Category Archives: Israel Journal of Chemistry

Engineered RNA‐binding Proteins: Studying and Controlling RNA Regulation

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Engineered RNA-binding Proteins: Studying and Controlling RNA Regulation


Abstract

The complexity of eukaryotic organisms is intricately tied to transcriptome-level processes, notably alternative splicing and the precise modulation of gene expression through a sophisticated interplay involving RNA-binding protein (RBP) networks and their RNA targets. Recent advances in our understanding of the molecular pathways responsible for this control have paved the way for the development of tools capable of steering and managing RNA regulation and gene expression. The fusion between a rapidly developing understanding of endogenous RNA regulation and the burgeoning capabilities of CRISPR-Cas and other programmable RBP platforms has given rise to an exciting frontier in engineered RNA regulators. This review offers an overview of the existing toolkit for constructing synthetic RNA regulators using programmable RBPs and effector domains, capable of altering RNA sequence composition or fate, and explores their diverse applications in both basic research and therapeutic contexts.

Structure‐Activity Relationships of 2‐(Arylthio)benzoic Acid FTO Inhibitors

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Structure-Activity Relationships of 2-(Arylthio)benzoic Acid FTO Inhibitors


Abstract

The biological role of the fat mass and obesity-associated protein (FTO) in the initiation and progress of acute myeloid leukemia (AML) has been elucidated, and several representative FTO inhibitors can markedly suppress the proliferation of AML cells. We previously developed FTO inhibitors including FB23. In this study, we adopted bioisosteric replacement of the intramolecular hydrogen bond in FB23 with a sulfur-oxygen interaction to generate a series of 2-(arylthio)benzoic acid FTO inhibitors and established their structure-activity relationships. Compound 8c was the most potent 2-(arylthio)benzoic acid FTO inhibitor with an IC50 value of 0.3±0.1 μM, which was comparable with that of FB23 in vitro. To enhance the antiproliferative effects in AML cell lines, we applied a prodrug strategy and prepared some esters. 7l, the methyl ester of 8l, exerted a superior inhibitory effect on a panel of AML cancer cell lines. Additionally, 7l treatment notably increased global m6A abundance in AML cells. Collectively, our data suggest that 2-(arylthio)benzoic acid may be a new lead compound for inhibition of FTO, and the prodrug analog exhibit potential in the treatment of AML.

Recent Advance in the Study on 5‐Formylcytosine (f5C) RNA Modification

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Recent Advance in the Study on 5-Formylcytosine (f5C) RNA Modification


Abstract

The widespread involvement of 5-formylcytosine f5C RNA in gene function regulation and its impact on crucial life processes like cell differentiation, embryonic development, and disease development underscores the significance of detecting this specific base modification. This detection holds great importance for basic epigenetics research and the early diagnosis and pathogenesis research of various diseases. This review aims to summarize recent research progress in f5C detection methods using selective chemical labeling, with the hope of aiding future research endeavors.

Protein Glycosylation Patterns Shaped By the IRE1‐XBP1s Arm of the Unfolded Protein Response

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Protein Glycosylation Patterns Shaped By the IRE1-XBP1s Arm of the Unfolded Protein Response


Abstract

The unfolded protein response (UPR) is a sensing and signaling pathway that surveys the endoplasmic reticulum (ER) for protein folding challenges and responds whenever issues are detected. UPR activation leads to upregulation of secretory pathway chaperones and quality control factors, as well as reduces the nascent protein load on the ER, thereby restoring and maintaining proteostasis. This paradigm-defining view of the role of the UPR is accurate, but it elides additional key functions of the UPR in cell biology. In particular, recent work has revealed that the UPR can shape the structure and function of N- and O-glycans installed on ER client proteins. This crosstalk between the UPR's reaction to protein misfolding and the regulation of glycosylation remains insufficiently understood. Still, emerging evidence makes it clear that the UPR, and particularly the IRE1-XBP1s arm of the UPR, may be a central regulator of protein glycosylation, with important biological consequences. In this review, we discuss the crosstalk between proteostasis, the UPR, and glycosylation, present progress towards understanding biological functions of this crosstalk, and examine potential roles in diseases such as cancer.

Ising spins on frustrated bronze‐mean hexagonal quasicrystal

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Ising spins on frustrated bronze-mean hexagonal quasicrystal


Abstract

We investigate the Ising model on the Bronze-mean hexagonal quasicrystal (BMH QC), an aperiodic tiling with geometric frustration. Our extensive Monte Carlo simulations explore the model's rich phase diagram, revealing six distinct phases with diverse magnetic properties and degrees of frustration. We uncover exotic spin glass phases, signaled by the replica symmetry breaking and slow relaxation dynamics. We shed light on the intriguing magnetic properties of frustrated quasicrystals and open new avenues for studying exotic phases in condensed matter physics.

Nanopore Direct RNA Sequencing for Modified Uridine Nucleotides Yields Signals Dependent on the Physical Properties of the Modified Base

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Nanopore Direct RNA Sequencing for Modified Uridine Nucleotides Yields Signals Dependent on the Physical Properties of the Modified Base


Abstract

Sequencing for RNA modifications with the nanopore direct RNA sequencing platform provides ionic current levels, helicase dwell times, and base call data that differentiate the modifications from the canonical form. Herein, model RNAs were synthesized with site-specific uridine (U) base modifications that enable the study of increasing an alkyl group size, halogen identity, or a change in base acidity to impact the nanopore data. The analysis concluded that increases in alkyl size trend with greater current blockage but a similar change in base-call error was not found. The addition of a halogen series to C5 of U revealed that the current levels recorded a trend with the water-octanol partition coefficient of the base, as well as the base call error. Studies with U modifications that are deprotonated (i. e., anionic) under the sequencing conditions gave broad current levels that influenced the base call error. Some modifications led to helicase dwell time changes. These insights provide design parameters for modification-specific chemical reagents that can shift nanopore signatures to minimize false positive reads, a known issue with this sequencing approach.

Pathogenicity Prediction of GABAA Receptor Missense Variants

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Pathogenicity Prediction of GABAA Receptor Missense Variants


Abstract

Variants in the genes encoding gamma-aminobutyric acid type A (GABAA) receptor subunits are associated with epilepsy. To date, over 1000 clinical variants have been identified in these genes. However, the majority of these variants lack functional studies and their clinical significance is uncertain although accumulating evidence indicates that proteostasis deficiency is the major disease-causing mechanism. Here, we apply two state-of-the-art modeling tools, namely AlphaMissense and Rhapsody to predict the pathogenicity of saturating missense variants in genes that encode the major subunits of GABAA receptors in the central nervous system, including GABRA1, GABRB2, GABRB3, and GABRG2. We demonstrate that the predicted pathogenicity correlates well between AlphaMissense and Rhapsody. In addition, AlphaMissense pathogenicity score correlates modestly with plasma membrane expression, peak current amplitude, and GABA potency of the variants that have available experimental data. Furthermore, almost all annotated pathogenic variants in the ClinVar database are successfully identified from the prediction, whereas uncertain variants from ClinVar partially due to the lack of experimental data are differentiated into different pathogenicity groups. The pathogenicity prediction of GABAA receptor missense variants provides a resource to the community as well as guidance for future experimental and clinical investigations.

A RaPID Response to SARS‐CoV‐2

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A RaPID Response to SARS-CoV-2


Abstract

Genetically encoded peptide libraries are at the forefront of de novo drug discovery. The RaPID (Random Nonstandard Peptides Integrated Discovery) platform stands out due to the unique combination of flexible in vitro translation (FIT) and mRNA display. This enables the incorporation of non-canonical amino acids, improving chemical diversity and allowing macrocyclisation of the peptide library. The resulting constrained peptides are valued for their strong binding affinity and stability, especially in the context of protein-protein interactions. In response to SARS-CoV-2, the causative agent of the COVID-19 pandemic, the RaPID system proved valuable in identifying high-affinity ligands of viral proteins. Among many peptide ligands of SARS-CoV-2 spike and main protease (Mpro), several macrocycles stand out for their exceptional binding affinities. Structural data showcases distinct binding modes in complex with the receptor-binding domain (RBD) of the spike glycoprotein or the catalytic active site of Mpro. However, translating these in vitro findings into clinical applications remains challenging, especially due to insufficient cell permeability.

Cystic Fibrosis Modulator Therapies: Bridging Insights from CF to other Membrane Protein Misfolding Diseases

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Cystic Fibrosis Modulator Therapies: Bridging Insights from CF to other Membrane Protein Misfolding Diseases


Abstract

Cystic Fibrosis (CF) is a genetic disorder resulting from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to a faulty CFTR protein. Dysfunctional CFTR causes chloride ion imbalance, resulting in dense mucus accumulation in various organs, particularly the lungs. CF treatments focus on symptom management and addressing CFTR′s functional defects. Notably, development of CFTR modulator therapies has significantly advanced CF treatment. These drugs target CFTR protein structural defects induced by mutations, restoring its function and improving CF symptoms. VX-770, a CFTR potentiator, and CFTR correctors like VX-809, VX-661, and VX-445, have gained FDA approval and widespread clinical use, greatly enhancing the health and survival of many CF patients. However, some CFTR mutations lack effective targeted therapies, leaving approximately 6 % of CF patients without suitable options. CFTR modulator therapies have proven essential for combating the underlying causes of protein misfolding diseases, serving as a blueprint for similar treatments in other membrane protein misfolding diseases. This review explores current and future CFTR modulator therapies, and applications of established paradigms to membrane protein misfolding diseases. Ongoing research and innovation hold the potential for further improvements in CF management and the treatment of protein misfolding diseases.