Hydrogen-bond formation of the residue in H-loop of the nucleotide binding domain 2 with the ATP in this site and/or other residues of multidrug resistance protein MRP1 plays a crucial role during ATP-dependent solute transport

AbstractMRP1 couples ATP binding/hydrolysis to solute transport. We have shown that ATP binding to nucleotide-binding-domain 1 (NBD1) plays a regulatory role whereas ATP hydrolysis at NBD2 plays a crucial role in ATP-dependent solute transport. However, how ATP is hydrolyzed at NBD2 is not well elucidated. To partially address this question, we have mutated the histidine residue in H-loop of MRP1 to either a residue that prevents the formation of hydrogen-bonds with ATP and other residues in MRP1 or a residue that may potentially form these hydrogen-bonds. Interestingly, substitution of H827 in NBD1 with residues that prevented formation of these hydrogen-bonds had no effect on the ATP-dependent solute transport whereas corresponding mutations in NBD2 almost abolished the ATP-dependent solute transport completely. In contrast, substitutions of H1486 in H-loop of NBD2 with residues that might potentially form these hydrogen-bonds exerted either full function or partial function, implying that hydrogen-bond formation between the residue at 1486 and the γ-phosphate of the bound ATP and/or other residues, such as putative catalytic base E1455, together with S769, G771, T1329 and K1333, etc., holds all the components necessary for ATP binding/hydrolysis firmly so that the activated water molecule can efficiently hydrolyze the bound ATP at NBD2

Uncertainty Quantification Models For Micro-Scale Squeeze-Film Damping

Two squeeze-film gas damping models are proposed to quantify uncertainties associated with the gap size and the ambient pressure. Modeling of gas damping has become a subject of increased interest in recent years due to its importance in micro-electro-mechanical systems (MEMS). In addition to the need for gas damping models for design of MEMS with movable micro-structures, knowledge of parameter dependence in gas damping contributes to the understanding of device-level reliability. In this work, two damping models quantifying the uncertainty in parameters are generated based on rarefied flow simulations. One is a generalized polynomial chaos (gPC) model, which is a general strategy for uncertainty quantification, and the other is a compact model developed specifically for this problem in an early work. Convergence and statistical analysis have been conducted to verify both models. By taking the gap size and ambient pressure as random fields with known probability distribution functions (PDF), the output PDF for the damping coefficient can be obtained. The first four central moments are used in comparisons of the resulting non-parametric distributions. A good agreement has been found, within 1%, for the relative difference for damping coefficient mean values. In study of geometric uncertainty, it is found that the average damping coefficient can deviate up to 13% from the damping coefficient corresponding to the average gap size. The difference is significant at the nonlinear region where the flow is in slip or transitional rarefied regimes

Potential sites of CFTR activation by tyrosine kinases

The CFTR chloride channel is tightly regulated by phosphorylation at multiple serine residues. Recently it has been proposed that its activity is also regulated by tyrosine kinases, however the tyrosine phosphorylation sites remain to be identified. In this study we examined 2 candidate tyrosine residues near the boundary between the first nucleotide binding domain and the R domain, a region which is important for channel function but devoid of PKA consensus sequences. Mutating tyrosines at positions 625 and 627 dramatically reduced responses to Src or Pyk2 without altering the activation by PKA, suggesting they may contribute to CFTR regulation

Misassembled mutant F508 CFTR in the distal secretory pathway alters cellular lipid trafficking

Most patients with cystic fibrosis (CF) have a single codon deletion (DeltaF508) in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) that impairs assembly of the multidomain glycoprotein. The mutant protein escapes endoplasmic reticulum (ER) quality control at low temperature, but is rapidly cleared from the distal secretory pathway and degraded in lysosomes. CF cells accumulate free cholesterol similar to Niemann-Pick disease type C cells. We show that this lipid alteration is caused by the presence of misassembled mutant CFTR proteins, including DeltaF508, in the distal secretory pathway rather than the absence of functional CFTR. By contrast, cholesterol distribution is not changed by either D572N CFTR, which does not mature even at low temperature, or G551D, which is processed normally but is inactive. On expression of the DeltaF508 mutant, cholesterol and glycosphingolipids accumulate in punctate endosomal structures and cholesterol esters are reduced, indicating a block in the translocation of cholesterol to the ER for esterification. This is overcome by Rab9 overexpression, resulting in clearance of accumulating intracellular cholesterol. Similar but less pronounced alterations in intracellular cholesterol distribution are observed on expression of a temperature-rescued mutant variant of the related ATP-binding cassette (ABC) protein multidrug resistance-associated protein 1 (MRP1). Thus, on escape from ER quality control, misassembled mutants of CFTR and MRP1 impair lipid homeostasis in endocytic compartments

Digital economy: an effective path for promoting residents' health in China

The primary prerequisite for socioeconomic growth is good health, hence promoting residents' health is a vital objective of public policies. It is yet up for debate whether or not the digital economy (DE), which will be crucial to future economic growth, will eventually result in improvements in residents' health. Utilizing the China Family Panel Studies (CFPS) data in 2020, we explore how the DE affects residents' health. The findings reveal that residents' health is greatly enhanced by the DE. The eastern region sees a more dramatic improvement in residents' health as a result of the DE. Additionally, the DE can improve residents' health through the promotion of regional green development. The study's findings add to our knowledge of how the DE impacts residents' health while also offering recommendations for achieving universal health

Construction of a cDNA library and preliminary analysis of the expressed sequence tags of the earthworm Eisenia fetida (Savigny, 1826)

Earthworms are useful indicator organisms of soil health and Eisenia fetida have been extensively used as test organisms in ecotoxicological studies. In order to gain insight into the gene expression profiles associated with physiological functions of earthworms, a full‑length enriched cDNA library of the Eisenia fetida genome was successfully constructed using Switching Mechanism at 5\u27End of RNA Template technology. Construction of a cDNA library and analysis of Expressed Sequence Tags (ESTs) are efficient approaches for collecting genomic information and identifying genes important for a given biological process. Furthermore, analysis of the expression abundance of ESTs was performed with the aim of providing genetic and transcriptomic information on the development and regenerative process of earthworms. Phrep and Crossmatch were used to process EST data and a total of 1,140 high‑quality EST sequences were determined by sequencing random cDNA clones from the library. Clustering analysis of sequences revealed a total of 593 unique sequences including 225 contiguous and 368 singleton sequences. Basic Local Alignment Search Tool analysis against the Kyoto Encyclopedia of Genes and Genomes database resulted in 593 significant hits (P‑value \u3c1x10‑8), of which 168 were annotated through Gene Ontology analysis. The STRING database was used to determine relationships among the 168 ESTs, identifying associated genes involved in protein‑protein interactions and gene expression regulation. Based on nucleic acid and protein sequence homology, the mutual relationships between 287 genes could be obtained, which identified a portion of the ESTs as known genes. The present study reports on the construction of a high‑quality cDNA library representative of adult earthworms, on a preliminary analysis of ESTs and on a putative functional analysis of ESTs. The present study is expected to enhance our understanding of the molecular basis underlying the biological development of earthworms

Clinical Value of Machine Learning in the Automated Detection of Focal Cortical Dysplasia Using Quantitative Multimodal Surface-Based Features

Objective: To automatically detect focal cortical dysplasia (FCD) lesion by combining quantitative multimodal surface-based features with machine learning and to assess its clinical value.Methods: Neuroimaging data and clinical information for 74 participants (40 with histologically proven FCD type II) was retrospectively included. The morphology, intensity and function-based features characterizing FCD lesions were calculated vertex-wise on each cortical surface and fed to an artificial neural network. The classifier performance was quantitatively and qualitatively assessed by performing statistical analysis and conventional visual analysis.Results: The accuracy, sensitivity, specificity of the neural network classifier based on multimodal surface-based features were 70.5%, 70.0%, and 69.9%, respectively, which outperformed the unimodal classifier. There was no significant difference in the detection rate of FCD subtypes (Pearson’s Chi-Square = 0.001, p = 0.970). Cohen’s kappa score between automated detection outcomes and post-surgical resection region was 0.385 (considered as fair).Conclusion: Automated machine learning with multimodal surface features can provide objective and intelligent detection of FCD lesion in pre-surgical evaluation and can assist the surgical strategy. Furthermore, the optimal parameters, appropriate surface features and efficient algorithm are worth exploring

Charge-changing cross section measurements of 300 MeV/nucleon 28^{28}Si on carbon and data analysis

Charge-changing cross section ($\sigma_{\text{cc}}$) measurements via the transmission method have made important progress recently aiming to determine the charge radii of exotic nuclei. In this work, we report a new $\sigma_{\text{cc}}$ measurement of 304(9) MeV/nucleon $^{28}$Si on carbon at the second Radioactive Ion Beam Line in Lanzhou (RIBLL2) and describe the data analysis procedure in detail. This procedure is essential to evaluate the systematic uncertainty in the transmission method. The determined $\sigma_{\mathrm{cc}}$ of 1125(11) mb is found to be consistent with the existing data at similar energies. The present work will serve as a reference in the $\sigma_{\text{cc}}$ determinations at RIBLL2.Comment: 9 pages, 13 figures, to be published in Chinese Physics