scholarly journals Mechano-Biochemical Regulation of the C. elegans HMP1–HMP2 protein complex

2021 ◽  
Author(s):  
Shimin Le ◽  
Miao Yu ◽  
Sterling Martin ◽  
Jeff Hardin ◽  
Jie Yan
Keyword(s):  
Protein Complex ◽  
Mechanical Stability ◽  
Adherens Junction ◽  
Force Transmission ◽  
Physiological Level ◽  
C Elegans ◽  
Tissue Integrity ◽  
Environmental Perturbations ◽  
Domain Interactions ◽  
The Stability

The HMP1-HMP2 protein complex, a counterpart of α-catenin–β-catenin complex in C. elegans, mediates the tension transmission between HMR1 (cadherin) and actin cytoskeleton and serves as a critical mechanosensor at the cell–cell adherens junction. The complex has been shown to play critical roles in embryonic development and tissue integrity in C. elegans. The complex is subject to tension due to internal actomyosin contractility and external mechanical micro-environmental perturbations. However, how tension regulates the stability and interaction of HMP1–HMP2 complex has yet to be investigated. Here, we directly quantify the mechanical stability of the full-length HMP1 and its force-bearing modulation domains (M1-M3), and show that they unfold within physiological level of tension (pico-newton scale). The inter-domain interactions within the modulation domain leads to strong mechanical stabilization of M1 in HMP1, resulting in a significantly stronger force threshold to expose the buried vinculin binding site compared to the M1 domain in α-catenins. Moreover, we also quantify the mechanical stability of the inter-molecular HMP1–HMP2 interface and show that it is mechanically stable enough to support the tension-transmission and tension-sensing of the HMP1 modulation domains. Further, we show that single-residue phosphomimetic mutation (Y69E) on HMP2 weakens the mechanical stability of the HMP1–HMP2 interface and thus weakens the force-transmission molecular linkage and the associated mechanosensing functions. Together, these results provide a mechano-biochemical understanding of C. elegans HMP1–HMP2 protein complex’s roles in mechanotransduction.

An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Melt Spinning ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
Microstructural Analysis ◽  
Alloy System ◽  
Antimony Content ◽  
The Stability ◽  
Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 

Contribution of RNA Conformation to the Stability of a High-Affinity RNA−Protein Complex

2000 ◽  
Vol 122 (29) ◽  
pp. 7130-7131 ◽  
Author(s):  
Sarah J. Luchansky ◽  
Scott J. Nolan ◽  
Anne M. Baranger
Keyword(s):  
Protein Complex ◽  
High Affinity ◽  
Rna Conformation ◽  
The Stability

scholarly journals Treatment of Rheumatoid Arthritis with Traditional Chinese Medicine

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Wen-Yuan Lee ◽  
Hsin-Yi Chen ◽  
Kuan-Chung Chen ◽  
Calvin Yu-Chian Chen
Keyword(s):  
Rheumatoid Arthritis ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Protein Complex ◽  
Chronic Inflammatory Disease ◽  
Dynamics Simulation ◽  
Current Therapy ◽  
Potential Candidate ◽  
Interleukin 6 Receptor ◽  
The Stability

Rheumatoid arthritis (RA) is a chronic inflammatory disease that will affect quality of life and, working efficiency, and produce negative thoughts for patients. Current therapy of RA is treated with disease-modifying antirheumatic drugs (DMARDs). Although most of these treatment methods are effective, most patients still have a pleasant experience either due to poor efficacy or side effects or both. Interleukin-6 receptor (IL6R) is important in the pathogenesis of RA. In this study, we would like to detect the potential candidates which inhibit IL6R against RA from traditional Chinese medicine (TCM). We use TCM compounds from the TCM Database@Taiwan for virtually screening the potential IL6R inhibitors. The TCM candidate compound, calycosin, has potent binding affinity with IL6R protein. The molecular dynamics simulation was employed to validate the stability of interaction in the protein complex with calycosin. The analysis indicates that protein complex with calycosin is more stable. In addition, calycosin is known to be one of the components ofAngelica sinensis, which has been indicated to have an important role in the treatment of rheumatoid arthritis. Therefore, calycosin is a potential candidate as lead compounds for further study in drug development process with IL6R protein against rheumatoid arthritis.

scholarly journals Atypical Protein Kinase C Is Involved in the Evolutionarily Conserved Par Protein Complex and Plays a Critical Role in Establishing Epithelia-Specific Junctional Structures

2001 ◽  
Vol 152 (6) ◽  
pp. 1183-1196 ◽  
Author(s):  
Atsushi Suzuki ◽  
Tomoyuki Yamanaka ◽  
Tomonori Hirose ◽  
Naoyuki Manabe ◽  
Keiko Mizuno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Polarity ◽  
Protein Complex ◽  
Mdck Cells ◽  
Critical Role ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Surface Polarity ◽  
C Elegans ◽  
Evolutionarily Conserved

We have previously shown that during early Caenorhabditis elegans embryogenesis PKC-3, a C. elegans atypical PKC (aPKC), plays critical roles in the establishment of cell polarity required for subsequent asymmetric cleavage by interacting with PAR-3 [Tabuse, Y., Y. Izumi, F. Piano, K.J. Kemphues, J. Miwa, and S. Ohno. 1998. Development (Camb.). 125:3607–3614]. Together with the fact that aPKC and a mammalian PAR-3 homologue, aPKC-specific interacting protein (ASIP), colocalize at the tight junctions of polarized epithelial cells (Izumi, Y., H. Hirose, Y. Tamai, S.-I. Hirai, Y. Nagashima, T. Fujimoto, Y. Tabuse, K.J. Kemphues, and S. Ohno. 1998. J. Cell Biol. 143:95–106), this suggests a ubiquitous role for aPKC in establishing cell polarity in multicellular organisms. Here, we show that the overexpression of a dominant-negative mutant of aPKC (aPKCkn) in MDCK II cells causes mislocalization of ASIP/PAR-3. Immunocytochemical analyses, as well as measurements of paracellular diffusion of ions or nonionic solutes, demonstrate that the biogenesis of the tight junction structure itself is severely affected in aPKCkn-expressing cells. Furthermore, these cells show increased interdomain diffusion of fluorescent lipid and disruption of the polarized distribution of Na+,K+-ATPase, suggesting that epithelial cell surface polarity is severely impaired in these cells. On the other hand, we also found that aPKC associates not only with ASIP/PAR-3, but also with a mammalian homologue of C. elegans PAR-6 (mPAR-6), and thereby mediates the formation of an aPKC-ASIP/PAR-3–PAR-6 ternary complex that localizes to the apical junctional region of MDCK cells. These results indicate that aPKC is involved in the evolutionarily conserved PAR protein complex, and plays critical roles in the development of the junctional structures and apico-basal polarization of mammalian epithelial cells.

scholarly journals Exploración de la interacción entre la región 5´UTR del Sugarcane Mosaic Virus (SCMV) y proteínas del hospedero maíz

Respuestas ◽  
2017 ◽  
Vol 22 (1) ◽  
pp. 103
Author(s):  
Giovanni Chaves-Bedoya
Keyword(s):  
Mosaic Virus ◽  
Protein Complex ◽  
Sugarcane Mosaic Virus ◽  
Host Proteins ◽  
T7 Promoter ◽  
Viral Genomes ◽  
Uv Crosslinking ◽  
Maize Leaves ◽  
The Stability ◽  
Replicative Cycle

Resumen Antecedentes: El virus del mosaico de la caña de azúcar, SCMV (Potyviridae) es un miembro de la gran familia de virus de ARN de cadena positiva, sin una estructura CAP en su extremo 5´no traducido (5`UTR), pero con una proteína viral unida al genoma (VPg) y una cola poli A en su extremo 3´UTR. Se ha sugerido que proteínas del hospedero hacen un puente entre las regiones no traducidas virales 5´y 3´ para potenciar la traducción viral. Dado que las regiones no traducidas presentes en los genomas virales contienen elementos involucrados en la regulación de su ciclo replicativo, es importante analizar la interacción entre estas regiones y las proteínas virales o del hospedero para inferir su función. Objetivo: Determinar si existen proteínas del hospedero maíz que pudieran estar interactuando con la región 5´UTR de SCMV. Metodología: La región 5´UTR de SCMV se amplificó por PCR incluyendo la secuencia del promotor T7 en la secuencia del oligo 5´ UTR y se generaron sus transcritos marcados radiactivamente. Los transcritos marcados fueron entrecruzados con extractos proteicos de hojas de maíz sanas e infectadas. Resultados: Los resultados sugieren la presencia de una proteína putativa de interacción del hospedante maíz de aproximadamente 53kDa, con la región 5´UTR de SCMV. Conclusión: Los ensayos de entrecruzamiento, especificidad y estabilidad de los complejos ARN-proteína sugieren que en el hospedante maíz existe al menos una proteína que interactúa con la región 5´ UTR de SCMV.Palabras Clave: Complejo ARN-proteína, entrecruzamiento UV, fracción proteica, Potyvirus, VPg.Abstract Background: Sugarcane mosaic virus is a member of the great family of positive sense RNA viruses, without a CAP structure in its 5´UTR end, but with a viral protein attached to the genome (VPg) and a poli A tail in its 3´UTR end. It has been suggested that some host proteins make a bridge between the untranslated 5´and 3´ regions (UTRs) to enhance the canonical and/or non-canonical virus translation. Since the UTR regions present in the viral genomes have some elements involved in the regulation of their replicative cycle, it is important to analyze the interaction that may occur between these regions and the viral or host proteins to infer regarding its function. Objective: To identify proteins of the host maize that could be interacting with the 5´UTR region of SCMV. Methodology: 5´UTR region of SCMV was amplified by PCR including the sequence of the T7 promoter in the 5´oligo sequence. The transcripts were radioactively labeled. Labeled transcripts were crosslinked with proteins extracts from healthy and infected maize leaves. Results: The results suggest the presence of a 53 kDa putative protein interacting with the 5 ´UTR region of SCMV. Conclusion: Crosslinking essays, specificity and the stability of the RNA-protein complex suggest that in maize host there is at least one protein that interacts with the 5´UTR region of SCMV.Keywords: RNA-Protein complex, UV crosslinking, protein fraction, Potyvirus, VPg

Assembly of C. elegans apical junctions involves positioning and compaction by LET-413 and protein aggregation by the MAGUK protein DLG-1

2001 ◽  
Vol 114 (12) ◽  
pp. 2265-2277 ◽  
Author(s):  
Laura McMahon ◽  
Renaud Legouis ◽  
Jean-Luc Vonesch ◽  
Michel Labouesse
Keyword(s):  
Essential Gene ◽  
Critical Role ◽  
Septate Junction ◽  
C Elegans ◽  
Tissue Integrity ◽  
Discs Large ◽  
Genes Encoding ◽  
Strong Adhesion ◽  
Junctional Protein ◽  
Apical Junctions

Specialised subapical junctions play a critical role in maintaining epithelial cell polarity and tissue integrity, and provide a platform for intracellular signalling. Here we analyse the roles of C. elegans genes let-413 and dlg-1, a homologue of Drosophila lethal discs large, in the assembly of the C. elegans apical junction (CeAJ), and provide the first characterisation of this structure. We have identified dlg-1 as an essential gene in an RNA interference screen against C. elegans homologues of genes encoding proteins involved in tight or septate junction formation. We show that DLG-1 colocalises with the junctional protein JAM-1 at CeAJs in a unit distinct from HMP-1/α-catenin, and apical to the laterally localised LET-413. Loss of dlg-1 activity leads to JAM-1 mislocalisation and the disappearance of the electron-dense component of the CeAJs, but only mild adhesion and polarity defects. In contrast, loss of let-413 activity leads to the formation of basally extended discontinuous CeAJs and strong adhesion and polarity defects. Interestingly, in LET-413-deficient embryos, CeAJ markers are localised along the lateral membrane in a manner resembling that observed in wild-type embryos at the onset of epithelial differentiation. We conclude that the primary function of LET-413 is to correctly position CeAJ components at a discrete subapical position. Furthermore, we propose that DLG-1 is required to aggregate JAM-1 and other proteins forming the electron-dense CeAJ structure. Our data suggest that epithelial adhesion is maintained by several redundant systems in C. elegans.

SDC-3 coordinates the assembly of a dosage compensation complex on the nematode X chromosome

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1019-1031 ◽  
Author(s):  
T.L. Davis ◽  
B.J. Meyer
Keyword(s):  
Zinc Finger ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Protein Complex ◽  
Terminal Region ◽  
X Chromosomes ◽  
C Elegans ◽  
Amino Terminal ◽  
Zinc Finger Motifs ◽  
Specific Association

X chromosome expression in C. elegans is controlled by a chromosome-wide regulatory process called dosage compensation that specifically reduces by half the level of transcripts made from each hermaphrodite X chromosome. This process equalizes X expression between the sexes (XX hermaphrodites and XO males), despite their two-fold difference in X chromosome dose, and thereby prevents sex-specific lethality. Dosage compensation is achieved by a protein complex that associates with X in a sex-specific fashion to modulate gene expression. SDC-3, a protein that coordinately controls both sex determination and dosage compensation, activates dosage compensation by directing the dosage compensation protein complex to the hermaphrodite X chromosomes. We show that SDC-3 coordinates this assembly through its own sex-specific association with X. SDC-3 in turn requires other members of the dosage compensation gene hierarchy for its stability and its X localization. In addition, SDC-3 requires its own zinc finger motifs and an amino-terminal region for its X association. Our experiments suggest the possible involvement of zinc finger motifs in X chromosome recognition and the amino-terminal region in interactions with other dosage compensation proteins.

Temperature-Dependent Mechanical Stability of Retained Austenite in Thermomechanically Processed 3Mn Steel

2021 ◽  
Vol 1016 ◽  
pp. 762-767
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański
Keyword(s):  
Retained Austenite ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Trip Effect ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Static Tensile ◽  
The Stability ◽  
Backscatter Diffraction

The temperature-dependent mechanical stability of retained austenite in medium-Mn transformation induced plasticity 0.17C-3.3Mn-1.6Al-1.7Al-0.22Si-0.23Mo thermomechanically processed steel was investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) methods. Specimens were deformed up to rupture in static tensile tests in a temperature range 20–200°C. It was found that deformation temperature affects significantly the intensity of TRIP effect. In case of specimens deformed at temperatures higher than 60°C, a gradual temperature-related decrease in the stability of γ phase was noted. It indicates a progressive decrease of the significance of the TRIP effect and at the same time the growing importance of the thermally activated processes affecting a thermal stability of retained austenite.

scholarly journals Energetic dependencies dictate folding mechanism in a complex protein

2019 ◽  
Vol 116 (51) ◽  
pp. 25641-25648 ◽  
Author(s):  
Kaixian Liu ◽  
Xiuqi Chen ◽  
Christian M. Kaiser
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Large Scale ◽  
Elongation Factor ◽  
Multidomain Protein ◽  
Domain Interactions ◽  
The Stability ◽  
Domain Iii ◽  
And Function ◽  
Terminal Domains

Large proteins with multiple domains are thought to fold cotranslationally to minimize interdomain misfolding. Once folded, domains interact with each other through the formation of extensive interfaces that are important for protein stability and function. However, multidomain protein folding and the energetics of domain interactions remain poorly understood. In elongation factor G (EF-G), a highly conserved protein composed of 5 domains, the 2 N-terminal domains form a stably structured unit cotranslationally. Using single-molecule optical tweezers, we have defined the steps leading to fully folded EF-G. We find that the central domain III of EF-G is highly dynamic and does not fold upon emerging from the ribosome. Surprisingly, a large interface with the N-terminal domains does not contribute to the stability of domain III. Instead, it requires interactions with its folded C-terminal neighbors to be stably structured. Because of the directionality of protein synthesis, this energetic dependency of domain III on its C-terminal neighbors disrupts cotranslational folding and imposes a posttranslational mechanism on the folding of the C-terminal part of EF-G. As a consequence, unfolded domains accumulate during synthesis, leading to the extensive population of misfolded species that interfere with productive folding. Domain III flexibility enables large-scale conformational transitions that are part of the EF-G functional cycle during ribosome translocation. Our results suggest that energetic tuning of domain stabilities, which is likely crucial for EF-G function, complicates the folding of this large multidomain protein.

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