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1.
Cell ; 177(3): 711-721.e8, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30982603

RESUMO

Yeast ataxin-2, also known as Pbp1, senses the activity state of mitochondria in order to regulate TORC1. A domain of Pbp1 required to adapt cells to mitochondrial activity is of low sequence complexity. The low-complexity (LC) domain of Pbp1 forms labile, cross-ß polymers that facilitate phase transition of the protein into liquid-like or gel-like states. Phase transition for other LC domains is reliant upon widely distributed aromatic amino acids. In place of tyrosine or phenylalanine residues prototypically used for phase separation, Pbp1 contains 24 similarly disposed methionine residues. Here, we show that the Pbp1 methionine residues are sensitive to hydrogen peroxide (H2O2)-mediated oxidation in vitro and in living cells. Methionine oxidation melts Pbp1 liquid-like droplets in a manner reversed by methionine sulfoxide reductase enzymes. These observations explain how reversible formation of labile polymers by the Pbp1 LC domain enables the protein to function as a sensor of cellular redox state.


Assuntos
Proteínas de Transporte/metabolismo , Metionina/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Proteínas de Transporte/química , Proteínas de Transporte/genética , Peróxido de Hidrogênio/farmacologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metionina/metabolismo , Metionina Sulfóxido Redutases/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mutagênese Sítio-Dirigida , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Transição de Fase , Domínios Proteicos , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética
2.
Annu Rev Biochem ; 87: 351-390, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29195049

RESUMO

In this review, we describe speculative ideas and early stage research concerning the flow of genetic information from the nuclear residence of genes to the disparate, cytoplasmic sites of protein synthesis. We propose that this process of information transfer is meticulously guided by transient structures formed from protein segments of low sequence complexity/intrinsic disorder. These low complexity domains are ubiquitously associated with regulatory proteins that control gene expression and RNA biogenesis, but they are also found in the central channel of nuclear pores, the nexus points of intermediate filament assembly, and the locations of action of other well-studied cellular proteins and pathways. Upon being organized into localized cellular positions via mechanisms utilizing properly folded protein domains, thereby facilitating elevated local concentration, certain low complexity domains adopt cross-ß interactions that are both structurally specific and labile to disassembly. These weakly tethered assemblies, we propose, are built to relay the passage of genetic information from one site to another within a cell, ensuring that the process is of extreme fidelity.


Assuntos
Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Modelos Biológicos , Animais , Grânulos Citoplasmáticos/genética , Grânulos Citoplasmáticos/metabolismo , Expressão Gênica , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Transtornos Heredodegenerativos do Sistema Nervoso/metabolismo , Humanos , Hidrogéis , Proteínas Intrinsicamente Desordenadas/química , Modelos Moleculares , Mutação , Domínios e Motivos de Interação entre Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína FUS de Ligação a RNA/química , Proteína FUS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/metabolismo
3.
Cell ; 171(3): 615-627.e16, 2017 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-28942918

RESUMO

Polymerization and phase separation of proteins containing low-complexity (LC) domains are important factors in gene expression, mRNA processing and trafficking, and localization of translation. We have used solid-state nuclear magnetic resonance methods to characterize the molecular structure of self-assembling fibrils formed by the LC domain of the fused in sarcoma (FUS) RNA-binding protein. From the 214-residue LC domain of FUS (FUS-LC), a segment of only 57 residues forms the fibril core, while other segments remain dynamically disordered. Unlike pathogenic amyloid fibrils, FUS-LC fibrils lack hydrophobic interactions within the core and are not polymorphic at the molecular structural level. Phosphorylation of core-forming residues by DNA-dependent protein kinase blocks binding of soluble FUS-LC to FUS-LC hydrogels and dissolves phase-separated, liquid-like FUS-LC droplets. These studies offer a structural basis for understanding LC domain self-assembly, phase separation, and regulation by post-translational modification.


Assuntos
Proteína FUS de Ligação a RNA/química , Sequência de Aminoácidos , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Fosforilação , Domínios Proteicos , Proteína FUS de Ligação a RNA/metabolismo
4.
Genes Dev ; 38(5-6): 205-212, 2024 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-38503517

RESUMO

This perspective begins with a speculative consideration of the properties of the earliest proteins to appear during evolution. What did these primitive proteins look like, and how were they of benefit to early forms of life? I proceed to hypothesize that primitive proteins have been preserved through evolution and now serve diverse functions important to the dynamics of cell morphology and biological regulation. The primitive nature of these modern proteins is easy to spot. They are composed of a limited subset of the 20 amino acids used by traditionally evolved proteins and thus are of low sequence complexity. This chemical simplicity limits protein domains of low sequence complexity to forming only a crude and labile type of protein structure currently hidden from the computational powers of machine learning. I conclude by hypothesizing that this structural weakness represents the underlying virtue of proteins that, at least for the moment, constitute the dark matter of the proteome.


Assuntos
Aminoácidos , Proteoma , Proteoma/química , Proteoma/metabolismo , Domínios Proteicos , Aminoácidos/metabolismo
5.
Cell ; 167(3): 789-802.e12, 2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27768897

RESUMO

Two complementary approaches were used in search of the intracellular targets of the toxic PR poly-dipeptide encoded by the repeat sequences expanded in the C9orf72 form of amyotrophic lateral sclerosis. The top categories of PRn-bound proteins include constituents of non-membrane invested cellular organelles and intermediate filaments. PRn targets are enriched for the inclusion of low complexity (LC) sequences. Evidence is presented indicating that LC sequences represent the direct target of PRn binding and that interaction between the PRn poly-dipeptide and LC domains is polymer-dependent. These studies indicate that PRn-mediated toxicity may result from broad impediments to the dynamics of cell structure and information flow from gene to message to protein.


Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Dipeptídeos/metabolismo , Demência Frontotemporal/metabolismo , Peptídeos/metabolismo , Proteínas/metabolismo , Esclerose Lateral Amiotrófica/genética , Proteína C9orf72 , Expansão das Repetições de DNA , Dipeptídeos/química , Dipeptídeos/genética , Demência Frontotemporal/genética , Células HeLa , Humanos , Proteínas de Filamentos Intermediários/metabolismo , Peptídeos/química , Peptídeos/genética , Domínios Proteicos , Proteínas/genética
6.
Cell ; 163(4): 829-39, 2015 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-26544936

RESUMO

Many DNA and RNA regulatory proteins contain polypeptide domains that are unstructured when analyzed in cell lysates. These domains are typified by an over-representation of a limited number of amino acids and have been termed prion-like, intrinsically disordered or low-complexity (LC) domains. When incubated at high concentration, certain of these LC domains polymerize into labile, amyloid-like fibers. Here, we report methods allowing the generation of a molecular footprint of the polymeric state of the LC domain of hnRNPA2. By deploying this footprinting technique to probe the structure of the native hnRNPA2 protein present in isolated nuclei, we offer evidence that its LC domain exists in a similar conformation as that described for recombinant polymers of the protein. These observations favor biologic utility to the polymerization of LC domains in the pathway of information transfer from gene to message to protein.


Assuntos
Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/química , Sequência de Aminoácidos , Animais , Núcleo Celular/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Humanos , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Schistosoma japonicum/enzimologia , Tirosina/análise
7.
Cell ; 158(6): 1324-1334, 2014 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-25215490

RESUMO

The P7C3 class of aminopropyl carbazole chemicals fosters the survival of neurons in a variety of rodent models of neurodegeneration or nerve cell injury. To uncover its mechanism of action, an active derivative of P7C3 was modified to contain both a benzophenone for photocrosslinking and an alkyne for CLICK chemistry. This derivative was found to bind nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme involved in the conversion of nicotinamide into nicotinamide adenine dinucleotide (NAD). Administration of active P7C3 chemicals to cells treated with doxorubicin, which induces NAD depletion, led to a rebound in intracellular levels of NAD and concomitant protection from doxorubicin-mediated toxicity. Active P7C3 variants likewise enhanced the activity of the purified NAMPT enzyme, providing further evidence that they act by increasing NAD levels through its NAMPT-mediated salvage.


Assuntos
NAD/metabolismo , Fármacos Neuroprotetores/farmacologia , Animais , Carbazóis/farmacologia , Linhagem Celular Tumoral , Células Cultivadas , Citocinas/agonistas , Citocinas/genética , Citocinas/metabolismo , Doxorrubicina/farmacologia , Humanos , Redes e Vias Metabólicas , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Nicotinamida Fosforribosiltransferase/genética , Nicotinamida Fosforribosiltransferase/metabolismo
8.
Cell ; 159(7): 1591-602, 2014 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-25525877

RESUMO

Acetyl-CoA represents a central node of carbon metabolism that plays a key role in bioenergetics, cell proliferation, and the regulation of gene expression. Highly glycolytic or hypoxic tumors must produce sufficient quantities of this metabolite to support cell growth and survival under nutrient-limiting conditions. Here, we show that the nucleocytosolic acetyl-CoA synthetase enzyme, ACSS2, supplies a key source of acetyl-CoA for tumors by capturing acetate as a carbon source. Despite exhibiting no gross deficits in growth or development, adult mice lacking ACSS2 exhibit a significant reduction in tumor burden in two different models of hepatocellular carcinoma. ACSS2 is expressed in a large proportion of human tumors, and its activity is responsible for the majority of cellular acetate uptake into both lipids and histones. These observations may qualify ACSS2 as a targetable metabolic vulnerability of a wide spectrum of tumors.


Assuntos
Acetato-CoA Ligase/metabolismo , Acetatos/metabolismo , Neoplasias/metabolismo , Acetato-CoA Ligase/análise , Acetato-CoA Ligase/genética , Acetilcoenzima A/metabolismo , Animais , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/metabolismo , Camundongos , Neoplasias/química , Neoplasias/patologia , Tomografia por Emissão de Pósitrons , Neoplasias de Mama Triplo Negativas/química , Neoplasias de Mama Triplo Negativas/patologia
9.
Cell ; 153(1): 56-69, 2013 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-23540690

RESUMO

Chemical modifications of histones and DNA, such as histone methylation, histone acetylation, and DNA methylation, play critical roles in epigenetic gene regulation. Many of the enzymes that add or remove such chemical modifications are known, or might be suspected, to be sensitive to changes in intracellular metabolism. This knowledge provides a conceptual foundation for understanding how mutations in the metabolic enzymes SDH, FH, and IDH can result in cancer and, more broadly, for how alterations in metabolism and nutrition might contribute to disease. Here, we review literature pertinent to hypothetical connections between metabolic and epigenetic states in eukaryotic cells.


Assuntos
Doença/genética , Epigênese Genética , Metabolismo , Acetilação , Animais , Metilação de DNA , Histonas/metabolismo , Humanos , Metilação
10.
Cell ; 155(5): 1049-1060, 2013 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-24267890

RESUMO

The low-complexity (LC) domains of the products of the fused in sarcoma (FUS), Ewings sarcoma (EWS), and TAF15 genes are translocated onto a variety of different DNA-binding domains and thereby assist in driving the formation of cancerous cells. In the context of the translocated fusion proteins, these LC sequences function as transcriptional activation domains. Here, we show that polymeric fibers formed from these LC domains directly bind the C-terminal domain (CTD) of RNA polymerase II in a manner reversible by phosphorylation of the iterated, heptad repeats of the CTD. Mutational analysis indicates that the degree of binding between the CTD and the LC domain polymers correlates with the strength of transcriptional activation. These studies offer a simple means of conceptualizing how RNA polymerase II is recruited to active genes in its unphosphorylated state and released for elongation following phosphorylation of the CTD.


Assuntos
RNA Polimerase II/química , RNA Polimerase II/metabolismo , Ativação Transcricional , Células HeLa , Humanos , Hidrogéis/química , Hidrogéis/metabolismo , Repetições de Microssatélites , Fosforilação , Polimerização , Estrutura Terciária de Proteína , Proteína EWS de Ligação a RNA/metabolismo , Proteína FUS de Ligação a RNA/química , Proteína FUS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/metabolismo , Fatores Associados à Proteína de Ligação a TATA/química , Fatores Associados à Proteína de Ligação a TATA/metabolismo
11.
Cell ; 150(6): 1100-2, 2012 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-22980972

RESUMO

The 2012 Albert Lasker Special Achievement Award in Medical Science will be shared by Donald Brown and Tom Maniatis for their scientific work leading to the purification and study of single genes by physical and molecular biological methodologies. Brown and Maniatis are also recognized for their extraordinary commitment and generosity in promoting the careers of young scientists. The impact of these accomplishments has transformed biological and medical science over the past four decades.


Assuntos
Distinções e Prêmios , Clonagem Molecular , Técnicas Genéticas , Biologia Molecular/história , Biologia Molecular/métodos , Genética/história , História do Século XX , Estados Unidos
12.
Cell ; 149(4): 768-79, 2012 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-22579282

RESUMO

Cellular granules lacking boundary membranes harbor RNAs and their associated proteins and play diverse roles controlling the timing and location of protein synthesis. Formation of such granules was emulated by treatment of mouse brain extracts and human cell lysates with a biotinylated isoxazole (b-isox) chemical. Deep sequencing of the associated RNAs revealed an enrichment for mRNAs known to be recruited to neuronal granules used for dendritic transport and localized translation at synapses. Precipitated mRNAs contain extended 3' UTR sequences and an enrichment in binding sites for known granule-associated proteins. Hydrogels composed of the low complexity (LC) sequence domain of FUS recruited and retained the same mRNAs as were selectively precipitated by the b-isox chemical. Phosphorylation of the LC domain of FUS prevented hydrogel retention, offering a conceptual means of dynamic, signal-dependent control of RNA granule assembly.


Assuntos
Encéfalo/citologia , RNA/análise , RNA/metabolismo , Ribonucleoproteínas/química , Animais , Biotinilação , Encéfalo/metabolismo , Linhagem Celular , Sistema Livre de Células , Humanos , Isoxazóis/metabolismo , Camundongos , Transporte de RNA , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo
13.
Cell ; 149(4): 753-67, 2012 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-22579281

RESUMO

Eukaryotic cells contain assemblies of RNAs and proteins termed RNA granules. Many proteins within these bodies contain KH or RRM RNA-binding domains as well as low complexity (LC) sequences of unknown function. We discovered that exposure of cell or tissue lysates to a biotinylated isoxazole (b-isox) chemical precipitated hundreds of RNA-binding proteins with significant overlap to the constituents of RNA granules. The LC sequences within these proteins are both necessary and sufficient for b-isox-mediated aggregation, and these domains can undergo a concentration-dependent phase transition to a hydrogel-like state in the absence of the chemical. X-ray diffraction and EM studies revealed the hydrogels to be composed of uniformly polymerized amyloid-like fibers. Unlike pathogenic fibers, the LC sequence-based polymers described here are dynamic and accommodate heterotypic polymerization. These observations offer a framework for understanding the function of LC sequences as well as an organizing principle for cellular structures that are not membrane bound.


Assuntos
Grânulos Citoplasmáticos/metabolismo , Hidrogel de Polietilenoglicol-Dimetacrilato/metabolismo , Proteínas de Ligação a RNA/análise , RNA/metabolismo , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Caenorhabditis elegans/citologia , Caenorhabditis elegans/metabolismo , Sistema Livre de Células , Grânulos Citoplasmáticos/química , Células-Tronco Embrionárias/metabolismo , Masculino , Camundongos , Modelos Moleculares , Células NIH 3T3 , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Testículo/citologia , Testículo/metabolismo , Difração de Raios X
14.
Proc Natl Acad Sci U S A ; 120(41): e2311416120, 2023 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-37782781

RESUMO

An evolutionarily conserved region of the TDP-43 low-complexity domain (LCD) twenty residues in length can adopt either an α-helical or ß-strand conformation. When in the latter conformation, TDP-43 self-associates via the formation of a labile, cross-ß structure. Self-association can be monitored via the formation of phase-separated protein droplets. Exposure of droplets to hydrogen peroxide leads to oxidation of conserved methionine residues distributed throughout the LCD. Oxidation disassembles the cross-ß structure, thus eliminating both self-association and phase separation. Here, we demonstrate that this process reciprocally enables formation of α-helical structure in precisely the same region formerly functioning to facilitate ß-strand-mediated self-association. We further observe that the α-helical conformation allows interaction with a lipid-like detergent and that exposure to lipids enhances the ß-to-α conformational switch. We hypothesize that regulation of this oxidative switch will prove to be important to the control of localized translation within vertebrate cells. The experimental observations reported herein were heavily reliant on studies of 1,6-hexanediol, a chemical agent that selectively dissolves labile structures formed via the self-association of protein domains of low sequence complexity. This aliphatic alcohol is shown to exert its dissociative activity primarily via hydrogen-bonding interactions with carbonyl oxygen atoms of the polypeptide backbone. Such observations underscore the central importance of backbone-mediated protein:protein interactions that facilitate the self-association and phase separation of LCDs.


Assuntos
Proteínas de Ligação a DNA , Peptídeos , Proteínas de Ligação a DNA/metabolismo , Peptídeos/química , Domínios Proteicos , Metionina/metabolismo , Estresse Oxidativo
15.
Cell ; 142(1): 39-51, 2010 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-20603013

RESUMO

An in vivo screen was performed in search of chemicals capable of enhancing neuron formation in the hippocampus of adult mice. Eight of 1000 small molecules tested enhanced neuron formation in the subgranular zone of the dentate gyrus. Among these was an aminopropyl carbazole, designated P7C3, endowed with favorable pharmacological properties. In vivo studies gave evidence that P7C3 exerts its proneurogenic activity by protecting newborn neurons from apoptosis. Mice missing the gene encoding neuronal PAS domain protein 3 (NPAS3) are devoid of hippocampal neurogenesis and display malformation and electrophysiological dysfunction of the dentate gyrus. Prolonged administration of P7C3 to npas3(-/-) mice corrected these deficits by normalizing levels of apoptosis of newborn hippocampal neurons. Prolonged administration of P7C3 to aged rats also enhanced neurogenesis in the dentate gyrus, impeded neuron death, and preserved cognitive capacity as a function of terminal aging. PAPERCLIP:


Assuntos
Carbazóis/farmacologia , Avaliação Pré-Clínica de Medicamentos , Neurogênese/efeitos dos fármacos , Neurônios/citologia , Fármacos Neuroprotetores/farmacologia , Envelhecimento/efeitos dos fármacos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Carbazóis/química , Cognição/efeitos dos fármacos , Giro Denteado/citologia , Giro Denteado/fisiologia , Feminino , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Fármacos Neuroprotetores/química , Ratos
16.
RNA ; 28(1): 3-15, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34670847

RESUMO

This review covers research findings reported over the past decade concerning the ability of low complexity (LC) domains to self-associate in a manner leading to their phase separation from aqueous solution. We focus our message upon the reductionist use of two forms of phase separation as biochemical assays to study how LC domains might function in living cells. Cells and their varied compartments represent extreme examples of material condensates. Over the past half century, biochemists, structural biologists, and molecular biologists have resolved the mechanisms driving innumerable forms of macromolecular condensation. In contrast, we remain largely ignorant as to how 10%-20% of our proteins actually work to assist in cell organization. This enigmatic 10%-20% of the proteome corresponds to gibberish-like LC sequences. We contend that many of these LC sequences move in and out of a structurally ordered, self-associated state as a means of offering a combination of organizational specificity and dynamic pliability to living cells. Finally, we speculate that ancient proteins may have behaved similarly, helping to condense, organize, and protect RNA early during evolution.


Assuntos
Condensados Biomoleculares/química , Células Eucarióticas/química , Glicóis/química , Isoxazóis/química , Proteínas/química , RNA/química , Condensados Biomoleculares/metabolismo , Eucariotos , Células Eucarióticas/metabolismo , Hidrogéis/química , Hidrogéis/metabolismo , Ligação de Hidrogênio , Metionina/química , Metionina/metabolismo , Origem da Vida , Conformação Proteica em Folha beta , Domínios Proteicos , Proteínas/metabolismo , RNA/metabolismo , Soluções , Água/química , Água/metabolismo
17.
Cell ; 138(5): 817-9, 2009 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-19737508

RESUMO

Science is an "endless frontier," and opportunities for transformative discovery abound. The young scientist will profit by paying mind to two forms of balance: the contrast between depth and breadth in training, and the contrast between hypothesis-driven research and random inquiry into the unknown.


Assuntos
Disciplinas das Ciências Biológicas/tendências , Pesquisa Biomédica/tendências , Disciplinas das Ciências Biológicas/educação , Disciplinas das Ciências Biológicas/métodos , Pesquisa Biomédica/educação , Pesquisa Biomédica/métodos
18.
Proc Natl Acad Sci U S A ; 118(42)2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34654750

RESUMO

The low-complexity (LC) domain of the fused in sarcoma (FUS) RNA binding protein self-associates in a manner causing phase separation from an aqueous environment. Incubation of the FUS LC domain under physiologically normal conditions of salt and pH leads to rapid formation of liquid-like droplets that mature into a gel-like state. Both examples of phase separation have enabled reductionist biochemical assays allowing discovery of an N-terminal region of 57 residues that assembles into a labile, cross-ß structure. Here we provide evidence of a nonoverlapping, C-terminal region of the FUS LC domain that also forms specific cross-ß interactions. We propose that biologic function of the FUS LC domain may operate via the mutually exclusive use of these N- and C-terminal cross-ß cores. Neurodegenerative disease-causing mutations in the FUS LC domain are shown to imbalance the two cross-ß cores, offering an unanticipated concept of LC domain function and dysfunction.


Assuntos
Domínios Proteicos , Proteína FUS de Ligação a RNA/metabolismo , Substituição de Aminoácidos , Esclerose Lateral Amiotrófica/metabolismo , Humanos , Hidrogéis , Proteína FUS de Ligação a RNA/química
19.
Proc Natl Acad Sci U S A ; 118(8)2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33593918

RESUMO

Low complexity (LC) head domains 92 and 108 residues in length are, respectively, required for assembly of neurofilament light (NFL) and desmin intermediate filaments (IFs). As studied in isolation, these IF head domains interconvert between states of conformational disorder and labile, ß-strand-enriched polymers. Solid-state NMR (ss-NMR) spectroscopic studies of NFL and desmin head domain polymers reveal spectral patterns consistent with structural order. A combination of intein chemistry and segmental isotope labeling allowed preparation of fully assembled NFL and desmin IFs that could also be studied by ss-NMR. Assembled IFs revealed spectra overlapping with those observed for ß-strand-enriched polymers formed from the isolated NFL and desmin head domains. Phosphorylation and disease-causing mutations reciprocally alter NFL and desmin head domain self-association yet commonly impede IF assembly. These observations show how facultative structural assembly of LC domains via labile, ß-strand-enriched self-interactions may broadly influence cell morphology.


Assuntos
Desmina/química , Desmina/metabolismo , Filamentos Intermediários/química , Filamentos Intermediários/metabolismo , Humanos , Fosforilação , Conformação Proteica , Domínios Proteicos
20.
Trends Biochem Sci ; 44(11): 899-901, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31629612

RESUMO

mRNAs move to the right place in cells to facilitate localized translation. The pathway of mRNA movement involves nuclear and cytoplasmic puncta not surrounded by investing membranes. Discoveries reported by Hondele et al. explain how mRNA molecules can be passed from one puncta to another, forming a relay that directs mRNAs to their proper location.


Assuntos
Adenosina Trifosfatases , Núcleo Celular , Citoplasma , RNA Helicases DEAD-box , RNA Mensageiro
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