snail1/Trcp interaction. We showed evidence that Elp3-mediated stabilization of Snail1 was likely involved in the activation of N-cadherin in neural crest cells to regulate their migratory ability. Our findings provide a new mechanism for the function of Elp3 in cell migration through stabilizing Snail1, a master regulator of cell motility.
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Affiliation(s)
- Xiangcai Yang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650203, China
| | - Jiejing Li
- Center of Molecular Diagnostics, The Affiliated Hospital of KMUST, Medical School, Kunming University of Science and Technology, Kunming 650032, China
| | - Wanli Zeng
- China Tobacco Yunnan Industrial Co., Ltd., Kunming, 650024, China
| | - Chaocui Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
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42
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Abstract
Radical S-adenosylmethionine (SAM) enzymes catalyze an astonishing array of complex and chemically challenging reactions across all domains of life. Of approximately 114,000 of these enzymes, 8 are known to be present in humans: MOCS1, molybdenum cofactor biosynthesis; LIAS, lipoic acid biosynthesis; CDK5RAP1, 2-methylthio-N(6)-isopentenyladenosine biosynthesis; CDKAL1, methylthio-N(6)-threonylcarbamoyladenosine biosynthesis; TYW1, wybutosine biosynthesis; ELP3, 5-methoxycarbonylmethyl uridine; and RSAD1 and viperin, both of unknown function. Aberrations in the genes encoding these proteins result in a variety of diseases. In this review, we summarize the biochemical characterization of these 8 radical S-adenosylmethionine enzymes and, in the context of human health, describe the deleterious effects that result from such genetic mutations.
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Affiliation(s)
- Bradley J Landgraf
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Erin L McCarthy
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Squire J Booker
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802.,The Howard Hughes Medical Institute, The Pennsylvania State University, University Park, Pennsylvania 16802;
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Kittel RJ, Heckmann M. Synaptic Vesicle Proteins and Active Zone Plasticity. Front Synaptic Neurosci 2016; 8:8. [PMID: 27148040 PMCID: PMC4834300 DOI: 10.3389/fnsyn.2016.00008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/31/2016] [Indexed: 11/13/2022] Open
Abstract
Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of AZs vary significantly, even for a given connection. Thus, there appear to be distinct AZ states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the AZ. The protein-rich cytomatrix at the active zone (CAZ) provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1) and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and AZ states, which has heretofore received little attention.
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Affiliation(s)
- Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, Julius-Maximilians-University Würzburg Würzburg, Germany
| | - Manfred Heckmann
- Department of Neurophysiology, Institute of Physiology, Julius-Maximilians-University Würzburg Würzburg, Germany
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44
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Karlsborn T, Tükenmez H, Mahmud AKMF, Xu F, Xu H, Byström AS. Elongator, a conserved complex required for wobble uridine modifications in eukaryotes. RNA Biol 2015; 11:1519-28. [PMID: 25607684 DOI: 10.4161/15476286.2014.992276] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Elongator is a 6 subunit protein complex highly conserved in eukaryotes. The role of this complex has been controversial as the pleiotropic phenotypes of Elongator mutants have implicated the complex in several cellular processes. However, in yeast there is convincing evidence that the primary and probably only role of this complex is in formation of the 5-methoxycarbonylmethyl (mcm(5)) and 5-carbamoylmethyl (ncm(5)) side chains on uridines at wobble position in tRNA. In this review we summarize the cellular processes that have been linked to the Elongator complex and discuss its role in tRNA modification and regulation of translation. We also describe additional gene products essential for formation of ncm(5) and mcm(5) side chains at U34 and their influence on Elongator activity.
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Affiliation(s)
- Tony Karlsborn
- a Department of Molecular Biology ; Umeå University; Umeå , Sweden
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Woźnicka O, Görlich A, Sigrist S, Pyza E. BRP-170 and BRP190 isoforms of Bruchpilot protein differentially contribute to the frequency of synapses and synaptic circadian plasticity in the visual system of Drosophila. Front Cell Neurosci 2015; 9:238. [PMID: 26175667 PMCID: PMC4485229 DOI: 10.3389/fncel.2015.00238] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/12/2015] [Indexed: 11/13/2022] Open
Abstract
In the first optic neuropil (lamina) of the optic lobe of Drosophila melanogaster, two classes of synapses, tetrad and feedback, show daily rhythms in the number and size of presynaptic profiles examined at the level of transmission electron microscopy (TEM). Number of tetrad presynaptic profiles increases twice a day, once in the morning and again in the evening, and their presynaptic ribbons are largest in the evening. In contrast, feedback synapses peak at night. The frequency of synapses is correlated with size of the presynaptic element measured as the platform size of so-called T-bars, with T-bar platforms being largest with increasing synapse frequency. The large scaffold protein Bruchpilot (BRP) is a major essential constituent of T-bars, with two major isoforms of 190 and 170 kD forming T-bars of the peripheral neuromuscular junctions (NMJ) synapses and in the brain. In addition to the analysis of cyclic plasticity of tetrad and feedback synapses in wild-type flies, we used TEM to examine daily changes in the size and distribution of synapses within isoform-specific BRP mutants, expressing BRP-190 (BRPΔ170) or BRP-170 (BRPΔ190) only. We found that the number and circadian plasticity of synapses depends on both isoforms. In the BRPΔ190 lacking BRP-190 there was almost 50% less tetrad synapses demonstrable than when both isoforms were present. The lack of BRP-170 and BRP-190 increased and decreased, respectively the number of feedback synapses, indicating that BRP-190 forms most of the feedback synapses. In both mutants, the daily plasticity of tetrad and feedback presynaptic profiles was abolished, except for feedback synapses in BRPΔ190. The oscillations in the number and size of presynaptic elements seem to depend on a different contribution of BRP isoforms in a presynaptic element at different time during the day and night and at various synapse types. The participation of both BRP isoforms may vary in different classes of synapses.
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Affiliation(s)
- Olga Woźnicka
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
| | - Alicja Görlich
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
| | - Stephan Sigrist
- Neurogenetik, Institut für Biologie, Freie Universität Berlin Berlin, Germany ; NeuroCure and Institut für Medizinische Physik and Biophysik, Charité-Universitätsmedizin Berlin Berlin, Germany
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Krakow, Poland
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Azpurua J, Eaton BA. Neuronal epigenetics and the aging synapse. Front Cell Neurosci 2015; 9:208. [PMID: 26074775 PMCID: PMC4444820 DOI: 10.3389/fncel.2015.00208] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/13/2015] [Indexed: 11/13/2022] Open
Abstract
Two of the most salient phenotypes of aging are cognitive decline and loss of motor function, both of which are controlled by the nervous system. Cognition and muscle contraction require that neuronal synapses develop and maintain proper structure and function. We review the literature on how normal physiological aging disrupts central and peripheral synapse function including the degradation of structure and/or control of neurotransmission. Here we also attempt to connect the work done on the epigenetics of aging to the growing literature of how epigenetic mechanisms control synapse structure and function. Lastly, we address possible roles of epigenetic mechanisms to explain why the basal rates of age-related dysfunction vary so widely across individuals.
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Affiliation(s)
- Jorge Azpurua
- Department of Physiology, University of Texas Health Science Center at San Antonio San Antonio, TX, USA
| | - Benjamin A Eaton
- Department of Physiology, University of Texas Health Science Center at San Antonio San Antonio, TX, USA
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47
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The Elp2 subunit is essential for elongator complex assembly and functional regulation. Structure 2015; 23:1078-86. [PMID: 25960406 DOI: 10.1016/j.str.2015.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 03/20/2015] [Accepted: 03/25/2015] [Indexed: 01/24/2023]
Abstract
Elongator is a highly conserved multiprotein complex composed of six subunits (Elp1-6). Elongator has been associated with various cellular activities and has attracted clinical attention because of its role in certain neurodegenerative diseases. Here, we present the crystal structure of the Elp2 subunit revealing two seven-bladed WD40 β propellers, and show by structure-guided mutational analyses that the WD40 fold integrity of Elp2 is necessary for its binding to Elp1 and Elp3 subunits in multiple species. The detailed biochemical experiments indicate that Elp2 binds microtubules through its conserved alkaline residues in vitro and in vivo. We find that both the mutually independent Elp2-mediated Elongator assembly and the cytoskeleton association are important for yeast viability. In addition, mutation of Elp2 greatly affects the histone H3 acetylation activity of Elongator in vivo. Our results indicate that Elp2 is a necessary component for functional Elongator and acts as a hub in the formation of various complexes.
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Gaviño MA, Ford KJ, Archila S, Davis GW. Homeostatic synaptic depression is achieved through a regulated decrease in presynaptic calcium channel abundance. eLife 2015; 4. [PMID: 25884248 PMCID: PMC4443758 DOI: 10.7554/elife.05473] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 04/16/2015] [Indexed: 11/13/2022] Open
Abstract
Homeostatic signaling stabilizes synaptic transmission at the neuromuscular junction (NMJ) of Drosophila, mice, and human. It is believed that homeostatic signaling at the NMJ is bi-directional and considerable progress has been made identifying mechanisms underlying the homeostatic potentiation of neurotransmitter release. However, very little is understood mechanistically about the opposing process, homeostatic depression, and how bi-directional plasticity is achieved. Here, we show that homeostatic potentiation and depression can be simultaneously induced, demonstrating true bi-directional plasticity. Next, we show that mutations that block homeostatic potentiation do not alter homeostatic depression, demonstrating that these are genetically separable processes. Finally, we show that homeostatic depression is achieved by decreased presynaptic calcium channel abundance and calcium influx, changes that are independent of the presynaptic action potential waveform. Thus, we identify a novel mechanism of homeostatic synaptic plasticity and propose a model that can account for the observed bi-directional, homeostatic control of presynaptic neurotransmitter release.
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Affiliation(s)
- Michael A Gaviño
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Kevin J Ford
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Santiago Archila
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
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Müller M, Genç Ö, Davis GW. RIM-binding protein links synaptic homeostasis to the stabilization and replenishment of high release probability vesicles. Neuron 2015; 85:1056-69. [PMID: 25704950 DOI: 10.1016/j.neuron.2015.01.024] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 11/11/2014] [Accepted: 01/18/2015] [Indexed: 01/27/2023]
Abstract
Here we define activities of RIM-binding protein (RBP) that are essential for baseline neurotransmission and presynaptic homeostatic plasticity. At baseline, rbp mutants have a ∼10-fold decrease in the apparent Ca(2+) sensitivity of release that we attribute to (1) impaired presynaptic Ca(2+) influx, (2) looser coupling of vesicles to Ca(2+) influx, and (3) limited access to the readily releasable vesicle pool (RRP). During homeostatic plasticity, RBP is necessary for the potentiation of Ca(2+) influx and the expansion of the RRP. Remarkably, rbp mutants also reveal a rate-limiting stage required for the replenishment of high release probability (p) vesicles following vesicle depletion. This rate slows ∼4-fold at baseline and nearly 7-fold during homeostatic signaling in rbp. These effects are independent of altered Ca(2+) influx and RRP size. We propose that RBP stabilizes synaptic efficacy and homeostatic plasticity through coordinated control of presynaptic Ca(2+) influx and the dynamics of a high-p vesicle pool.
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Affiliation(s)
- Martin Müller
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Özgür Genç
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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50
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Abstract
![]()
Long
known for their role in histone acetylation, recent studies
have demonstrated that lysine acetyltransferases also carry out distinct
“orphan” functions. These activities impact a wide range
of biological phenomena including metabolism, RNA modification, nuclear
morphology, and mitochondrial function. Here, we review the discovery
and characterization of orphan lysine acetyltransferase functions.
In addition to highlighting the evidence and biological role for these
functions in human disease, we discuss the part emerging chemical
tools may play in investigating this versatile enzyme superfamily.
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Affiliation(s)
- David C. Montgomery
- National Cancer Institute, Chemical Biology Laboratory, Frederick, Maryland 21702-1201, United States
| | - Alexander W. Sorum
- National Cancer Institute, Chemical Biology Laboratory, Frederick, Maryland 21702-1201, United States
| | - Jordan L. Meier
- National Cancer Institute, Chemical Biology Laboratory, Frederick, Maryland 21702-1201, United States
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