scholarly journals Functional Anatomy of the TDP-43 Redox Sensor

2021 ◽  
Author(s):  
Xiaoming Zhou ◽  
Lily Sumrow ◽  
Lillian Sutherland ◽  
Daifei Liu ◽  
Tian Qin ◽  
...  

AbstractTAR binding protein 43 (TDP-43) is an RNA binding protein that assists in the maturation, export and sub-cellular localization of mRNA. The carboxyl terminal 153 residues of TDP-43 are of low sequence complexity and allow for self-association of the protein in a manner leading to its phase separation from an aqueous environment. These interactions assist TDP-43 in forming cytoplasmic RNA granules involved in the transport of mRNA for localized translation. Self-association of the TDP-43 low complexity (LC) domain is facilitated by a region of twenty five residues that are of extreme evolutionary conservation. The molecular basis for self-adherence of the protein through this region has been illuminated by a combination of structural and biochemical studies, allowing definition of a morphologically specific cross-β structure predicted to be weakly assembled by main chain hydrogen bonds. In this study we have investigated the importance of individual, Pauling hydrogen bonds hypothesized to facilitate self-adherence of the TDP-43 LC domain.

2021 ◽  
Vol 118 (42) ◽  
pp. e2114412118
Author(s):  
Masato Kato ◽  
Steven L. McKnight

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-β structure. Here we provide evidence of a nonoverlapping, C-terminal region of the FUS LC domain that also forms specific cross-β 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-β cores. Neurodegenerative disease–causing mutations in the FUS LC domain are shown to imbalance the two cross-β cores, offering an unanticipated concept of LC domain function and dysfunction.


2017 ◽  
Vol 474 (8) ◽  
pp. 1417-1438 ◽  
Author(s):  
Alice Ford Harrison ◽  
James Shorter

Approximately 70 human RNA-binding proteins (RBPs) contain a prion-like domain (PrLD). PrLDs are low-complexity domains that possess a similar amino acid composition to prion domains in yeast, which enable several proteins, including Sup35 and Rnq1, to form infectious conformers, termed prions. In humans, PrLDs contribute to RBP function and enable RBPs to undergo liquid–liquid phase transitions that underlie the biogenesis of various membraneless organelles. However, this activity appears to render RBPs prone to misfolding and aggregation connected to neurodegenerative disease. Indeed, numerous RBPs with PrLDs, including TDP-43 (transactivation response element DNA-binding protein 43), FUS (fused in sarcoma), TAF15 (TATA-binding protein-associated factor 15), EWSR1 (Ewing sarcoma breakpoint region 1), and heterogeneous nuclear ribonucleoproteins A1 and A2 (hnRNPA1 and hnRNPA2), have now been connected via pathology and genetics to the etiology of several neurodegenerative diseases, including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Here, we review the physiological and pathological roles of the most prominent RBPs with PrLDs. We also highlight the potential of protein disaggregases, including Hsp104, as a therapeutic strategy to combat the aberrant phase transitions of RBPs with PrLDs that likely underpin neurodegeneration.


Planta ◽  
2006 ◽  
Vol 225 (6) ◽  
pp. 1339-1351 ◽  
Author(s):  
Adriana Flores Fusaro ◽  
Silvia Nora Bocca ◽  
Rose Lucia Braz Ramos ◽  
Rosa Maria Barrôco ◽  
Claudia Magioli ◽  
...  

2008 ◽  
Vol 36 (4) ◽  
pp. 641-647 ◽  
Author(s):  
Kirsty Sawicka ◽  
Martin Bushell ◽  
Keith A. Spriggs ◽  
Anne E. Willis

PTB (polypyrimidine-tract-binding protein) is a ubiquitous RNA-binding protein. It was originally identified as a protein with a role in splicing but it is now known to function in a large number of diverse cellular processes including polyadenylation, mRNA stability and translation initiation. Specificity of PTB function is achieved by a combination of changes in the cellular localization of this protein (its ability to shuttle from the nucleus to the cytoplasm is tightly controlled) and its interaction with additional proteins. These differences in location and trans-acting factor requirements account for the fact that PTB acts both as a suppressor of splicing and an activator of translation. In the latter case, the role of PTB in translation has been studied extensively and it appears that this protein is required for an alternative form of translation initiation that is mediated by a large RNA structural element termed an IRES (internal ribosome entry site) that allows the synthesis of picornaviral proteins and cellular proteins that function to control cell growth and cell death. In the present review, we discuss how PTB regulates these disparate processes.


2019 ◽  
Author(s):  
Yi Lin ◽  
Xiaoming Zhou ◽  
Masato Kato ◽  
Daifei Liu ◽  
Sina Ghaemmaghami ◽  
...  

SummaryAn evolutionarily conserved low complexity (LC) domain is found within a 152 residue segment localized to the carboxyl-terminal region of the TDP43 RNA-binding protein. This TDP43 LC domain contains ten conserved methionine residues. Self-association of this domain leads to the formation of liquid-like droplets composed of labile, cross-β polymers. Exposure of polymers to low concentrations of H2O2 leads to a phenomenon of droplet melting that can be reversed upon exposure of the oxidized protein to the MsrA and MsrB methionine sulfoxide reductase enzymes, thioredoxin, thioredoxin reductase and NADPH. Morphological features of the cross-β polymers were revealed by a method of H2O2-mediated footprinting. Similar TDP43 LC domain footprints were observed in highly polymerized, hydrogel samples, liquid-like droplet samples, and living cells. The ability of H2O2 to impede cross-β polymerization was abrogated by a prominent ALS-causing mutation that changes methionine residue 337 to valine. These observations offer potentially useful insight into the biological role of TDP43 in facilitating synapse-localized translation, as well as aberrant aggregation of the protein in neurodegenerative disease.


Acta Naturae ◽  
2017 ◽  
Vol 9 (2) ◽  
pp. 4-16 ◽  
Author(s):  
E. E. Alemasova ◽  
O. I. Lavrik

RNA-binding proteins (RBPs) regulate RNA metabolism, from synthesis to decay. When bound to RNA, RBPs act as guardians of the genome integrity at different levels, from DNA damage prevention to the post-transcriptional regulation of gene expression. Recently, RBPs have been shown to participate in DNA repair. This fact is of special interest as DNA repair pathways do not generally involve RNA. DNA damage in higher organisms triggers the formation of the RNA-like polymer - poly(ADP-ribose) (PAR). Nucleic acid-like properties allow PAR to recruit DNA- and RNA-binding proteins to the site of DNA damage. It is suggested that poly(ADP-ribose) and RBPs not only modulate the activities of DNA repair factors, but that they also play an important role in the formation of transient repairosome complexes in the nucleus. Cytoplasmic biomolecules are subjected to similar sorting during the formation of RNA assemblages by functionally related mRNAs and promiscuous RBPs. The Y-box-binding protein 1 (YB-1) is the major component of cytoplasmic RNA granules. Although YB-1 is a classic RNA-binding protein, it is now regarded as a non-canonical factor of DNA repair.


Author(s):  
Daniil M. Prigozhin ◽  
Anna Albecka ◽  
Christopher H. Douse ◽  
Iva A. Tchasovnikarova ◽  
Richard T. Timms ◽  
...  

AbstractTranscription of integrated DNA from viruses or transposable elements is tightly regulated to prevent pathogenesis. The Human Silencing Hub (HUSH), composed of Periphilin, TASOR and MPP8, silences transcriptionally active viral and endogenous transgenes. HUSH recruits effectors that alter the epigenetic landscape and chromatin structure, but how HUSH recognizes target loci and represses their expression remains unclear. We identify the physicochemical properties of Periphilin necessary for HUSH assembly and silencing. A disordered N-terminal domain (NTD) and structured C-terminal domain are essential for silencing. A crystal structure of the Periphilin-TASOR core complex shows Periphilin forms α-helical homodimers, which each bind a single TASOR molecule. The NTD binds RNA non-specifically and forms insoluble aggregates through an arginine/tyrosine-rich sequence reminiscent of low-complexity regions from self-associating RNA-binding proteins. Residues required for TASOR binding and aggregation were required for HUSH-dependent silencing and genome-wide deposition of repressive mark H3K9me3. The NTD was functionally complemented by low-complexity regions from certain RNA-binding proteins and proteins that form condensates or fibrils. Our work suggests the associative properties of Periphilin promote HUSH aggregation on nascent transcripts.


2020 ◽  
Vol 117 (46) ◽  
pp. 28727-28734
Author(s):  
Yi Lin ◽  
Xiaoming Zhou ◽  
Masato Kato ◽  
Daifei Liu ◽  
Sina Ghaemmaghami ◽  
...  

A methionine-rich low complexity (LC) domain is found within a C-terminal region of the TDP43 RNA-binding protein. Self-association of this domain leads to the formation of labile cross-β polymers and liquid-like droplets. Treatment with H2O2caused phenomena of methionine oxidation and droplet melting that were reversed upon exposure of the oxidized protein to methionine sulfoxide reductase enzymes. Morphological features of the cross-β polymers were revealed by H2O2-mediated footprinting. Equivalent TDP43 LC domain footprints were observed in polymerized hydrogels, liquid-like droplets, and living cells. The ability of H2O2to impede cross-β polymerization was abrogated by the prominent M337V amyotrophic lateral sclerosis-causing mutation. These observations may offer insight into the biological role of TDP43 in facilitating synapse-localized translation as well as aberrant aggregation of the protein in neurodegenerative diseases.


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