共查询到20条相似文献,搜索用时 328 毫秒
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《Biophysical journal》2022,121(13):2613-2623
Misfolding of TATA-box binding protein-associated factor 15 (TAF15) may cause neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS). Some mutations of prion-like domain (PrLD) have been detected in patients with sporadic ALS, suggesting the importance of TAF15-PrLD in ALS pathogenesis. Herein, combining experiments and molecular dynamics (MD) simulations, we investigated the influences of several TAF15-PrLD mutations on the amyloid fibril formation of TAF15-PrLD-extracted peptide segments, and identified an essential β-amyloid-forming segment from TAF15-PrLD. A pathogenic mutation T2 E71G resulted in significantly enhanced aggregation of the TAF15-PrLD segment T2 (Y56GQSQSGYSQSYGGYENQ73). In addition, the peptide T2 with a strong β-amyloid-forming tendency was able to induce the liquid to solid phase transition of TAF15-PrLD protein. Further study identified the SGYS motif as a critical segment that promoted the formation of amyloid fibrils, which maintained a stable β-sheet structure through intermolecular hydrogen bonds and π-π stacking interaction. This work provides a clue to elucidate the molecular pathogenic mechanism of TAF15-associated neurodegenerative diseases, and will direct drug development targeting TAF15. 相似文献
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Giovanni De Marco Annarosa Lomartire Giorgia Mandili Elisa Lupino Barbara Buccinnà Cristina Ramondetti Cristina Moglia Francesco Novelli Marco Piccinini Michael Mostert Maria Teresa Rinaudo Adriano Chiò Andrea Calvo 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2014
Accumulation of transactive response DNA binding protein (TDP-43) fragments in motor neurons is a post mortem hallmark of different neurodegenerative diseases. TDP-43 fragments are the products of the apoptotic caspases-3 and -7. Either excessive or insufficient cellular Ca2+ availability is associated with activation of apoptotic caspases. However, as far as we know, it is not described whether activation of caspases, due to restricted intracellular Ca2+, affects TDP-43 cleavage. Here we show that in various cell lineages with restricted Ca2+ availability, TDP-43 is initially cleaved by caspases-3 and -7 and then, also by caspases-6 and -8 once activated by caspase-3. Furthermore, we disclose the existence of a TDP-43 caspase-mediated fragment of 15 kDa, in addition to the well-known fragments of 35 and 25 kDa. Interestingly, with respect to the other two fragments this novel fragment is the major product of caspase activity on murine TDP-43 whereas in human cell lines the opposite occurs. This outcome should be considered when murine models are used to investigate TDP-43 proteinopathies. 相似文献
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Julián Pardo Eva Ma Gálvez Aulikki Koskinen Markus M. Simon Mario Lobigs Matthias Regner Arno Müllbacher 《PloS one》2009,4(10)
Background
Ectromelia virus is a natural mouse pathogen, causing mousepox. The cytotoxic T (Tc) cell granule serine-protease, granzyme B, is important for its control, but the underlying mechanism is unknown. Using ex vivo virus immune Tc cells, we have previously shown that granzyme B is able to activate several independent pro-apoptotic pathways, including those mediated by Bid/Bak/Bax and caspases-3/-7, in target cells pulsed with Tc cell determinants.Methods and Findings
Here we analysed the physiological relevance of those pro-apoptotic pathways in ectromelia infection, by incubating ectromelia-immune ex vivo Tc cells from granzyme A deficient (GzmB+ Tc cells) or granzyme A and granzyme B deficient (GzmA×B−/− Tc cell) mice with ectromelia-infected target cells. We found that gzmB-induced apoptosis was totally blocked in ectromelia infected or peptide pulsed cells lacking caspases-3/-7. However ectromelia inhibited only partially apoptosis in cells deficient for Bid/Bak/Bax and not at all when both pathways were operative suggesting that the virus is able to interfere with apoptosis induced by gzmB in case not all pathways are activated. Importantly, inhibition of viral replication in vitro, as seen with wild type cells, was not affected by the lack of Bid/Bak/Bax but was significantly reduced in caspase-3/-7-deficient cells. Both caspase dependent processes were strictly dependent on gzmB, since Tc cells, lacking both gzms, neither induced apoptosis nor reduced viral titers.Significance
Out findings present the first evidence on the biological importance of the independent gzmB-inducible pro-apoptotic pathways in a physiological relevant virus infection model. 相似文献12.
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Nuri Yun Young Mook Lee Chiho Kim Hirohiko Shibayama Akira Tanimura Yuri Hamanaka Yuzuru Kanakura Il-Seon Park Areum Jo Joo-Ho Shin Chung Ju Won-Ki Kim Young J. Oh 《The Journal of biological chemistry》2014,289(32):22183-22195
Activated caspases play a central role in the execution of apoptosis by cleaving endogenous substrates. Here, we developed a high throughput screening method to identify novel substrates for caspase-3 in a neuronal cell line. Critical steps in our strategy consist of two-dimensional electrophoresis-based protein separation and in vitro caspase-3 incubation of immobilized proteins to sort out direct substrates. Among 46 putative substrates identified in MN9D neuronal cells, we further evaluated whether caspase-3-mediated cleavage of anamorsin, a recently recognized cell death-defying factor in hematopoiesis, is a general feature of apoptosis. In vitro and cell-based cleavage assays indicated that anamorsin was specifically cleaved by caspase-3 but not by other caspases, generating 25- and 10-kDa fragments. Thus, in apoptosis of neuronal and non-neuronal cells induced by various stimuli including staurosporine, etoposide, or 6-hydroxydopamine, the cleavage of anamorsin was found to be blocked in the presence of caspase inhibitor. Among four tetrapeptide consensus DXXD motifs existing in anamorsin, we mapped a specific cleavage site for caspase-3 at DSVD209↓L. Intriguingly, the 25-kDa cleaved fragment of anamorsin was also detected in post-mortem brains of Alzheimer and Parkinson disease patients. Although the RNA interference-mediated knockdown of anamorsin rendered neuronal cells more vulnerable to staurosporine treatment, reintroduction of full-length anamorsin into an anamorsin knock-out stromal cell line made cells resistant to staurosporine-induced caspase activation, indicating the antiapoptotic function of anamorsin. Taken together, our approach seems to be effective to identify novel substrates for caspases and has the potential to provide meaningful insights into newly identified substrates involved in neurodegenerative processes. 相似文献
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Magdalena Wejda Francis Impens Nozomi Takahashi Petra Van Damme Kris Gevaert Peter Vandenabeele 《The Journal of biological chemistry》2012,287(41):33983-33995
Caspase-2 is considered an initiator caspase because its long prodomain contains a CARD domain that allows its recruitment and activation in several complexes by homotypic death domain-fold interactions. Because little is known about the function and specificity of caspase-2 and its physiological substrates, we compared the cleavage specificity profile of recombinant human caspase-2 with those of caspase-3 and -7 by analyzing cell lysates using N-terminal COmbined FRActional DIagonal Chromatography (COFRADIC). Substrate analysis of the 68 cleavage sites identified in 61 proteins revealed that the protease specificities of human caspases-2, -3, and -7 largely overlap, revealing the DEVD↓G consensus cleavage sequence. We confirmed that Asp563 in eukaryotic translation initiation factor 4B (eIF4B) is a cleavage site preferred by caspase-2 not only in COFRADIC setup but also upon co-expression in HEK 293T cells. These results demonstrate that activated human caspase-2 shares remarkably overlapping protease specificity with the prototype apoptotic executioner caspases-3 and -7, suggesting that caspase-2 could function as a proapoptotic caspase once released from the activating complex. 相似文献
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E D Crawford J E Seaman A E Barber II D C David P C Babbitt A L Burlingame J A Wells 《Cell death and differentiation》2012,19(12):2040-2048
Caspases, cysteine proteases with aspartate specificity, are key players in programmed cell death across the metazoan lineage. Hundreds of apoptotic caspase substrates have been identified in human cells. Some have been extensively characterized, revealing key functional nodes for apoptosis signaling and important drug targets in cancer. But the functional significance of most cuts remains mysterious. We set out to better understand the importance of caspase cleavage specificity in apoptosis by asking which cleavage events are conserved across metazoan model species. Using N-terminal labeling followed by mass spectrometry, we identified 257 caspase cleavage sites in mouse, 130 in Drosophila, and 50 in Caenorhabditis elegans. The large majority of the caspase cut sites identified in mouse proteins were found conserved in human orthologs. However, while many of the same proteins targeted in the more distantly related species were cleaved in human orthologs, the exact sites were often different. Furthermore, similar functional pathways are targeted by caspases in all four species. Our data suggest a model for the evolution of apoptotic caspase specificity that highlights the hierarchical importance of functional pathways over specific proteins, and proteins over their specific cleavage site motifs. 相似文献
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Bin Yu Min Gong Zhisong He Yi-Gang Wang Ronald W. Millard Muhammad Ashraf Meifeng Xu 《The international journal of biochemistry & cell biology》2013,45(12):2724-2735
We reported previously that pre-programming mesenchymal stem cells with the GATA-4 gene increases significantly cell survival in an ischemic environment. In this study, we tested whether regulation of microRNAs and their target proteins was associated with the cytoprotective effects of GATA-4.Methods and resultsMesenchymal stem cells were harvested from adult rat bone marrow and transduced with GATA-4 (MSCGATA-4) using the murine stem cell virus retroviral expression system. Cells transfected with empty vector (MSCNull) were used as controls. Quantitative real-time PCR data showed that the expression levels of miR-15 family members (miR-15b, miR-16, and miR-195) were significantly down-regulated in MSCGATA-4. The protein expression of Bcl-w (Bcl-2-like-2), an anti-apoptotic Bcl-2 family protein, was increased in MSCGATA-4. Hypoxic culture (low glucose and low oxygen) induced the release of lactate dehydrogenase from mesenchymal stem cells and reduced cell survival. Compared to MSCNull, MSCGATA-4 showed less lactate dehydrogenase release and greater cell survival following 72 h hypoxia exposure. The mitochondrial membrane potential, detected with the dye JC-1, was well maintained, and mitochondrial membrane permeability, expressed as caspase 3 and 7 activities in response to the ischemic environment was lower in MSCGATA-4. Moreover, transfection with miR-195 significantly down-regulated Bcl-w expression in mesenchymal stem cells through a binding site in the 3′-UTR of the Bcl-w mRNA and reduced mesenchymal stem cell resistance to ischemic injury.ConclusionsThe overexpression of GATA-4 in mesenchymal stem cells down-regulates miR-15 family members, causing increased resistance to ischemia through the up-regulation of anti-apoptotic proteins in the Bcl-2 family. 相似文献
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Petros Papadopoulos Laura Gutiérrez Jeroen Demmers Elisabeth Scheer Farzin Pourfarzad Dimitris N. Papageorgiou Elena Karkoulia John Strouboulis Harmen J. G. van de Werken Reinier van der Linden Peter Vandenberghe Dick H. W. Dekkers Sjaak Philipsen Frank Grosveld Làszlò Tora 《Molecular and cellular biology》2015,35(12):2103-2118