The platform consists of three modules, which are pre‐configured bioinformatic pipelines, cloud toolsets, and online omics' courses. The pre‐configured bioinformatic pipelines not only combine analytic tools for metagenomics, genomes, transcriptome, proteomics and metabolomics, but also provide users with powerful and convenient interactive analysis reports, which allow them to analyze and mine data independently. As a useful supplement to the bioinformatics pipelines, a wide range of cloud toolsets can further meet the needs of users for daily biological data processing, statistics, and visualization. The rich online courses of multi‐omics also provide a state‐of‐art platform to researchers in interactive communication and knowledge sharing.
Severe acute respiratory syndrome (SARS) was a worldwide epidemic caused by a coronavirus that has a cysteine protease (3CLpro) essential to its life cycle. Steady-state and pre-steady-state kinetic methods were used with highly active 3CLpro to characterize the reaction mechanism. We show that 3CLpro has mechanistic features common and disparate to the archetypical proteases papain and chymotrypsin. The kinetic mechanism for 3CLpro-mediated ester hydrolysis, including the individual rate constants, is consistent with a simple double displacement mechanism. The pre-steady-state burst rate was independent of ester substrate concentration indicating a high commitment to catalysis. When homologous peptidic amide and ester substrates were compared, a series of interesting observations emerged. Despite a 2000-fold difference in nonenzymatic reactivity, highly related amide and ester substrates were found to have similar kinetic parameters in both the steady-state and pre-steady-state. Steady-state solvent isotope effect (SIE) studies showed an inverse SIE for the amide but not ester substrates. Evaluation of the SIE in the pre-steady-state revealed normal SIEs for both amide and ester burst rates. Proton inventory (PI) studies on amide peptide hydrolysis were consistent with two proton-transfer reactions in the transition state while the ester data was consistent with a single proton-transfer reaction. Finally, the pH-inactivation profile of 3CLpro with iodoacetamide is indicative of an ion-pair mechanism. Taken together, the data are consistent with a 3CLpro mechanism that utilizes an "electrostatic" trigger to initiate the acylation reaction, a cysteine-histidine catalytic dyad ion pair, an enzyme-facilitated release of P1, and a general base-catalyzed deacylation reaction.
The checkpoint kinase Chk1 is an important mediator of cell cycle arrest following DNA damage. The 1.7 A resolution crystal structures of the human Chk1 kinase domain and its binary complex with an ATP analog has revealed an identical open kinase conformation. The secondary structure and side chain interactions stabilize the activation loop of Chk1 and enable kinase activity without phosphorylation of the catalytic domain. Molecular modeling of the interaction of a Cdc25C peptide with Chk1 has uncovered several conserved residues that are important for substrate selectivity. In addition, we found that the less conserved C-terminal region negatively impacts Chk1 kinase activity.
OBJECTIVE: The present study aimed to explore the expression profiles of circular RNAs (circRNAs) in glioblastoma multiforme (GBM) in an attempt to identify potential core genes in the pathogenesis of this tumor. METHODS: Differentially expressed circRNAs were screened between tumor tissues from five GBM patients and five normal brain samples using Illumina Hiseq. Bioinformatics analysis was used to analyze their potential function. CircBRAF was further detected in different WHO grades glioma tissues and normal brain tissues. Kaplan-Meier curves and multivariate Cox's analysis were used to analyze the association between circBRAF expression level and prognosis of glioma patients. RESULTS: A total of 1411 differentially expressed circRNAs were identified in GBM patients including 206 upregulated circRNAs and 1205 downregulated circRNAs. Differential expression of circRNAs was closely associated with the biological process and molecular function. The downregulated circRNAs were mainly associated with ErbB and Neurotrophin signaling pathways. Moreover, the expression level of circBRAF in normal brain tissues was significantly higher than that in glioma tissues (P < .001). CircBRAF was significantly lower in glioma patients with high pathological grade (WHO III & IV) than those with low grade (WHO I & II) (P < .001). Cox analysis revealed that high circBRAF expression was an independent biomarker for predicting good progression-free survival and overall survival in glioma patients (HR = 0.413, 95% CI 0.201-0.849; HR = 0.299, 95% CI 0.135-0.661; respectively). CONCLUSION: The present study identified a profile of dysregulated circRNAs in GBM. Bioinformatics analysis showed that dysregulated circRNAs might be associated with tumorigenesis and development of GBM. In addition, circBRAF could severe as a biomarker for predicting pathological grade and prognosis in glioma patients.
The guanosine triphosphatase-activating protein RLIP76 is overexpressed in many malignant tumor cells, but it is unclear if RLIP76 overexpression contributes to the high proliferative potential of glioma cells. We demonstrate that RLIP76 messenger RNA and protein expression are positively correlated with glioma grade and that higher RLIP76 expression correlates with shorter patient survival. Immunohistochemical staining revealed that RLIP76 expression was positively correlated with the expression of Ki-67, a biomarker for cell proliferation. Inhibition of RLIP76 expression in U87 and U251 glioma cell lines by stable transfection of a targeted siRNA suppressed anchorage-independent growth and enhanced apoptosis in vitro. Conversely, overexpression of RLIP76 in SW1088 and U251 cell lines enhanced proliferation and reduced apoptosis. Inhibition of RLIP76 in U251 cells also significantly suppressed tumorigenicity and induced apoptosis in an endotopic xenograft mouse model. Moreover, we demonstrate that knockdown of RLIP76 increases apoptosis in different human gliomas independently of p53 status. In addition, a constitutively active Rac1 reversed both the suppression of proliferation and the promotion of apoptosis induced by the RLIP76-targeted siRNA, indicating that RLIP76 is an upstream activator of Rac1. Rac1-mediated suppression of apoptosis and promotion of proliferation were dependent on intact c-jun N-terminal kinase (JNK) signaling. Furthermore, we demonstrate that RLIP76 promotes proliferation and suppresses glioma cell apoptosis through a mechanism independent of Rho-selective GTPase-activating protein. Instead, we found that the adenosine triphosphatase function of Rlip76 modulates Rac1 activity by regulating Rac1 protein ubiquitylation and degradation. These data demonstrate that RLIP76 may suppress apoptosis and promote the proliferation of glioma cells by direct adenosine triphosphate-dependent xenobiotic transport and by activating the Rac1-JNK signaling pathway. Inhibition of RLIP76 signaling is a potential treatment for malignant glioma.
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