共查询到20条相似文献,搜索用时 31 毫秒
1.
The mechanism by which mutations in TAR DNA‐binding protein 43 (TDP‐43) cause neurodegeneration remains incompletely understood. In this issue of The EMBO Journal, Fratta et al ( 2018 ) describe how a point mutation in the C‐terminal low complexity domain of TDP‐43 leads to the skipping of otherwise constitutively conserved exons. In vivo, this mutation triggers late‐onset progressive neuromuscular disturbances, as seen in amyotrophic lateral sclerosis (ALS), suggesting that TDP‐43 splicing gain‐of‐function contributes to ALS pathogenesis. 相似文献
2.
3.
4.
A single N‐terminal phosphomimic disrupts TDP‐43 polymerization,phase separation,and RNA splicing 下载免费PDF全文
Hermann Broder Schmidt Erik W Martin Shannon N Rhoads Ashley N Reeb Amanda Nourse Daniel Ramirez Montero Veronica H Ryan Rajat Rohatgi Frank Shewmaker Mandar T Naik Tanja Mittag Yuna M Ayala Nicolas L Fawzi 《The EMBO journal》2018,37(5)
TDP‐43 is an RNA‐binding protein active in splicing that concentrates into membraneless ribonucleoprotein granules and forms aggregates in amyotrophic lateral sclerosis (ALS) and Alzheimer's disease. Although best known for its predominantly disordered C‐terminal domain which mediates ALS inclusions, TDP‐43 has a globular N‐terminal domain (NTD). Here, we show that TDP‐43 NTD assembles into head‐to‐tail linear chains and that phosphomimetic substitution at S48 disrupts TDP‐43 polymeric assembly, discourages liquid–liquid phase separation (LLPS) in vitro, fluidizes liquid–liquid phase separated nuclear TDP‐43 reporter constructs in cells, and disrupts RNA splicing activity. Finally, we present the solution NMR structure of a head‐to‐tail NTD dimer comprised of two engineered variants that allow saturation of the native polymerization interface while disrupting higher‐order polymerization. These data provide structural detail for the established mechanistic role of the well‐folded TDP‐43 NTD in splicing and link this function to LLPS. In addition, the fusion‐tag solubilized, recombinant form of TDP‐43 full‐length protein developed here will enable future phase separation and in vitro biochemical assays on TDP‐43 function and interactions that have been hampered in the past by TDP‐43 aggregation. 相似文献
5.
Qin Xia Hongfeng Wang Zongbing Hao Cheng Fu Qingsong Hu Feng Gao Haigang Ren Dong Chen Junhai Han Zheng Ying Guanghui Wang 《The EMBO journal》2016,35(2):121-142
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is characterized by selective loss of motor neurons in brain and spinal cord. TAR DNA‐binding protein 43 (TDP‐43) was identified as a major component of disease pathogenesis in ALS, frontotemporal lobar degeneration (FTLD), and other neurodegenerative disease. Despite the fact that TDP‐43 is a multi‐functional protein involved in RNA processing and a large number of TDP‐43 RNA targets have been discovered, the initial toxic effect and the pathogenic mechanism underlying TDP‐43‐linked neurodegeneration remain elusive. In this study, we found that loss of TDP‐43 strongly induced a nuclear translocation of TFEB, the master regulator of lysosomal biogenesis and autophagy, through targeting the mTORC1 key component raptor. This regulation in turn enhanced global gene expressions in the autophagy–lysosome pathway (ALP) and increased autophagosomal and lysosomal biogenesis. However, loss of TDP‐43 also impaired the fusion of autophagosomes with lysosomes through dynactin 1 downregulation, leading to accumulation of immature autophagic vesicles and overwhelmed ALP function. Importantly, inhibition of mTORC1 signaling by rapamycin treatment aggravated the neurodegenerative phenotype in a TDP‐43‐depleted Drosophila model, whereas activation of mTORC1 signaling by PA treatment ameliorated the neurodegenerative phenotype. Taken together, our data indicate that impaired mTORC1 signaling and influenced ALP may contribute to TDP‐43‐mediated neurodegeneration. 相似文献
6.
Amyotrophic Lateral Sclerosis (ALS) is a devastating adult onset neurodegenerative disease affecting both upper and lower motor neurons. TDP-43, encoded by the TARDBP gene, was identified as a component of motor neuron cytoplasmic inclusions in both familial and sporadic ALS and has become a pathological signature of the disease. TDP-43 is a nuclear protein involved in RNA metabolism, however in ALS, TDP-43 is mislocalized to the cytoplasm of affected motor neurons, suggesting that disease might be caused by TDP-43 loss of function. To investigate this hypothesis, we attempted to generate a mouse conditional knockout of the Tardbp gene using the classical Cre-loxP technology. Even though heterozygote mice for the targeted allele were successfully generated, we were unable to obtain homozygotes. Here we show that although the targeting vector was specifically designed to not overlap with Tardbp adjacent genes, the homologous recombination event affected the expression of a downstream gene, Masp2. This may explain the inability to obtain homozygote mice with targeted Tardbp. 相似文献
7.
It is well established that TDP‐43 accumulates in degenerating neurons in patients with ALS/FTLD, which might affect normal TDP‐43 function. In this issue of The EMBO Journal Xia et al ( 2016 ) show a novel connection between TDP‐43 loss of function and autophagy failure. Using knockdown models of TDP‐43, they observed enhanced autophagosome and lysosome biogenesis through mTORC1 activity inhibition and TFEB activation. Impaired autophagosome–lysosome fusion was also observed, however in an mTORC1‐independent manner. The data identify dysfunctions at multiple stages of the autophagic pathway following TDP‐43 depletion that might represent possible targets of future therapeutic interventions. 相似文献
8.
9.
10.
Fabienne C Fiesel Aaron Voigt Stephanie S Weber Chris Van den Haute Andrea Waldenmaier Karin Görner Michael Walter Marlene L Anderson Jeannine V Kern Tobias M Rasse Thorsten Schmidt Wolfdieter Springer Roland Kirchner Michael Bonin Manuela Neumann Veerle Baekelandt Marianna Alunni‐Fabbroni Jörg B Schulz Philipp J Kahle 《The EMBO journal》2010,29(1):209-221
11.
Aberrant localization of FUS and TDP43 is associated with misfolding of SOD1 in amyotrophic lateral sclerosis 总被引:1,自引:0,他引:1
Background
Amyotrophic lateral sclerosis (ALS) is incurable and characterized by progressive paralysis of the muscles of the limbs, speech and swallowing, and respiration due to the progressive degeneration of voluntary motor neurons. Clinically indistinguishable ALS can be caused by genetic mutations of Cu/Zn superoxide dismutase (SOD1), TAR-DNA binding protein 43 (TDP43), or fused in sarcoma/translocated in liposarcoma (FUS/TLS), or can occur in the absence of known mutation as sporadic disease. In this study, we tested the hypothesis that FUS/TLS and TDP43 gain new pathogenic functions upon aberrant accumulation in the cytosol that directly or indirectly include misfolding of SOD1.Methodology/Principal Findings
Patient spinal cord necropsy immunohistochemistry with SOD1 misfolding-specific antibodies revealed misfolded SOD1 in perikarya and motor axons of SOD1-familial ALS (SOD1-FALS), and in motor axons of R521C-FUS FALS and sporadic ALS (SALS) with cytoplasmic TDP43 inclusions. SOD1 misfolding and oxidation was also detected using immunocytochemistry and quantitative immunoprecipitation of human neuroblastoma SH-SY5Y cells as well as cultured murine spinal neural cells transgenic for human wtSOD1, which were transiently transfected with human cytosolic mutant FUS or TDP43, or wtTDP43.Conclusion/Significance
We conclude that cytosolic mislocalization of FUS or TDP43 in vitro and ALS in vivo may kindle wtSOD1 misfolding in non-SOD1 FALS and SALS. The lack of immunohistochemical compartmental co-localization of misfolded SOD1 with cytosolic TDP43 or FUS suggests an indirect induction of SOD1 misfolding followed by propagation through template directed misfolding beyond its site of inception. The identification of a final common pathway in the molecular pathogenesis of ALS provides a treatment target for this devastating disease. 相似文献12.
13.
Megumi Narukawa‐Nara Ayako Nakamura Ko Kikuzato Yusuke Kakei Akiko Sato Yuka Mitani Yumiko Yamasaki‐Kokudo Takahiro Ishii Ken‐ichiro Hayashi Tadao Asami Takehiko Ogura Shigeo Yoshida Shozo Fujioka Takashi Kamakura Tsutomu Kawatsu Masanori Tachikawa Kazuo Soeno Yukihisa Shimada 《The Plant journal : for cell and molecular biology》2016,87(3):245-257
We previously reported l ‐α‐aminooxy‐phenylpropionic acid (AOPP) to be an inhibitor of auxin biosynthesis, but its precise molecular target was not identified. In this study we found that AOPP targets TRYPTOPHAN AMINOTRANSFERASE of ARABIDOPSIS 1 (TAA1). We then synthesized 14 novel compounds derived from AOPP to study the structure–activity relationships of TAA1 inhibitors in vitro. The aminooxy and carboxy groups of the compounds were essential for inhibition of TAA1 in vitro. Docking simulation analysis revealed that the inhibitory activity of the compounds was correlated with their binding energy with TAA1. These active compounds reduced the endogenous indole‐3‐acetic acid (IAA) content upon application to Arabidopsis seedlings. Among the compounds, we selected 2‐(aminooxy)‐3‐(naphthalen‐2‐yl)propanoic acid (KOK1169/AONP) and analyzed its activities in vitro and in vivo. Arabidopsis seedlings treated with KOK1169 showed typical auxin‐deficient phenotypes, which were reversed by exogenous IAA. In vitro and in vivo experiments indicated that KOK1169 is more specific for TAA1 than other enzymes, such as phenylalanine ammonia‐lyase. We further tested 41 novel compounds with aminooxy and carboxy groups to which we added protection groups to increase their calculated hydrophobicity. Most of these compounds decreased the endogenous auxin level to a greater degree than the original compounds, and resulted in a maximum reduction of about 90% in the endogenous IAA level in Arabidopsis seedlings. We conclude that the newly developed compounds constitute a class of inhibitors of TAA1. We designated them ‘pyruvamine’. 相似文献
14.
Luan T. Tran Benoit J. Gentil Kathleen E. Sullivan Heather D. Durham 《Journal of neurochemistry》2014,130(3):455-466
Excitotoxicity and disruption of Ca2+ homeostasis have been implicated in amyotrophic lateral sclerosis (ALS) and limiting Ca2+ entry is protective in models of ALS caused by mutation of SOD1. Lomerizine, an antagonist of L‐ and T‐type voltage‐gated calcium channels and transient receptor potential channel 5 transient receptor potential channels, is well tolerated clinically, making it a potential therapeutic candidate. Lomerizine reduced glutamate excitotoxicity in cultured motor neurons by reducing the accumulation of cytoplasmic Ca2+ and protected motor neurons against multiple measures of mutant SOD1 toxicity: Ca2+ overload, impaired mitochondrial trafficking, mitochondrial fragmentation, formation of mutant SOD1 inclusions, and loss of viability. To assess the utility of lomerizine in other forms of ALS, calcium homeostasis was evaluated in culture models of disease because of mutations in the RNA‐binding proteins transactive response DNA‐binding protein 43 (TDP‐43) and Fused in Sarcoma (FUS). Calcium did not play the same role in the toxicity of these mutant proteins as with mutant SOD1 and lomerizine failed to prevent cytoplasmic accumulation of mutant TDP‐43, a hallmark of its pathology. These experiments point to differences in the pathogenic pathways between types of ALS and show the utility of primary culture models in comparing those mechanisms and effectiveness of therapeutic strategies.
15.
TMEM106B variants are genetically associated with frontotemporal lobar degeneration with TDP‐43 pathology (FTLD‐TDP), and are considered a major risk factor for this disease. As TMEM106B may be involved in other pathologies such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), uncovering its cellular functions has become a priority. In this issue of The EMBO Journal, Schwenk et al ( 2014 ) combine loss‐of‐function experiments, live imaging and proteomics to unveil the physiological roles played by TMEM106B and its binding partner MAP6 in lysosomal function and transport. 相似文献
16.
Ya-Fei Xu Mercedes Prudencio Jaime M. Hubbard Jimei Tong Ena C. Whitelaw Karen Jansen-West Caroline Stetler Xiangkun Cao John Song Yong-Jie Zhang 《PloS one》2013,8(7)
Tar DNA binding protein 43 (TDP-43) is the major component of pathological deposits in frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP) and in amyotrophic lateral sclerosis (ALS). It has been reported that TDP-43 transgenic mouse models expressing human TDP-43 wild-type or ALS-associated mutations recapitulate certain ALS and FTLD pathological phenotypes. Of note, expression of human TDP-43 (hTDP-43) reduces the levels of mouse Tdp-43 (mTdp-43). However, it remained unclear whether the mechanisms through which TDP-43 induces ALS or FTLD-like pathologies resulted from a reduction in mTdp-43, an increase in hTDP-43, or a combination of both. In elucidating the role of mTdp-43 and hTDP-43 in hTDP-43 transgenic mice, we observed that reduction of mTdp-43 in non-transgenic mice by intraventricular brain injection of AAV1-shTardbp leads to a dramatic increase in the levels of splicing variants of mouse sortilin 1 and translin. However, the levels of these two abnormal splicing variants are not increased in hTDP-43 transgenic mice despite significant downregulation of mTdp-43 in these mice. Moreover, further downregulation of mTdp-43 in hTDP-43 hemizygous mice, which are asymptomatic, to the levels equivalent to that of mTdp-43 in hTDP-43 homozygous mice does not induce the pathological phenotypes observed in the homozygous mice. Lastly, the number of dendritic spines and the RNA levels of TDP-43 RNA targets critical for synapse formation and function are significantly decreased in symptomatic homozygous mice. Together, our findings indicate that mTdp-43 downregulation does not lead to a loss of function mechanism or account for the pathological phenotypes observed in hTDP-43 homozygous mice because hTDP-43 compensates for the reduction, and associated functions of mTdp-43. Rather, expression of hTDP-43 beyond a certain threshold leads to abnormal metabolism of TDP-43 RNA targets critical for neuronal structure and function, which might be responsible for the ALS or FTLD-like pathologies observed in homozygous hTDP-43 transgenic mice. 相似文献
17.
Dimer/monomer status and in vivo function of salt‐bridge mutants of the plant UV‐B photoreceptor UVR8 下载免费PDF全文
Monika Heilmann Christos N. Velanis Catherine Cloix Brian O. Smith John M. Christie Gareth I. Jenkins 《The Plant journal : for cell and molecular biology》2016,88(1):71-81
UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor for ultraviolet‐B (UV‐B) light that initiates photomorphogenic responses in plants. UV‐B photoreception causes rapid dissociation of dimeric UVR8 into monomers that interact with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) to initiate signal transduction. Experiments with purified UVR8 show that the dimer is maintained by salt‐bridge interactions between specific charged amino acids across the dimer interface. However, little is known about the importance of these charged amino acids in determining dimer/monomer status and UVR8 function in plants. Here we evaluate the use of different methods to examine dimer/monomer status of UVR8 and show that mutations of several salt‐bridge amino acids affect dimer/monomer status, interaction with COP1 and photoreceptor function of UVR8 in vivo. In particular, the salt‐bridges formed between arginine 286 and aspartates 96 and 107 are key to dimer formation. Mutation of arginine 286 to alanine impairs dimer formation, interaction with COP1 and function in vivo, whereas mutation to lysine gives a weakened dimer that is functional in vivo, indicating the importance of the positive charge of the arginine/lysine residue for dimer formation. Notably, a UVR8 mutant in which aspartates 96 and 107 are conservatively mutated to asparagine is strongly impaired in dimer formation but mediates UV‐B responses in vivo with a similar dose–response relationship to wild‐type. The UV‐B responsiveness of this mutant does not correlate with dimer formation and monomerisation, indicating that monomeric UVR8 has the potential for UV‐B photoreception, initiating signal transduction and responses in plants. 相似文献
18.
Linc00511 acts as a competing endogenous RNA to regulate VEGFA expression through sponging hsa‐miR‐29b‐3p in pancreatic ductal adenocarcinoma 下载免费PDF全文
Shangyou Zheng Zairui Wang Wenzhu Li Zhuofei Bi Liting Li Yanhui Jiang Yuming Luo Qing Lin Zhiqiang Fu Chen Rufu 《Journal of cellular and molecular medicine》2018,22(1):655-667
Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy. Long non‐coding RNAs (lncRNAs) are important regulators in pathological processes, yet their potential roles in PDAC are poorly understood. Here, we identify a fundamental role for a novel lincRNA, linc00511, in the progression of PDAC. Linc00511 levels in PDAC tissue specimens and cell lines were examined by quantitative real‐time PCR. Corresponding adjacent non‐neoplastic tissues were used as controls. The function of linc00511 in PDAC cell lines was determined by RNA interference approach in vitro and in vivo. Fluorescence in situ hybridization (FISH) was used to characterize linc00511 expression in PDAC cells. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were obtained from bioinformatic analysis, luciferase assays and RIP assays. The association between the linc00511/hsa‐miR29b‐3p axis and VEGFA was verified by Western blotting assay. Immunohistochemistry was performed to evaluate the expression of VEGFA in PDAC samples. The aberrant up‐regulation of linc00511 was detected in PDAC cell lines and patient specimens compared with controls. An increase in linc00511 expression indicates the adverse clinical pathological characteristics and poor prognosis. Functionally, linc00511 depletion in PDAC cells decreased proliferation, migration, invasion and endothelial tube formation. Mechanistically, linc00511 could up‐regulate VEGFA via its competing endogenous RNA (ceRNA) activity on hsa‐miR‐29b‐3p. In summary, our results define an important axis controlling proliferation, invasion and tumour angiogenesis in PDAC. Linc00511 is a novel lncRNA that plays a significant regulatory role in the pathogenesis and progression of PDAC. Thus, Linc00511 represents a new prognostic biomarker to predict clinical outcome of PDAC patients after surgery and may serve as a potential therapeutic target for PDAC treatment. 相似文献
19.
Amy M. James Joel Haywood Julie Leroux Katarzyna Ignasiak Alysha G. Elliott Jason W. Schmidberger Mark F. Fisher Samuel G. Nonis Ricarda Fenske Charles S. Bond Joshua S. Mylne 《The Plant journal : for cell and molecular biology》2019,98(6):988-999
Plant asparaginyl endopeptidases (AEPs) are expressed as inactive zymogens that perform maturation of seed storage protein upon cleavage‐dependent autoactivation in the low‐pH environment of storage vacuoles. The AEPs have attracted attention for their macrocyclization reactions, and have been classified as cleavage or ligation specialists. However, we have recently shown that the ability of AEPs to produce either cyclic or acyclic products can be altered by mutations to the active site region, and that several AEPs are capable of macrocyclization given favorable pH conditions. One AEP extracted from Clitoria ternatea seeds (butelase 1) is classified as a ligase rather than a protease, presenting an opportunity to test for loss of cleavage activity. Here, making recombinant butelase 1 and rescuing an Arabidopsis thaliana mutant lacking AEP, we show that butelase 1 retains cleavage functions in vitro and in vivo. The in vivo rescue was incomplete, consistent with some trade‐off for butelase 1 specialization toward macrocyclization. Its crystal structure showed an active site with only subtle differences from cleaving AEPs, suggesting the many differences in its peptide‐binding region are the source of its efficient macrocyclization. All considered, it seems that either butelase 1 has not fully specialized or a requirement for autocatalytic cleavage is an evolutionary constraint upon macrocyclizing AEPs. 相似文献
20.