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Birk MA, Liscovitch-Brauer N, Dominguez MJ, McNeme S, Yue Y, Hoff JD, Twersky I, Verhey KJ, Sutton RB, Eisenberg E, Rosenthal JJC. Temperature-dependent RNA editing in octopus extensively recodes the neural proteome. Cell 2023; 186:2544-2555.e13. [PMID: 37295402 PMCID: PMC10445230 DOI: 10.1016/j.cell.2023.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/24/2023] [Accepted: 05/04/2023] [Indexed: 06/12/2023]
Abstract
In poikilotherms, temperature changes challenge the integration of physiological function. Within the complex nervous systems of the behaviorally sophisticated coleoid cephalopods, these problems are substantial. RNA editing by adenosine deamination is a well-positioned mechanism for environmental acclimation. We report that the neural proteome of Octopus bimaculoides undergoes massive reconfigurations via RNA editing following a temperature challenge. Over 13,000 codons are affected, and many alter proteins that are vital for neural processes. For two highly temperature-sensitive examples, recoding tunes protein function. For synaptotagmin, a key component of Ca2+-dependent neurotransmitter release, crystal structures and supporting experiments show that editing alters Ca2+ binding. For kinesin-1, a motor protein driving axonal transport, editing regulates transport velocity down microtubules. Seasonal sampling of wild-caught specimens indicates that temperature-dependent editing occurs in the field as well. These data show that A-to-I editing tunes neurophysiological function in response to temperature in octopus and most likely other coleoids.
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Affiliation(s)
- Matthew A Birk
- Bell Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Biology, Saint Francis University, Loretto, PA 15940, USA
| | | | - Matthew J Dominguez
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79410, USA
| | - Sean McNeme
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Yang Yue
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - J Damon Hoff
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Itamar Twersky
- The Nano Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Kristen J Verhey
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - R Bryan Sutton
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79410, USA
| | - Eli Eisenberg
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel.
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Wang H, Duan W, Gao R, Li F, Yang L, Li W, Yin X, Wu S. Unique post-translational modifications diversify the sodium channels in peach aphid (Myzus persicae [Sulzer]). PEST MANAGEMENT SCIENCE 2021; 77:4521-4529. [PMID: 34041843 DOI: 10.1002/ps.6489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/19/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Myzus persicae (Sulzer), a worldwide pest, has caused remarkable damage to agriculture. Among the various control methods, chemical control (especially pyrethroids) is most commonly used. The targets of pyrethroids are voltage-gated sodium channels (Nav s). Unlike those of other insects, all Nav s of aphids (including two genes), such as Myzus persicae, are unique. RESULTS In this study, three interlock patterns, I(918)-F(1014), L(918)-L(1014), and T(918)-F(1014), were found at sites 918 and 1014 in the sensitive Myzus persicae strain. Similar to that of other aphids, the Nav of Myzus persicae (MpNav ) consisted of two parts, that is MpNav -I and MpNav -II, which were embedded with an atypical 'DENS' ion selectivity filter and a conventional 'MFM' inactivation gate, respectively. MpNav had 11 alternative exons, including two mutually exclusive exons (k and l) and three exons (w, x, and t), which were located in domains I and III, respectively. In addition, various RNA editing events, A503T and V588A, appearing between the connection of domains I and II and the S3 of domain IV, respectively, had been described. CONCLUSION Overall, MpNav was characterized by unique post-translational regulation mode, 918 and 1014 interlocks, and unusually alternative exons. Our research provides a new perspective on the evolution and variation of insect Nav s. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Hao Wang
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - WenBo Duan
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Ruibo Gao
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
| | - Fen Li
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
| | - Lei Yang
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
| | - WeiZheng Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - XinMing Yin
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - ShaoYing Wu
- Hainan University, The Innovation Team of Research, Development, and Application of Key Technologies for Safe Production of Tropical Crops, Haikou, China
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RNA editing is abundant and correlates with task performance in a social bumblebee. Nat Commun 2019; 10:1605. [PMID: 30962428 PMCID: PMC6453909 DOI: 10.1038/s41467-019-09543-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/15/2019] [Indexed: 12/17/2022] Open
Abstract
Colonies of the bumblebee Bombus terrestris are characterized by wide phenotypic variability among genetically similar full-sister workers, suggesting a major role for epigenetic processes. Here, we report a high level of ADAR-mediated RNA editing in the bumblebee, despite the lack of an ADAR1-homolog. We identify 1.15 million unique genomic sites, and 164 recoding sites residing in 100 protein coding genes, including ion channels, transporters, and receptors predicted to affect brain function and behavior. Some edited sites are similarly edited in other insects, cephalopods and even mammals. The global editing level of protein coding and non-coding transcripts weakly correlates with task performance (brood care vs. foraging), but not affected by dominance rank or juvenile hormone known to influence physiology and behavior. Taken together, our findings show that brain editing levels are high in naturally behaving bees, and may be regulated by relatively short-term effects associated with brood care or foraging activities.
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Abstract
AbstractVariability in the electrophysiological properties of homotypic photoreceptors is widespread and is thought to facilitate functioning under disparate illumination conditions. Compound eyes of insects have three sources of variability: inter-individual, intra-individual, and intra-ommatidial, the latter two overlapping. Here, I explored the causes of variability inPeriplaneta americana, a nocturnal insect characterized by highly variable photoreceptor responses. By recording from photoreceptors in dissociated ommatidia, including consecutive recordings from photoreceptors in the same ommatidium (SO), I studied the variability of six properties: whole-cell membrane capacitance (Cm), phototransduction latency, maximal conductance (Gmax) and the slope factor of the sustained Kv current, absolute sensitivity in dim light, and sustained light-induced current (LIC) amplitude in bright light. Coefficient of variation (CV) metrics were used to compare variances in four experimental groups: SO, same animal (SA), all data combined “full sample” (FS), and full sample of all SO recordings (FSSO). For the normally distributed parametersCm,Gmax, slope factor, and latency, the highest CV values were found in FS and FSSO, intermediate in SA, and the lowest in SO. On average, SO variance accounted for 47% of the full-sample variance in these four parameters. Absolute sensitivity and LIC values were not normally distributed, and the differences in variability between SO and FS/FSSO groups were smaller than for the other four parameters. These results indicate two main sources of variability, intra-ommatidial and inter-individual. Inter-individual variability was investigated by exposing adult cockroaches to constant light or dark for several months. In both groups, the majority of CV measures for the six parameters decreased compared to control, indicating substantial contribution of phenotypic plasticity to inter-individual differences. Analysis of variability of resting potential and elementary voltage responses revealed that resting potential is mainly determined by the sustained Kv conductance, whereas voltage bump amplitude is mainly determined by current bump amplitude andCm.
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Abstract
Adenosine-to-inosine (A-to-I) RNA editing is an important post-transcriptional modification that affects the information encoded from DNA to RNA to protein. RNA editing can generate a multitude of transcript isoforms and can potentially be used to optimize protein function in response to varying conditions. In light of this and the fact that millions of editing sites have been identified in many different species, it is interesting to examine the extent to which these sites have evolved to be functionally important. In this review, we discuss results pertaining to the evolution of RNA editing, specifically in humans, cephalopods, and Drosophila. We focus on how comparative genomics approaches have aided in the identification of sites that are likely to be advantageous. The use of RNA editing as a mechanism to adapt to varying environmental conditions will also be reviewed.
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Affiliation(s)
- Arielle L. Yablonovitch
- Stanford University, Department of Genetics, Stanford, California, United States of America
- Stanford University, Biophysics Program, Stanford, California, United States of America
| | - Patricia Deng
- Stanford University, Department of Genetics, Stanford, California, United States of America
| | - Dionna Jacobson
- Stanford University, Department of Genetics, Stanford, California, United States of America
| | - Jin Billy Li
- Stanford University, Department of Genetics, Stanford, California, United States of America
- * E-mail:
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Ruan H, Ueda A, Xing X, Wan X, Strub B, Mukai S, Certel K, Green D, Belozerov K, Yao WD, Johnson W, Jung-Ching Lin J, Hilliker AJ, Wu CF. Generation and characterization of new alleles of quiver (qvr) that encodes an extracellular modulator of the Shaker potassium channel. J Neurogenet 2017; 31:325-336. [PMID: 29117754 DOI: 10.1080/01677063.2017.1393076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Our earlier genetic screen uncovered a paraquat-sensitive leg-shaking mutant quiver1 (qvr1), whose gene product interacts with the Shaker (Sh) K+ channel. We also mapped the qvr locus to EY04063 and noticed altered day-night activity patterns in these mutants. Such circadian behavioral defects were independently reported by another group, who employed the qvr1 allele we supplied them, and attributed the extreme restless phenotype of EY04063 to the qvr gene. However, their report adopted a new noncanonical gene name sleepless (sss) for qvr. In addition to qvr1 and qvrEY, our continuous effort since the early 2000s generated a number of novel recessive qvr alleles, including ethyl methanesulfonate (EMS)-induced mutations qvr2 and qvr3, and P-element excision lines qvrip6 (imprecise jumpout), qvrrv7, and qvrrv9 (revertants) derived from qvrEY. Distinct from the original intron-located qvr1 allele that generates abnormal-sized mRNAs, qvr2, and qvr3 had their lesion sites in exons 6 and 7, respectively, producing nearly normal-sized mRNA products. A set of RNA-editing sites are nearby the lesion sites of qvr3 and qvrEY on exon 7. Except for the revertants, all qvr alleles display a clear ether-induced leg-shaking phenotype just like Sh, and weakened climbing abilities to varying degrees. Unlike Sh, all shaking qvr alleles (except for qvrf01257) displayed a unique activity-dependent enhancement in excitatory junction potentials (EJPs) at larval neuromuscular junctions (NMJs) at very low stimulus frequencies, with qvrEY displaying the largest EJP and more significant NMJ overgrowth than other alleles. Our detailed characterization of a collection of qvr alleles helps to establish links between novel molecular lesions and different behavioral and physiological consequences, revealing how modifications of the qvr gene lead to a wide spectrum of phenotypes, including neuromuscular hyperexcitability, defective motor ability and activity-rest cycles.
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Affiliation(s)
- Hongyu Ruan
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Atsushi Ueda
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Xiaomin Xing
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Xuxuan Wan
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Benjamin Strub
- b Department of Biology , York University , Toronto , ON , Canada
| | - Spencer Mukai
- b Department of Biology , York University , Toronto , ON , Canada
| | - Kaan Certel
- c Department of Molecular Physiology and Biophysics , University of Iowa , Iowa City , IA , USA
| | - David Green
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Kyle Belozerov
- b Department of Biology , York University , Toronto , ON , Canada
| | - Wei-Dong Yao
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Wayne Johnson
- c Department of Molecular Physiology and Biophysics , University of Iowa , Iowa City , IA , USA
| | | | | | - Chun-Fang Wu
- a Department of Biology , University of Iowa , Iowa City , IA , USA
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Zhao Y, Goldschen-Ohm MP, Morais-Cabral JH, Chanda B, Robertson GA. The intrinsically liganded cyclic nucleotide-binding homology domain promotes KCNH channel activation. J Gen Physiol 2017; 149:249-260. [PMID: 28122815 PMCID: PMC5299623 DOI: 10.1085/jgp.201611701] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/29/2016] [Accepted: 12/21/2016] [Indexed: 12/17/2022] Open
Abstract
hEAG1 is a member of the KCNH family of ion channels, which are characterized by C-terminal regions with homology to cyclic nucleotide–binding domains (CNBhDs). Zhao et al. show that an “intrinsic ligand” occupying the CNBhD binding pocket promotes the activated and open state of the channel. Channels in the ether-à-go-go or KCNH family of potassium channels are characterized by a conserved, C-terminal domain with homology to cyclic nucleotide–binding homology domains (CNBhDs). Instead of cyclic nucleotides, two amino acid residues, Y699 and L701, occupy the binding pocket, forming an “intrinsic ligand.” The role of the CNBhD in KCNH channel gating is still unclear, however, and a detailed characterization of the intrinsic ligand is lacking. In this study, we show that mutating both Y699 and L701 to alanine, serine, aspartate, or glycine impairs human EAG1 channel function. These mutants slow channel activation and shift the conductance–voltage (G–V) relation to more depolarized potentials. The mutations affect activation and the G-V relation progressively, indicating that the gating machinery is sensitive to multiple conformations of the CNBhD. Substitution with glycine at both sites (GG), which eliminates the side chains that interact with the binding pocket, also reduces the ability of voltage prepulses to populate more preactivated states along the activation pathway (i.e., the Cole–Moore effect), as if stabilizing the voltage sensor in deep resting states. Notably, deletion of the entire CNBhD (577–708, ΔCNBhD) phenocopies the GG mutant, suggesting that GG is a loss-of-function mutation and the CNBhD requires an intrinsic ligand to exert its functional effects. We developed a kinetic model for both wild-type and ΔCNBhD mutant channels that describes all our observations on activation kinetics, the Cole–Moore shift, and G-V relations. These findings support a model in which the CNBhD both promotes voltage sensor activation and stabilizes the open pore. The intrinsic ligand is critical for these functional effects.
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Affiliation(s)
- Yaxian Zhao
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705.,Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Marcel P Goldschen-Ohm
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705.,Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - João H Morais-Cabral
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4150 Porto, Portugal
| | - Baron Chanda
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705.,Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Gail A Robertson
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 .,Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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The Landscape of A-to-I RNA Editome Is Shaped by Both Positive and Purifying Selection. PLoS Genet 2016; 12:e1006191. [PMID: 27467689 PMCID: PMC4965139 DOI: 10.1371/journal.pgen.1006191] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 06/22/2016] [Indexed: 12/18/2022] Open
Abstract
The hydrolytic deamination of adenosine to inosine (A-to-I editing) in precursor mRNA induces variable gene products at the post-transcription level. How and to what extent A-to-I RNA editing diversifies transcriptome is not fully characterized in the evolution, and very little is known about the selective constraints that drive the evolution of RNA editing events. Here we present a study on A-to-I RNA editing, by generating a global profile of A-to-I editing for a phylogeny of seven Drosophila species, a model system spanning an evolutionary timeframe of approximately 45 million years. Of totally 9281 editing events identified, 5150 (55.5%) are located in the coding sequences (CDS) of 2734 genes. Phylogenetic analysis places these genes into 1,526 homologous families, about 5% of total gene families in the fly lineages. Based on conservation of the editing sites, the editing events in CDS are categorized into three distinct types, representing events on singleton genes (type I), and events not conserved (type II) or conserved (type III) within multi-gene families. While both type I and II events are subject to purifying selection, notably type III events are positively selected, and highly enriched in the components and functions of the nervous system. The tissue profiles are documented for three editing types, and their critical roles are further implicated by their shifting patterns during holometabolous development and in post-mating response. In conclusion, three A-to-I RNA editing types are found to have distinct evolutionary dynamics. It appears that nervous system functions are mainly tested to determine if an A-to-I editing is beneficial for an organism. The coding plasticity enabled by A-to-I editing creates a new class of binary variations, which is a superior alternative to maintain heterozygosity of expressed genes in a diploid mating system. One prevalent form of RNA editing is the deamination of adenosines (A-to-I editing) in the precursor mRNA molecules, pertaining to most organisms in the metazoan lineage. While examples of A-to-I editing on critical genes have been known for years, it has not been fully characterized how A-to-I editing shapes the transcriptome and proteome in the evolution. To understand how A-to-I editing affects genes’ evolution and how itself is constrained by selection, we generated a global profile of A-to-I editing for a phylogeny of seven fly species, a model system representing an evolutionary timeframe of about 45 million years. We are focused on 5150 editing sites (of totally 9281 identified) located in the coding region of 2734 genes. Our analysis revealed the evolution dynamics of A-to-I editing sites and functional specificity of targeted genes. The shifting patterns of A-to-I editing are documented during holometabolous development and in post-mating response in flies. This work points to the important roles of regulated RNA editing in animal development and offers new insight into the evolution of A-to-I editing events and their harboring genes.
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9
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Abstract
All true metazoans modify their RNAs by converting specific adenosine residues to inosine. Because inosine binds to cytosine, it is a biological mimic for guanosine. This subtle change, termed RNA editing, can have diverse effects on various RNA-mediated cellular pathways, including RNA interference, innate immunity, retrotransposon defense and messenger RNA recoding. Because RNA editing can be regulated, it is an ideal tool for increasing genetic diversity, adaptation and environmental acclimation. This review will cover the following themes related to RNA editing: (1) how it is used to modify different cellular RNAs, (2) how frequently it is used by different organisms to recode mRNA, (3) how specific recoding events regulate protein function, (4) how it is used in adaptation and (5) emerging evidence that it can be used for acclimation. Organismal biologists with an interest in adaptation and acclimation, but with little knowledge of RNA editing, are the intended audience.
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Affiliation(s)
- Joshua J C Rosenthal
- Universidad de Puerto Rico, Recinto de Ciencias Medicas, Instituto de Neurobiologia, 201 Blvd. del Valle, San Juan, PR 00901, USA
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Rieder LE, Savva YA, Reyna MA, Chang YJ, Dorsky JS, Rezaei A, Reenan RA. Dynamic response of RNA editing to temperature in Drosophila. BMC Biol 2015; 13:1. [PMID: 25555396 PMCID: PMC4299485 DOI: 10.1186/s12915-014-0111-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 12/22/2022] Open
Abstract
Background Adenosine-to-inosine RNA editing is a highly conserved process that post-transcriptionally modifies mRNA, generating proteomic diversity, particularly within the nervous system of metazoans. Transcripts encoding proteins involved in neurotransmission predominate as targets of such modifications. Previous reports suggest that RNA editing is responsive to environmental inputs in the form of temperature alterations. However, the molecular determinants underlying temperature-dependent RNA editing responses are not well understood. Results Using the poikilotherm Drosophila, we show that acute temperature alterations within a normal physiological range result in substantial changes in RNA editing levels. Our examination of particular sites reveals diversity in the patterns with which editing responds to temperature, and these patterns are conserved across five species of Drosophilidae representing over 10 million years of divergence. In addition, we show that expression of the editing enzyme, ADAR (adenosine deaminase acting on RNA), is dramatically decreased at elevated temperatures, partially, but not fully, explaining some target responses to temperature. Interestingly, this reduction in editing enzyme levels at elevated temperature is only partially reversed by a return to lower temperatures. Lastly, we show that engineered structural variants of the most temperature-sensitive editing site, in a sodium channel transcript, perturb thermal responsiveness in RNA editing profile for a particular RNA structure. Conclusions Our results suggest that the RNA editing process responds to temperature alterations via two distinct molecular mechanisms: through intrinsic thermo-sensitivity of the RNA structures that direct editing, and due to temperature sensitive expression or stability of the RNA editing enzyme. Environmental cues, in this case temperature, rapidly reprogram the Drosophila transcriptome through RNA editing, presumably resulting in altered proteomic ratios of edited and unedited proteins. Electronic supplementary material The online version of this article (doi:10.1186/s12915-014-0111-3) contains supplementary material, which is available to authorized users.
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Abstract
Potassium channels are pore-forming transmembrane proteins that regulate a multitude of biological processes by controlling potassium flow across cell membranes. Aberrant potassium channel functions contribute to diseases such as epilepsy, cardiac arrhythmia, and neuromuscular symptoms collectively known as channelopathies. Increasing evidence suggests that cancer constitutes another category of channelopathies associated with dysregulated channel expression. Indeed, potassium channel–modulating agents have demonstrated antitumor efficacy. Potassium channels regulate cancer cell behaviors such as proliferation and migration through both canonical ion permeation–dependent and noncanonical ion permeation–independent functions. Given their cell surface localization and well-known pharmacology, pharmacological strategies to target potassium channel could prove to be promising cancer therapeutics.
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Affiliation(s)
- Xi Huang
- Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Lily Yeh Jan
- Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
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12
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Abstract
Adenosine to inosine (A-to-I) RNA editing is a post-transcriptional process by which adenosines are selectively converted to inosines in double-stranded RNA (dsRNA) substrates. A highly conserved group of enzymes, the adenosine deaminase acting on RNA (ADAR) family, mediates this reaction. All ADARs share a common domain architecture consisting of a variable number of amino-terminal dsRNA binding domains (dsRBDs) and a carboxy-terminal catalytic deaminase domain. ADAR family members are highly expressed in the metazoan nervous system, where these enzymes predominantly localize to the neuronal nucleus. Once in the nucleus, ADARs participate in the modification of specific adenosines in pre-mRNAs of proteins involved in electrical and chemical neurotransmission, including pre-synaptic release machineries, and voltage- and ligand-gated ion channels. Most RNA editing sites in these nervous system targets result in non-synonymous codon changes in functionally important, usually conserved, residues and RNA editing deficiencies in various model organisms bear out a crucial role for ADARs in nervous system function. Mutation or deletion of ADAR genes results in striking phenotypes, including seizure episodes, extreme uncoordination, and neurodegeneration. Not only does the process of RNA editing alter important nervous system peptides, but ADARs also regulate gene expression through modification of dsRNA substrates that enter the RNA interference (RNAi) pathway and may then act at the chromatin level. Here, we present a review on the current knowledge regarding the ADAR protein family, including evolutionary history, key structural features, localization, function and mechanism.
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