Molecular Chaperone
Dotaz
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- MeSH
- biofyzika MeSH
- fyziologie buňky MeSH
- molekulární chaperony fyziologie klasifikace MeSH
- sbalování proteinů fyziologie MeSH
- Publikační typ
- přehledy MeSH
Kinesin-like calmodulin-binding protein (KCBP) is a unique kinesin with half kinesin and half myosin, with kinesin motor domain at C-terminus and myosin tail homology region 4 (MyTH4) and band 4.1, ezrin, radixin, moesin (FERM) domains at N-terminus. The special structure endows KCBP multi-intracellular functions, including cell division, trichome morphogenesis in plants, and flagellar function in algae. However, little is known about the molecular mechanism underlying these functions. Here, we identified a molecular chaperone Hsp90 as a novel binding partner with KCBP in Dunaliella salina using a yeast two-hybrid screen. Further analysis showed that Hsp90 interacted with both the N-terminal and C-terminal of DsKCBP. Since Hsp90 was involved in the stability and proteolytic turnover of numerous proteins, whether Hsp90 regulated the degradation of DsKCBP was investigated. Our results showed that both Hsp90 and DsKCBP presented in the purified proteasome, and the interaction of DsKCBP-Hsp90 was inhibited upon Hsp90 inhibitor geldanamycin treatment. The level of DsKCBP proteins was diminished remarkably indicating that the disassociation of DsKCBP from Hsp90 accelerated the degradation of the former. Furthermore, immunofluorescence results showed that the localization of DsKCBP at basal body and flagella was disappeared by Hsp90 inhibition. The increased mRNA level of DsKCBP during flagellar assembly was not obvious by geldanamycin treatment. These data provided evidence that Hsp90 protected DsKCBP from degradation by proteasome and was involved in the role of DsKCBP in flagellar assembly.
- MeSH
- glykoproteiny MeSH
- haptoglobiny MeSH
- katalasa MeSH
- krystaliny MeSH
- krystalografie rentgenová MeSH
- lidé MeSH
- molekulární chaperony MeSH
- proteiny teplotního šoku MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
N-terminal P23H opsin mutation accounts for most of retinitis pigmentosa (RP) cases. P23H functions and folding can be rescued by small chaperone ligands, which contributes to validate mutant opsin as a suitable target for pharmacological treatment of RP. However, the lack of structural details on P23H mutant opsin strongly impairs drug design, and new chemotypes of effective chaperones of P23H opsin are in high demand. Here, a computational-boosted workflow combining homology modeling with molecular dynamics (MD) simulations and virtual screening was used to select putative P23H opsin chaperones among different libraries through a structure-based approach. In vitro studies corroborated the reliability of the structural model generated in this work and identified a number of novel chemotypes of safe and effective chaperones able to promote P23H opsin trafficking to the outer cell membrane.
- MeSH
- lidé MeSH
- molekulární chaperony genetika metabolismus terapeutické užití MeSH
- opsiny * genetika MeSH
- reprodukovatelnost výsledků MeSH
- retinopathia pigmentosa * farmakoterapie genetika metabolismus MeSH
- tyčinkové opsiny chemie genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Classical homocystinuria is caused by mutations in the cystathionine β-synthase (CBS) gene. Previous experiments in bacterial and yeast cells showed that many mutant CBS enzymes misfold and that chemical chaperones enable proper folding of a number of mutations. In the present study, we tested the extent of misfolding of 27 CBS mutations previously tested in E. coli under the more folding-permissive conditions of mammalian CHO-K1 cells and the ability of chaperones to rescue the conformation of these mutations. Expression of mutations in mammalian cells increased the median activity 16-fold and the amount of tetramers 3.2-fold compared with expression in bacteria. Subsequently, we tested the responses of seven selected mutations to three compounds with chaperone-like activity. Aminooxyacetic acid and 4-phenylbutyric acid exhibited only a weak effect. In contrast, heme arginate substantially increased the formation of mutant CBS protein tetramers (up to sixfold) and rescued catalytic activity (up to ninefold) of five out of seven mutations (p.A114V, p.K102N, p.R125Q, p.R266K, and p.R369C). The greatest effect of heme arginate was observed for the mutation p.R125Q, which is non-responsive to in vivo treatment with vitamin B(6). Moreover, the heme responsiveness of the p.R125Q mutation was confirmed in fibroblasts derived from a patient homozygous for this genetic variant. Based on these data, we propose that a distinct group of heme-responsive CBS mutations may exist and that the heme pocket of CBS may become an important target for designing novel therapies for homocystinuria.
- MeSH
- arginin farmakologie MeSH
- CHO buňky MeSH
- Cricetulus MeSH
- cystathionin-beta-synthasa genetika metabolismus MeSH
- fenotyp MeSH
- fibroblasty účinky léků enzymologie MeSH
- genetická predispozice k nemoci MeSH
- hem farmakologie MeSH
- homocystinurie diagnóza farmakoterapie enzymologie genetika MeSH
- homozygot MeSH
- katalytická doména MeSH
- konformace proteinů MeSH
- lidé MeSH
- molekulární chaperony farmakologie MeSH
- molekulární modely MeSH
- mutace * MeSH
- poruchy proteostázy diagnóza farmakoterapie enzymologie genetika MeSH
- sbalování proteinů MeSH
- substrátová specifita MeSH
- transfekce MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- práce podpořená grantem MeSH
Molekulární chaperony (heat-shock proteiny, Hsps) jsou proteiny, které udržují intracelulární homeostázu skládáním a stabilizací konformace jiných proteinů. Díky schopnosti chránit proteom před špatně složenými a agregovanými proteiny jsou chaperony nezbytné pro přežití buněk vystavených stresu. Kromě základní funkce v udržování buněčné homeostázy a ochraně před vnějšími stresovými faktory hrají některé molekulární chaperony důležitou roli i při transformaci nádorové buňky. Zvýšená hladina chaperonů byla detekována u mnoha solidních nádorů a hematopoetických malignit. Nárůst aktivity chaperonů v nádorových buňkách odráží jejich schopnost kompenzovat stresové podmínky způsobené hypoxií, zvýšenou proteosyntézou a přítomností mutantních a potenciálně nestabilních proteinů. Chaperony navíc umožňují nádorovým buňkám tolerovat genetické změny stabilizováním terciární struktury mutantních proteinů – typicky onkoproteinů –, které by jinak byly pro buňku letální. Z tohoto pohledu chaperony zprostředkovávají fenotypové vyjádření onkogeních mutací a přispívají k získání všech základních znaků nádorové buňky. Kvůli jejich nezbytné funkci v nádorech ovlivňující současně několik esenciálních onkogenních drah se chaperony staly atraktivním cílem nádorové terapie. Klíčova slova: molekulární chaperony – ko-chaperony – Hsp90 – nádorové onemocnění
Molecular chaperones (heat-shock proteins, Hsps) are proteins that maintain intracellular homeostasis through folding and stabilisation of the conformation of other proteins. Molecular chaperones are critical for survival of cells that undergo cellular stress due to their ability to guard the proteome against misfolded proteins and aggregation. In addition to their canonical role in basic cellular homeostasis and protection against external stress, several molecular chaperones play a fundamental role in malignant cell transformation. The level of molecular chaperones is increased in many solid tumours and haematological malignancies. The increased activity of Hsps in cancer cells reflects the ability of chaperones to compensate for stress caused by hypoxia, increased protein turnover and the presence of numerous mutated and potentially unstable proteins. In addition, chaperones allow tumour cells to tolerate genetic alterations by stabilising tertiary structure of mutated unstable proteins – typically oncoproteins that would otherwise be lethal. From this perspective, chaperones mediate the phenotypic expression of oncogenic mutations and contribute to all the hallmarks of cancer cells. Due to their indispensable roles for cancer cells, chaperones became an attractive group of targets for novel cancer therapies affecting several essential oncogenic pathways simultaneously.
- Klíčová slova
- ko-chaperony, nádorové onemocnění, Hsp90, geldanamycin,
- MeSH
- benzochinony farmakologie terapeutické užití MeSH
- DNA vazebné proteiny terapeutické užití MeSH
- lidé MeSH
- makrocyklické laktamy farmakologie terapeutické užití MeSH
- molekulární chaperony * MeSH
- nádorová transformace buněk * MeSH
- nádory etiologie farmakoterapie MeSH
- proteiny tepelného šoku HSP90 MeSH
- proteiny teplotního šoku * MeSH
- transkripční faktory terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Frontiers in molecular biology
1st ed. xx, 281 s. : il.
- MeSH
- molekulární biologie MeSH
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biologie
Rotavirus genomes are distributed between 11 distinct RNA molecules, all of which must be selectively copackaged during virus assembly. This likely occurs through sequence-specific RNA interactions facilitated by the RNA chaperone NSP2. Here, we report that NSP2 autoregulates its chaperone activity through its C-terminal region (CTR) that promotes RNA-RNA interactions by limiting its helix-unwinding activity. Unexpectedly, structural proteomics data revealed that the CTR does not directly interact with RNA, while accelerating RNA release from NSP2. Cryo-electron microscopy reconstructions of an NSP2-RNA complex reveal a highly conserved acidic patch on the CTR, which is poised toward the bound RNA. Virus replication was abrogated by charge-disrupting mutations within the acidic patch but completely restored by charge-preserving mutations. Mechanistic similarities between NSP2 and the unrelated bacterial RNA chaperone Hfq suggest that accelerating RNA dissociation while promoting intermolecular RNA interactions may be a widespread strategy of RNA chaperone recycling.
- MeSH
- elektronová kryomikroskopie MeSH
- genom virový genetika MeSH
- molekulární chaperony metabolismus MeSH
- molekulární modely MeSH
- proteiny vázající RNA metabolismus MeSH
- ribonukleoproteiny metabolismus MeSH
- RNA virová genetika MeSH
- Rotavirus genetika růst a vývoj metabolismus MeSH
- sbalování RNA genetika MeSH
- virové nestrukturální proteiny metabolismus MeSH
- zabalení virového genomu genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
An increasing number of human diseases has been shown to be linked to aggregation and amyloid formation by intrinsically disordered proteins (IDPs). Amylin, amyloid-β, and α-synuclein are, indeed, involved in type-II diabetes, Alzheimer's, and Parkinson's, respectively. Despite the correlation of the toxicity of these proteins at early aggregation stages with membrane damage, the molecular events underlying the process is quite complex to understand. In this study, we demonstrate the crucial role of free lipids in the formation of lipid-protein complex, which enables an easy membrane insertion for amylin, amyloid-β, and α-synuclein. Experimental results from a variety of biophysical methods and molecular dynamics results reveal that this common molecular pathway in membrane poration is shared by amyloidogenic (amylin, amyloid-β, and α-synuclein) and nonamyloidogenic (rat IAPP, β-synuclein) proteins. Based on these results, we propose a "lipid-chaperone" hypothesis as a unifying framework for protein-membrane poration.
- MeSH
- alfa-synuklein MeSH
- amylin MeSH
- amyloid MeSH
- amyloidogenní proteiny MeSH
- krysa rodu rattus MeSH
- lipidy MeSH
- vnitřně neuspořádané proteiny * MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
