Search results for "Transmembrane"

Quantitative Proteomics Reveals Changes Induced by TIMP-3 on Cell Membrane Composition and Novel Metalloprotease Substrates

2021

Ectodomain shedding is a key mechanism of several biological processes, including cell-communication. Disintegrin and metalloproteinases (ADAMs), together with the membrane-type matrix metalloproteinases, play a pivotal role in shedding transmembrane proteins. Aberrant shedding is associated to several pathological conditions, including arthritis. Tissue inhibitor of metalloproteases 3 (TIMP-3), an endogenous inhibitor of ADAMs and matrix metalloproteases (MMPs), has been proven to be beneficial in such diseases. Thus, strategies to increase TIMP-3 bioavailability in the tissue have been sought for development of therapeutics. Nevertheless, high levels of TIMP-3 may lead to mechanism-based …

Cytotoxic activity of the histone deacetylase 3-Selective inhibitor Pojamide on MDA-MB-231 triple-negative breast cancer cells

2019

We examined the effects of the ferrocene-based histone deacetylase-3 inhibitor Pojamide (N1-(2-aminophenyl)-N8-ferrocenyloctanediamide) and its two derivatives N1-(2-aminophenyl)-N6-ferrocenyladipamide and N1-(2-aminophenyl)-N8-ferroceniumoctanediamide tetrafluoroborate on triple-negative MDA-MB-231 breast cancer cells. Viability/growth assays indicated that only the first two compounds at 70 &mu

Multicenter validation study for the certification of a CFTR gene scanning method using next generation sequencing technology.

2018

AbstractBackground:Many European laboratories offer molecular genetic analysis of theCFTRgene using a wide range of methods to identify mutations causative of cystic fibrosis (CF) and CFTR-related disorders (CFTR-RDs). Next-generation sequencing (NGS) strategies are widely used in diagnostic practice, and CE marking is now required for most in vitro diagnostic (IVD) tests in Europe. The aim of this multicenter study, which involved three European laboratories specialized in CF molecular analysis, was to evaluate the performance of Multiplicom’s CFTR MASTR Dx kit to obtain CE-IVD certification.Methods:A total of 164 samples, previously analyzed with well-established “reference” methods for t…

Membrane insertion and topology of the translocon-associated protein (TRAP) gamma subunit

2017

Translocon-associated protein (TRAP) complex is intimately associated with the ER translocon for the insertion or translocation of newly synthesised proteins in eukaryotic cells. The TRAP complex is comprised of three single-spanning and one multiple-spanning subunits. We have investigated the membrane insertion and topology of the multiple-spanning TRAP-γ subunit by glycosylation mapping and green fluorescent protein fusions both in vitro and in cell cultures. Results demonstrate that TRAP-γ has four transmembrane (TM) segments, an Nt/Ct cytosolic orientation and that the less hydrophobic TM segment inserts efficiently into the membrane only in the cellular context of full-length protein.

Targeting Nonsense: Optimization of 1,2,4-Oxadiazole TRIDs to Rescue CFTR Expression and Functionality in Cystic Fibrosis Cell Model Systems

2020

Cystic fibrosis (CF) patients develop a severe form of the disease when the cystic fibrosis transmembrane conductance regulator (CFTR) gene is affected by nonsense mutations. Nonsense mutations are responsible for the presence of a premature termination codon (PTC) in the mRNA, creating a lack of functional protein. In this context, translational readthrough-inducing drugs (TRIDs) represent a promising approach to correct the basic defect caused by PTCs. By using computational optimization and biological screening, we identified three new small molecules showing high readthrough activity. The activity of these compounds has been verified by evaluating CFTR expression and functionality after…

Closed-Locked and Apo-Resting State Structures of the Human α7 Nicotinic Receptor: A Computational Study

2018

International audience; Nicotinic acetylcholine receptors, belonging to the Cys-loop super-family of ligand-gated ion channels (LGICs), are membrane proteins present in neurons and at neuromuscular junctions. They are responsible for signal transmission, and their function is regulated by neurotransmitters, agonists and antagonists drugs. A detailed knowledge of their conformational transition in response to ligand binding is critical to understand the basis of ligand-receptor interaction, in view of new pharmacological approaches to control receptor activity. However, the scarcity of experimentally derived structures of human channels makes this perspective extremely challenging. To contri…

Vibrational and Molecular Properties of Mg2+ Binding and Ion Selectivity in the Magnesium Channel MgtE

2018

Magnesium ions (Mg2+) are crucial for various biological processes. A bacterial Mg2+ channel, MgtE, tightly regulates the intracellular Mg2+ concentration. Previous X-ray crystal structures showed that MgtE forms a dimeric structure composed of a total of 10 transmembrane α helices forming a central pore, and intracellular soluble domains constituting a Mg2+ sensor. The ion selectivity for Mg2+ over Ca2+ resides at a central cavity in the transmembrane pore of MgtE, involving a conserved aspartate residue (Asp432) from each monomer. Here, we applied ion-exchange-induced difference FTIR spectroscopy to analyze the interactions between MgtE and divalent cations, Mg2+ and Ca2+. Using site-dire…

Strategies against nonsense: oxadiazoles as translational readthrough-inducing drugs (TRIDs)

2019

This review focuses on the use of oxadiazoles as translational readthrough-inducing drugs (TRIDs) to rescue the functional full-length protein expression in mendelian genetic diseases caused by nonsense mutations. These mutations in specific genes generate premature termination codons (PTCs) responsible for the translation of truncated proteins. After a brief introduction on nonsense mutations and their pathological effects, the features of various classes of TRIDs will be described discussing differences or similarities in their mechanisms of action. Strategies to correct the PTCs will be presented, particularly focusing on a new class of Ataluren-like oxadiazole derivatives in comparison …

The Role of Hydrophobic Mismatch on Transmembrane Helix Dimerization in Living Cells

2019

Stimulus Perception in Bacterial Signal-Transducing Histidine Kinases

2006

SUMMARY Two-component signal-transducing systems are ubiquitously distributed communication interfaces in bacteria. They consist of a histidine kinase that senses a specific environmental stimulus and a cognate response regulator that mediates the cellular response, mostly through differential expression of target genes. Histidine kinases are typically transmembrane proteins harboring at least two domains: an input (or sensor) domain and a cytoplasmic transmitter (or kinase) domain. They can be identified and classified by virtue of their conserved cytoplasmic kinase domains. In contrast, the sensor domains are highly variable, reflecting the plethora of different signals and modes of sens…