1
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Sanchez-Martin V. Opportunities and challenges with G-quadruplexes as promising targets for drug design. Expert Opin Drug Discov 2024:1-15. [PMID: 39291583 DOI: 10.1080/17460441.2024.2404230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2024] [Accepted: 09/10/2024] [Indexed: 09/19/2024]
Abstract
INTRODUCTION G-quadruplexes (G4s) are secondary structures formed in guanine-rich regions of nucleic acids (both DNA and RNA). G4s are significantly enriched at regulatory genomic regions and are associated with important biological processes ranging from telomere homeostasis and genome instability to transcription and translation. Importantly, G4s are related to health and diseases such as cancer, neurological diseases, as well as infections with viruses and microbial pathogens. Increasing evidence suggests the potential of G4s for designing new diagnostic and therapeutic strategies although in vivo studies are still at early stages. AREAS COVERED This review provides an updated summary of the literature describing the impact of G4s in human diseases and different approaches based on G4 targeting in therapy. EXPERT OPINION Within the G4 field, most of the studies have been performed in vitro and in a descriptive manner. Therefore, detailed mechanistic understanding of G4s in the biological context remains to be deciphered. In clinics, the use of G4s as therapeutic targets has been hindered due to the low selectivity profile and poor drug-like properties of G4 ligands. Future research on G4s may overcome current methodological and interventional limitations and shed light on these unique structural elements in the pathogenesis and treatment of diseases.
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Affiliation(s)
- Victoria Sanchez-Martin
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Spanish National Research Council (CSIC), Seville, Spain
- Departament of Genetics, University of Seville, Seville, Spain
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2
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Sahoo BR, Kocman V, Clark N, Myers N, Deng X, Wong EL, Yang HJ, Kotar A, Guzman BB, Dominguez D, Plavec J, Bardwell JCA. Protein G-quadruplex interactions and their effects on phase transitions and protein aggregation. Nucleic Acids Res 2024; 52:4702-4722. [PMID: 38572746 PMCID: PMC11077067 DOI: 10.1093/nar/gkae229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/14/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024] Open
Abstract
The SERF family of proteins were originally discovered for their ability to accelerate amyloid formation. Znf706 is an uncharacterized protein whose N-terminus is homologous to SERF proteins. We show here that human Znf706 can promote protein aggregation and amyloid formation. Unexpectedly, Znf706 specifically interacts with stable, non-canonical nucleic acid structures known as G-quadruplexes. G-quadruplexes can affect gene regulation and suppress protein aggregation; however, it is unknown if and how these two activities are linked. We find Znf706 binds preferentially to parallel G-quadruplexes with low micromolar affinity, primarily using its N-terminus, and upon interaction, its dynamics are constrained. G-quadruplex binding suppresses Znf706's ability to promote protein aggregation. Znf706 in conjunction with G-quadruplexes therefore may play a role in regulating protein folding. RNAseq analysis shows that Znf706 depletion specifically impacts the mRNA abundance of genes that are predicted to contain high G-quadruplex density. Our studies give insight into how proteins and G-quadruplexes interact, and how these interactions affect both partners and lead to the modulation of protein aggregation and cellular mRNA levels. These observations suggest that the SERF family of proteins, in conjunction with G-quadruplexes, may have a broader role in regulating protein folding and gene expression than previously appreciated.
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Affiliation(s)
- Bikash R Sahoo
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Vojč Kocman
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Nathan Clark
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Nikhil Myers
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Xiexiong Deng
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ee L Wong
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Harry J Yang
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Anita Kotar
- National Institute of Chemistry, Ljubljana, Slovenia
| | | | | | - Janez Plavec
- National Institute of Chemistry, Ljubljana, Slovenia
| | - James C A Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Kallweit L, Hamlett ED, Saternos H, Gilmore A, Granholm AC, Horowitz S. A New Role for RNA G-quadruplexes in Aging and Alzheimer's Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.02.560545. [PMID: 37873355 PMCID: PMC10592952 DOI: 10.1101/2023.10.02.560545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
INTRODUCTION As the world population ages, new molecular targets in aging and Alzheimer's Disease (AD) are needed to combat the expected influx of new AD cases. Until now, the role of RNA structure in aging and neurodegeneration has largely remained unexplored. METHODS In this study, we examined human hippocampal postmortem tissue for the formation of RNA G-quadruplexes (rG4s) in aging and AD. RESULTS We found that rG4 immunostaining strongly increased in the hippocampus with both age and with AD severity. We further found that neurons with accumulation of phospho-tau immunostaining contained rG4s, that rG4 structure can drive tau aggregation, and that rG4 staining density depended on APOE genotype in the human tissue examined. DISCUSSION Combined with previous studies showing the dependence of rG4 structure on stress and the extreme power of rG4s at oligomerizing proteins, we propose a model of neurodegeneration in which chronic rG4 formation drives proteostasis collapse. We propose that further investigation of RNA structure in neurodegeneration is a critical avenue for future treatments and diagnoses.
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Affiliation(s)
- Lena Kallweit
- Department of Chemistry & Biochemistry and the Knoebel Institute for Healthy Aging, University of Denver, 2155 E Wesley Ave, Denver, CO 80208, USA
| | - Eric D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29425 USA
| | - Hannah Saternos
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, P15-5112, Aurora, CO 80045 USA
| | - Anah Gilmore
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, P15-5112, Aurora, CO 80045 USA
| | - Ann-Charlotte Granholm
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, 12700 East 19th Avenue, P15-5112, Aurora, CO 80045 USA
| | - Scott Horowitz
- Department of Chemistry & Biochemistry and the Knoebel Institute for Healthy Aging, University of Denver, 2155 E Wesley Ave, Denver, CO 80208, USA
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4
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Libonati L, Cambieri C, Colavito D, Moret F, D'Andrea E, Del Giudice E, Leon A, Inghilleri M, Ceccanti M. Genetics screening in an Italian cohort of patients with Amyotrophic Lateral Sclerosis: the importance of early testing and its implication. J Neurol 2024; 271:1921-1936. [PMID: 38112783 DOI: 10.1007/s00415-023-12142-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
INTRODUCTION Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease with an elusive etiology. While environmental factors have been considered, familial ALS cases have raised the possibility of genetic involvement. This genetic connection is increasingly evident, even in patients with sporadic ALS. We allowed access to the genetic test to all patients attending our clinic to identify the prevalence and the role of genetic variants in the development of the disease and to identify patients with potentially treatable forms of the disease. MATERIALS AND METHODS 194 patients with probable or definite ALS, were enrolled. A comprehensive genetic testing was performed, including sequencing all exons of the SOD1 gene and testing for hexanucleotide intronic repeat expansions (G4C2) in the C9orf72 gene using fluorescent repeat-primed PCR (RP-PCR). Whole Exome NGS Sequencing (WES) was performed, followed by an in silico multigene panel targeting neuromuscular diseases, spastic paraplegia, and motor distal neuropathies. We conducted statistical analyses to compare different patient groups. RESULTS Clinically significant pathogenetic variants were detected in 14.43% of cases. The highest prevalence of pathogenetic variants was observed in fALS patients, but a substantial proportion of sALS patients also displayed at least one variant, either pathogenetic or of uncertain significance (VUS). The most observed pathogenetic variant was the expansion of the C9orf72 gene, which was associated with a shorter survival. SOD1 variants were found in 1.6% of fALS and 2.5% of sALS patients. DISCUSSION The study reveals a significant number of ALS patients carrying pathogenic or likely pathogenic variants, with a higher prevalence in familial ALS cases. The expansion of the C9orf72 gene emerges as the most common genetic cause of ALS, affecting familial and sporadic cases. Additionally, SOD1 variants are detected at an unexpectedly higher rate, even in patients without a familial history of ALS, underscoring the crucial role of genetic testing in treatment decisions and potential participation in clinical trials. We also investigated variants in genes such as TARDBP, FUS, NEK1, TBK1, and DNAJC7, shedding light on their potential involvement in ALS. These findings underscore the complexity of interpreting variants of uncertain significance (VUS) and their ethical implications in patient communication and genetic counseling for patients' relatives. CONCLUSION This study emphasizes the diverse genetic basis of ALS and advocates for integrating comprehensive genetic testing into diagnostic protocols. The evolving landscape of genetic therapies requires identifying all eligible patients transcending traditional familial boundaries. The presence of VUS highlights the multifaceted nature of ALS genetics, prompting further exploration of complex interactions among genetic variants, environmental factors, and disease development.
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Affiliation(s)
- Laura Libonati
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy.
| | - Chiara Cambieri
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy
| | - Davide Colavito
- R & I Genetics, C.So Stati Uniti 4int.F, 35127, Padua, Italy
| | - Federica Moret
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy
| | - Edoardo D'Andrea
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy
| | | | - Alberta Leon
- R & I Genetics, C.So Stati Uniti 4int.F, 35127, Padua, Italy
| | - Maurizio Inghilleri
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy
| | - Marco Ceccanti
- Department of Human Neurosciences, Rare Neuromuscular Diseases Centre, Sapienza University, Viale Dell'Università 30, 00185, Rome, Italy
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5
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Luige J, Armaos A, Tartaglia GG, Ørom UAV. Predicting nuclear G-quadruplex RNA-binding proteins with roles in transcription and phase separation. Nat Commun 2024; 15:2585. [PMID: 38519458 PMCID: PMC10959947 DOI: 10.1038/s41467-024-46731-9] [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: 04/06/2023] [Accepted: 03/08/2024] [Indexed: 03/25/2024] Open
Abstract
RNA-binding proteins are central for many biological processes and their characterization has demonstrated a broad range of functions as well as a wide spectrum of target structures. RNA G-quadruplexes are important regulatory elements occurring in both coding and non-coding transcripts, yet our knowledge of their structure-based interactions is at present limited. Here, using theoretical predictions and experimental approaches, we show that many chromatin-binding proteins bind to RNA G-quadruplexes, and we classify them based on their RNA G-quadruplex-binding potential. Combining experimental identification of nuclear RNA G-quadruplex-binding proteins with computational approaches, we build a prediction tool that assigns probability score for a nuclear protein to bind RNA G-quadruplexes. We show that predicted G-quadruplex RNA-binding proteins exhibit a high degree of protein disorder and hydrophilicity and suggest involvement in both transcription and phase-separation into membrane-less organelles. Finally, we present the G4-Folded/UNfolded Nuclear Interaction Explorer System (G4-FUNNIES) for estimating RNA G4-binding propensities at http://service.tartaglialab.com/new_submission/G4FUNNIES .
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Affiliation(s)
- Johanna Luige
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alexandros Armaos
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), Via Enrico Melen, 83, 16152, Genova, Italy
| | - Gian Gaetano Tartaglia
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), Via Enrico Melen, 83, 16152, Genova, Italy.
- Catalan Institution for Research and Advanced Studies ICREA Passeig Lluis Companys, 23 08010, Barcelona, Spain.
| | - Ulf Andersson Vang Ørom
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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6
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Sahoo BR, Kocman V, Clark N, Myers N, Deng X, Wong EL, Yang HJ, Kotar A, Guzman BB, Dominguez D, Plavec J, Bardwell JC. Protein G-quadruplex interactions and their effects on phase transitions and protein aggregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.21.558871. [PMID: 37790366 PMCID: PMC10542165 DOI: 10.1101/2023.09.21.558871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The SERF family of proteins were originally discovered for their ability to accelerate amyloid formation. Znf706 is an uncharacterized protein whose N-terminus is homologous to SERF proteins. We show here that human Znf706 can promote protein aggregation and amyloid formation. Unexpectedly, Znf706 specifically interacts with stable, non-canonical nucleic acid structures known as G-quadruplexes. G-quadruplexes can affect gene regulation and suppress protein aggregation; however, it is unknown if and how these two activities are linked. We find Znf706 binds preferentially to parallel G-quadruplexes with low micromolar affinity, primarily using its N-terminus, and upon interaction, its dynamics are constrained. G-quadruplex binding suppresses Znf706's ability to promote protein aggregation. Znf706 in conjunction with G-quadruplexes therefore may play a role in regulating protein folding. RNAseq analysis shows that Znf706 depletion specifically impacts the mRNA abundance of genes that are predicted to contain high G-quadruplex density. Our studies give insight into how proteins and G-quadruplexes interact, and how these interactions affect both partners and lead to the modulation of protein aggregation and cellular mRNA levels. These observations suggest that the SERF family of proteins, in conjunction with G-quadruplexes, may have a broader role in regulating protein folding and gene expression than previously appreciated.
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Affiliation(s)
- Bikash R. Sahoo
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Vojč Kocman
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Nathan Clark
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Nikhil Myers
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Xiexiong Deng
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ee L. Wong
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Harry J. Yang
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Anita Kotar
- National Institute of Chemistry, Ljubljana, Slovenia
| | | | | | - Janez Plavec
- National Institute of Chemistry, Ljubljana, Slovenia
| | - James C.A. Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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7
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Fakim H, Vande Velde C. The implications of physiological biomolecular condensates in amyotrophic lateral sclerosis. Semin Cell Dev Biol 2024; 156:176-189. [PMID: 37268555 DOI: 10.1016/j.semcdb.2023.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 06/04/2023]
Abstract
In recent years, there has been an emphasis on the role of phase-separated biomolecular condensates, especially stress granules, in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). This is largely due to several ALS-associated mutations occurring in genes involved in stress granule assembly and observations that pathological inclusions detected in ALS patient neurons contain stress granule proteins, including the ALS-linked proteins TDP-43 and FUS. However, protein components of stress granules are also found in numerous other phase-separated biomolecular condensates under physiological conditions which are inadequately discussed in the context of ALS. In this review, we look beyond stress granules and describe the roles of TDP-43 and FUS in physiological condensates occurring in the nucleus and neurites, such as the nucleolus, Cajal bodies, paraspeckles and neuronal RNA transport granules. We also discuss the consequences of ALS-linked mutations in TDP-43 and FUS on their ability to phase separate into these stress-independent biomolecular condensates and perform their respective functions. Importantly, biomolecular condensates sequester multiple overlapping protein and RNA components, and their dysregulation could contribute to the observed pleiotropic effects of both sporadic and familial ALS on RNA metabolism.
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Affiliation(s)
- Hana Fakim
- Department of Neurosciences, Université de Montréal, and CHUM Research Center, Montréal, QC, Canada
| | - Christine Vande Velde
- Department of Neurosciences, Université de Montréal, and CHUM Research Center, Montréal, QC, Canada.
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8
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Yu X, Tang L, Tang X, Mao Y. Genome-Wide Identification and Analysis of MYB Transcription Factors in Pyropia yezoensis. PLANTS (BASEL, SWITZERLAND) 2023; 12:3613. [PMID: 37896076 PMCID: PMC10609806 DOI: 10.3390/plants12203613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023]
Abstract
MYB transcription factors are one of the largest transcription factor families in plants, and they regulate numerous biological processes. Red algae are an important taxonomic group and have important roles in economics and research. However, no comprehensive analysis of the MYB gene family in any red algae, including Pyropia yezoensis, has been conducted. To identify the MYB gene members of Py. yezoensis, and to investigate their family structural features and expression profile characteristics, a study was conducted. In this study, 3 R2R3-MYBs and 13 MYB-related members were identified in Py. yezoensis. Phylogenetic analysis indicated that most red algae MYB genes could be clustered with green plants or Glaucophyta MYB genes, inferring their ancient origins. Synteny analysis indicated that 13 and 5 PyMYB genes were orthologous to Pyropia haitanensis and Porphyra umbilicalis, respectively. Most Bangiaceae MYB genes contain several Gly-rich motifs, which may be the result of an adaptation to carbon limitations and maintenance of important regulatory functions. An expression profile analysis showed that PyMYB genes exhibited diverse expression profiles. However, the expression patterns of different members appeared to be diverse, and PyMYB5 was upregulated in response to dehydration, low temperature, and Pythium porphyrae infection. This is the first comprehensive study of the MYB gene family in Py. Yezoensis and it provides vital insights into the functional divergence of MYB genes.
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Affiliation(s)
- Xinzi Yu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Lei Tang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Xianghai Tang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Yunxiang Mao
- MOE Key Laboratory of Utilization and Conservation of Tropical Marine Bioresource & Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
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9
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Guzman BB, Son A, Litberg TJ, Huang Z, Dominguez D, Horowitz S. Emerging roles for G-quadruplexes in proteostasis. FEBS J 2023; 290:4614-4625. [PMID: 36017725 PMCID: PMC10071977 DOI: 10.1111/febs.16608] [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: 04/05/2022] [Revised: 07/22/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
Abstract
How nucleic acids interact with proteins, and how they affect protein folding, aggregation, and misfolding is a still-evolving area of research. Considerable effort is now focusing on a particular structure of RNA and DNA, G-quadruplexes, and their role in protein homeostasis and disease. In this state-of-the-art review, we track recent reports on how G-quadruplexes influence protein aggregation, proteolysis, phase separation, and protein misfolding diseases, and pose currently unanswered questions in the advance of this scientific field.
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Affiliation(s)
- Bryan B Guzman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ahyun Son
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA
| | - Theodore J Litberg
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA
| | - Zijue Huang
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA
| | - Daniel Dominguez
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Scott Horowitz
- Department of Chemistry & Biochemistry, Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA
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10
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Ishiguro A, Ishihama A. ALS-linked TDP-43 mutations interfere with the recruitment of RNA recognition motifs to G-quadruplex RNA. Sci Rep 2023; 13:5982. [PMID: 37046025 PMCID: PMC10097714 DOI: 10.1038/s41598-023-33172-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/08/2023] [Indexed: 04/14/2023] Open
Abstract
TDP-43 is a major pathological protein in sporadic and familial amyotrophic lateral sclerosis (ALS) and mediates mRNA fate. TDP-43 dysfunction leads to causes progressive degeneration of motor neurons, the details of which remain elusive. Elucidation of the molecular mechanisms of RNA binding could enhance our understanding of this devastating disease. We observed the involvement of the glycine-rich (GR) region of TDP-43 in the initial recognition and binding of G-quadruplex (G4)-RNA in conjunction with its RNA recognition motifs (RRM). We performed a molecular dissection of these intramolecular RNA-binding modules in this study. We confirmed that the ALS-linked mutations in the GR region lead to alteration in the G4 structure. In contrast, amino acid substitutions in the GR region alter the protein structure but do not void the interaction with G4-RNA. Based on these observations, we concluded that the structural distortion of G4 caused by these mutations interferes with RRM recruitment and leads to TDP-43 dysfunction. This intramolecular organization between RRM and GR regions modulates the overall G4-binding properties.
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Affiliation(s)
- Akira Ishiguro
- Research Center for Micro-Nano Technology, Hosei University, Midori-cho 3-11-15, Koganei, Tokyo, 184-0003, Japan.
| | - Akira Ishihama
- Research Center for Micro-Nano Technology, Hosei University, Midori-cho 3-11-15, Koganei, Tokyo, 184-0003, Japan
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11
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An atypical RNA quadruplex marks RNAs as vectors for gene silencing. Nat Struct Mol Biol 2022; 29:1113-1121. [PMID: 36352138 PMCID: PMC10092862 DOI: 10.1038/s41594-022-00854-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
The addition of poly(UG) ('pUG') repeats to 3' termini of mRNAs drives gene silencing and transgenerational epigenetic inheritance in the metazoan Caenorhabditis elegans. pUG tails promote silencing by recruiting an RNA-dependent RNA polymerase (RdRP) that synthesizes small interfering RNAs. Here we show that active pUG tails require a minimum of 11.5 repeats and adopt a quadruplex (G4) structure we term the pUG fold. The pUG fold differs from known G4s in that it has a left-handed backbone similar to Z-RNA, no consecutive guanosines in its sequence, and three G quartets and one U quartet stacked non-sequentially. The compact pUG fold binds six potassium ions and brings the RNA ends into close proximity. The biological importance of the pUG fold is emphasized by our observations that porphyrin molecules bind to the pUG fold and inhibit both gene silencing and binding of RdRP. Moreover, specific 7-deaza substitutions that disrupt the pUG fold neither bind RdRP nor induce RNA silencing. These data define the pUG fold as a previously unrecognized RNA structural motif that drives gene silencing. The pUG fold can also form internally within larger RNA molecules. Approximately 20,000 pUG-fold sequences are found in noncoding regions of human RNAs, suggesting that the fold probably has biological roles beyond gene silencing.
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12
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Ishiguro A, Ishihama A. Essential Roles and Risks of G-Quadruplex Regulation: Recognition Targets of ALS-Linked TDP-43 and FUS. Front Mol Biosci 2022; 9:957502. [PMID: 35898304 PMCID: PMC9309350 DOI: 10.3389/fmolb.2022.957502] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/21/2022] [Indexed: 11/26/2022] Open
Abstract
A non-canonical DNA/RNA structure, G-quadruplex (G4), is a unique structure formed by two or more guanine quartets, which associate through Hoogsteen hydrogen bonding leading to form a square planar arrangement. A set of RNA-binding proteins specifically recognize G4 structures and play certain unique physiological roles. These G4-binding proteins form ribonucleoprotein (RNP) through a physicochemical phenomenon called liquid-liquid phase separation (LLPS). G4-containing RNP granules are identified in both prokaryotes and eukaryotes, but extensive studies have been performed in eukaryotes. We have been involved in analyses of the roles of G4-containing RNAs recognized by two G4-RNA-binding proteins, TDP-43 and FUS, which both are the amyotrophic lateral sclerosis (ALS) causative gene products. These RNA-binding proteins play the essential roles in both G4 recognition and LLPS, but they also carry the risk of agglutination. The biological significance of G4-binding proteins is controlled through unique 3D structure of G4, of which the risk of conformational stability is influenced by environmental conditions such as monovalent metals and guanine oxidation.
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13
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Ojaimi YA, Dangoumau A, Alarcan H, Hergesheimer R, Vourc'h P, Corcia P, Lanznaster D, Blasco H. TAR DNA-binding protein of 43 kDa (TDP-43) and amyotrophic lateral sclerosis (ALS): a promising therapeutic target. Expert Opin Ther Targets 2022; 26:575-592. [PMID: 35652285 DOI: 10.1080/14728222.2022.2083958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that lacks an effective treatment. Aggregates of the TAR DNA-binding protein-43 (TDP-43) are observed in 97% of all ALS cases, thus making this protein a major therapeutic target in ALS. . AREAS COVERED The authors describe the major cellular functions of TDP-43 and the features and consequences of TDP-43 proteinopathy. Drawing from fundamental and preclinical studies on cellular and animal TDP-43 models of ALS and selected clinical trials, the major pathways that have been targeted for the mitigation of TDP-43 pathology in ALS are discussed. The authors provide insights on the approaches targeting the tendency of TDP-43 for aggregation, defective nucleocytoplasmic transport, dysfunctional proteostasis, abnormal stress granule dynamics, and pathological post-translational modifications of TDP-43. EXPERT OPINION The complexity of ALS and TDP-43 proteinopathy generates challenges for the development of novel therapeutic approaches. However, the critical involvement of TDP-43 in the initiation and progression of ALS, makes it a promising therapeutic target. Further research should be centered on the development of precision strategies, consideration of patient subgroups, the prevention of the mislocalization of TDP-43 and restoration of the lost functions of TPD-43. .
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Affiliation(s)
| | | | - Hugo Alarcan
- UMR 1253 iBrain, Université de Tours, Tours, France.,Laboratoire de biochimie et biologie moléculaire, CHRU Bretonneau, Tours, France
| | | | - Patrick Vourc'h
- UMR 1253 iBrain, Université de Tours, Tours, France.,Laboratoire de biochimie et biologie moléculaire, CHRU Bretonneau, Tours, France
| | - Philippe Corcia
- Laboratoire de biochimie et biologie moléculaire, CHRU Bretonneau, Tours, France.,Service de neurologie, CHRU Bretonneau, Tours, France
| | | | - Hélène Blasco
- UMR 1253 iBrain, Université de Tours, Tours, France.,Laboratoire de biochimie et biologie moléculaire, CHRU Bretonneau, Tours, France
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14
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Georgakopoulos-Soares I, Parada GE, Hemberg M. Secondary structures in RNA synthesis, splicing and translation. Comput Struct Biotechnol J 2022; 20:2871-2884. [PMID: 35765654 PMCID: PMC9198270 DOI: 10.1016/j.csbj.2022.05.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022] Open
Abstract
Even though the functional role of mRNA molecules is primarily decided by the nucleotide sequence, several properties are determined by secondary structure conformations. Examples of secondary structures include long range interactions, hairpins, R-loops and G-quadruplexes and they are formed through interactions of non-adjacent nucleotides. Here, we discuss advances in our understanding of how secondary structures can impact RNA synthesis, splicing, translation and mRNA half-life. During RNA synthesis, secondary structures determine RNA polymerase II (RNAPII) speed, thereby influencing splicing. Splicing is also determined by RNA binding proteins and their binding rates are modulated by secondary structures. For the initiation of translation, secondary structures can control the choice of translation start site. Here, we highlight the mechanisms by which secondary structures modulate these processes, discuss advances in technologies to detect and study them systematically, and consider the roles of RNA secondary structures in disease.
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Affiliation(s)
- Ilias Georgakopoulos-Soares
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Guillermo E. Parada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5A 1A8, Canada
| | - Martin Hemberg
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston, MA, USA
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15
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Ishiguro A, Lu J, Ozawa D, Nagai Y, Ishihama A. ALS-linked FUS mutations dysregulate G-quadruplex-dependent liquid-liquid phase separation and liquid-to-solid transition. J Biol Chem 2021; 297:101284. [PMID: 34624313 PMCID: PMC8567205 DOI: 10.1016/j.jbc.2021.101284] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 01/15/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the accumulation of protein aggregates in motor neurons. Recent discoveries of genetic mutations in ALS patients promoted research into the complex molecular mechanisms underlying ALS. FUS (fused in sarcoma) is a representative ALS-linked RNA-binding protein (RBP) that specifically recognizes G-quadruplex (G4)-DNA/RNAs. However, the effects of ALS-linked FUS mutations on the G4-RNA-binding activity and the phase behavior have never been investigated. Using the purified full-length FUS, we analyzed the molecular mechanisms of multidomain structures consisting of multiple functional modules that bind to G4. Here we succeeded to observe the liquid–liquid phase separation (LLPS) of FUS condensate formation and subsequent liquid-to-solid transition (LST) leading to the formation of FUS aggregates. This process was markedly promoted through FUS interaction with G4-RNA. To further investigate, we selected a total of eight representative ALS-linked FUS mutants within multidomain structures and purified these proteins. The regulation of G4-RNA-dependent LLPS and LST pathways was lost for all ALS-linked FUS mutants defective in G4-RNA recognition tested, supporting the essential role of G4-RNA in this process. Noteworthy, the P525L mutation that causes juvenile ALS exhibited the largest effect on both G4-RNA binding and FUS aggregation. The findings described herein could provide a clue to the hitherto undefined connection between protein aggregation and dysfunction of RBPs in the complex pathway of ALS pathogenesis.
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Affiliation(s)
- Akira Ishiguro
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan.
| | - Jun Lu
- Medical Examination Center, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Daisaku Ozawa
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Osaka, Japan
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Neurology, Kindai University Faculty of Medicine, Osaka-Sayama, Osaka, Japan
| | - Akira Ishihama
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
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16
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Wang E, Thombre R, Shah Y, Latanich R, Wang J. G-Quadruplexes as pathogenic drivers in neurodegenerative disorders. Nucleic Acids Res 2021; 49:4816-4830. [PMID: 33784396 PMCID: PMC8136783 DOI: 10.1093/nar/gkab164] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 02/20/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
G-quadruplexes (G4s), higher-order DNA and RNA secondary structures featuring guanine-rich nucleic acid sequences with various conformations, are widely distributed in the human genome. These structural motifs are known to participate in basic cellular processes, including transcription, splicing, and translation, and their functions related to health and disease are becoming increasingly recognized. In this review, we summarize the landscape of G4s involved in major neurodegenerative disorders, describing the genes that contain G4-forming sequences and proteins that have high affinity for G4-containing elements. The functions of G4s are diverse, with potentially protective or deleterious effects in the pathogenic cascades of various neurological diseases. While the studies of the functions of G4s in vivo, including those involved in pathophysiology, are still in their early stages, we will nevertheless discuss the evidence pointing to their biological relevance. A better understanding of this unique structural element in the biological context is important for unveiling its potential roles in the pathogenesis of diseases such as neurodegeneration and for designing new diagnostic and therapeutic strategies.
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Affiliation(s)
- Ernest Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ravi Thombre
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yajas Shah
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Rachel Latanich
- Department of Medicine, Division of Gastroenterology and Hepatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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17
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Dettori LG, Torrejon D, Chakraborty A, Dutta A, Mohamed M, Papp C, Kuznetsov VA, Sung P, Feng W, Bah A. A Tale of Loops and Tails: The Role of Intrinsically Disordered Protein Regions in R-Loop Recognition and Phase Separation. Front Mol Biosci 2021; 8:691694. [PMID: 34179096 PMCID: PMC8222781 DOI: 10.3389/fmolb.2021.691694] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/14/2021] [Indexed: 11/13/2022] Open
Abstract
R-loops are non-canonical, three-stranded nucleic acid structures composed of a DNA:RNA hybrid, a displaced single-stranded (ss)DNA, and a trailing ssRNA overhang. R-loops perform critical biological functions under both normal and disease conditions. To elucidate their cellular functions, we need to understand the mechanisms underlying R-loop formation, recognition, signaling, and resolution. Previous high-throughput screens identified multiple proteins that bind R-loops, with many of these proteins containing folded nucleic acid processing and binding domains that prevent (e.g., topoisomerases), resolve (e.g., helicases, nucleases), or recognize (e.g., KH, RRMs) R-loops. However, a significant number of these R-loop interacting Enzyme and Reader proteins also contain long stretches of intrinsically disordered regions (IDRs). The precise molecular and structural mechanisms by which the folded domains and IDRs synergize to recognize and process R-loops or modulate R-loop-mediated signaling have not been fully explored. While studying one such modular R-loop Reader, the Fragile X Protein (FMRP), we unexpectedly discovered that the C-terminal IDR (C-IDR) of FMRP is the predominant R-loop binding site, with the three N-terminal KH domains recognizing the trailing ssRNA overhang. Interestingly, the C-IDR of FMRP has recently been shown to undergo spontaneous Liquid-Liquid Phase Separation (LLPS) assembly by itself or in complex with another non-canonical nucleic acid structure, RNA G-quadruplex. Furthermore, we have recently shown that FMRP can suppress persistent R-loops that form during transcription, a process that is also enhanced by LLPS via the assembly of membraneless transcription factories. These exciting findings prompted us to explore the role of IDRs in R-loop processing and signaling proteins through a comprehensive bioinformatics and computational biology study. Here, we evaluated IDR prevalence, sequence composition and LLPS propensity for the known R-loop interactome. We observed that, like FMRP, the majority of the R-loop interactome, especially Readers, contains long IDRs that are highly enriched in low complexity sequences with biased amino acid composition, suggesting that these IDRs could directly interact with R-loops, rather than being “mere flexible linkers” connecting the “functional folded enzyme or binding domains”. Furthermore, our analysis shows that several proteins in the R-loop interactome are either predicted to or have been experimentally demonstrated to undergo LLPS or are known to be associated with phase separated membraneless organelles. Thus, our overall results present a thought-provoking hypothesis that IDRs in the R-loop interactome can provide a functional link between R-loop recognition via direct binding and downstream signaling through the assembly of LLPS-mediated membrane-less R-loop foci. The absence or dysregulation of the function of IDR-enriched R-loop interactors can potentially lead to severe genomic defects, such as the widespread R-loop-mediated DNA double strand breaks that we recently observed in Fragile X patient-derived cells.
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Affiliation(s)
- Leonardo G Dettori
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Diego Torrejon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mohamed Mohamed
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Csaba Papp
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Urology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Vladimir A Kuznetsov
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, United States.,Bioinformatics Institute, ASTAR Biomedical Institutes, Singapore, Singapore
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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18
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Wood A, Gurfinkel Y, Polain N, Lamont W, Lyn Rea S. Molecular Mechanisms Underlying TDP-43 Pathology in Cellular and Animal Models of ALS and FTLD. Int J Mol Sci 2021; 22:4705. [PMID: 33946763 PMCID: PMC8125728 DOI: 10.3390/ijms22094705] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 02/03/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are neurodegenerative disorders that exist on a disease spectrum due to pathological, clinical and genetic overlap. In up to 97% of ALS cases and ~50% of FTLD cases, the primary pathological protein observed in affected tissues is TDP-43, which is hyperphosphorylated, ubiquitinated and cleaved. The TDP-43 is observed in aggregates that are abnormally located in the cytoplasm. The pathogenicity of TDP-43 cytoplasmic aggregates may be linked with both a loss of nuclear function and a gain of toxic functions. The cellular processes involved in ALS and FTLD disease pathogenesis include changes to RNA splicing, abnormal stress granules, mitochondrial dysfunction, impairments to axonal transport and autophagy, abnormal neuromuscular junctions, endoplasmic reticulum stress and the subsequent induction of the unfolded protein response. Here, we review and discuss the evidence for alterations to these processes that have been reported in cellular and animal models of TDP-43 proteinopathy.
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Affiliation(s)
- Alistair Wood
- School of Molecular Science, University of Western Australia, Nedlands 6009, Australia;
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
| | - Yuval Gurfinkel
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands 6009, Australia;
| | - Nicole Polain
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
| | - Wesley Lamont
- Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands 6009, Australia;
| | - Sarah Lyn Rea
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Health Research Building, Discovery Way, Murdoch 6150, Australia; (Y.G.); (N.P.)
- Hub for Immersive Visualisation and eResearch, Curtin University, Bentley 6102, Australia
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands 6009, Australia
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19
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Bartas M, Červeň J, Guziurová S, Slychko K, Pečinka P. Amino Acid Composition in Various Types of Nucleic Acid-Binding Proteins. Int J Mol Sci 2021; 22:ijms22020922. [PMID: 33477647 PMCID: PMC7831508 DOI: 10.3390/ijms22020922] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 12/20/2022] Open
Abstract
Nucleic acid-binding proteins are traditionally divided into two categories: With the ability to bind DNA or RNA. In the light of new knowledge, such categorizing should be overcome because a large proportion of proteins can bind both DNA and RNA. Another even more important features of nucleic acid-binding proteins are so-called sequence or structure specificities. Proteins able to bind nucleic acids in a sequence-specific manner usually contain one or more of the well-defined structural motifs (zinc-fingers, leucine zipper, helix-turn-helix, or helix-loop-helix). In contrast, many proteins do not recognize nucleic acid sequence but rather local DNA or RNA structures (G-quadruplexes, i-motifs, triplexes, cruciforms, left-handed DNA/RNA form, and others). Finally, there are also proteins recognizing both sequence and local structural properties of nucleic acids (e.g., famous tumor suppressor p53). In this mini-review, we aim to summarize current knowledge about the amino acid composition of various types of nucleic acid-binding proteins with a special focus on significant enrichment and/or depletion in each category.
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20
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Ishiguro A, Katayama A, Ishihama A. Different recognition modes of G-quadruplex RNA between two ALS/FTLD-linked proteins TDP-43 and FUS. FEBS Lett 2020; 595:310-323. [PMID: 33269497 DOI: 10.1002/1873-3468.14013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/15/2020] [Accepted: 11/25/2020] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis/frontotemporal lobar degeneration-linked proteins, TDP-43 and fused in sarcoma (FUS), bind to G-quadruplex-containing mRNAs and transport them to distal neurites for local translation. The specificity and mechanism of G4-RNA binding, however, remain largely unsolved. Using purified full-length TDP-43 and FUS and a set of seven G4-DNA/RNA, we compared their recognition properties of G4-RNAs. Both TDP-43 and FUS recognized and bound to G4-DNA/RNAs, but the target selectivity differed between two proteins. TDP-43 recognized only parallel-stranded G4-DNA/RNAs, leading to stabilize the G4 conformation. In contrast, FUS bound to all three types, parallel, hybrid, and antiparallel, of G4-DNA/RNAs, resulting in deformation of the G4 structure. We then concluded that the target selectivity and the influence on G4 RNA structure differed between TDP-43 and FUS.
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Affiliation(s)
- Akira Ishiguro
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Japan
| | - Akira Katayama
- Department of Molecular Analysis Laboratory, Nippon Medical School, Bunkyo-ku, Japan
| | - Akira Ishihama
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Japan
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21
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Suk TR, Rousseaux MWC. The role of TDP-43 mislocalization in amyotrophic lateral sclerosis. Mol Neurodegener 2020; 15:45. [PMID: 32799899 PMCID: PMC7429473 DOI: 10.1186/s13024-020-00397-1] [Citation(s) in RCA: 176] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023] Open
Abstract
Since its discovery as a primary component in cytoplasmic aggregates in post-mortem tissue of patients with Amyotrophic Lateral Sclerosis (ALS), TAR DNA Binding Protein 43 kDa (TDP-43) has remained a central focus to understand the disease. TDP-43 links both familial and sporadic forms of ALS as mutations are causative for disease and cytoplasmic aggregates are a hallmark of nearly all cases, regardless of TDP-43 mutational status. Research has focused on the formation and consequences of cytosolic protein aggregates as drivers of ALS pathology through both gain- and loss-of-function mechanisms. Not only does aggregation sequester the normal function of TDP-43, but these aggregates also actively block normal cellular processes inevitably leading to cellular demise in a short time span. Although there may be some benefit to therapeutically targeting TDP-43 aggregation, this step may be too late in disease development to have substantial therapeutic benefit. However, TDP-43 pathology appears to be tightly linked with its mislocalization from the nucleus to the cytoplasm, making it difficult to decouple the consequences of nuclear-to-cytoplasmic mislocalization from protein aggregation. Studies focusing on the effects of TDP-43 mislocalization have demonstrated both gain- and loss-of-function consequences including altered splicing regulation, over responsiveness to cellular stressors, increases in DNA damage, and transcriptome-wide changes. Additionally, mutations in TARDBP confer a baseline increase in cytoplasmic TDP-43 thus suggesting that small changes in the subcellular localization of TDP-43 could in fact drive early pathology. In this review, we bring forth the theme of protein mislocalization as a key mechanism underlying ALS, by highlighting the importance of maintaining subcellular proteostasis along with the gain- and loss-of-functional consequences when TDP-43 localization is dysregulated. Additional research, focusing on early events in TDP-43 pathogenesis (i.e. to the protein mislocalization stage) will provide insight into disease mechanisms, therapeutic targets, and novel biomarkers for ALS.
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Affiliation(s)
- Terry R. Suk
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Maxime W. C. Rousseaux
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Eric Poulin Center for Neuromuscular Diseases, Ottawa, Canada
- Ottawa Institute of Systems Biology, Ottawa, Canada
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