Search results for "proteïnes"
showing 10 items of 89 documents
Transmembrane but not soluble helices fold inside the ribosome tunnel
2018
Integral membrane proteins are assembled into the ER membrane via a continuous ribosome-translocon channel. The hydrophobicity and thickness of the core of the membrane bilayer leads to the expectation that transmembrane (TM) segments minimize the cost of harbouring polar polypeptide backbones by adopting a regular pattern of hydrogen bonds to form α-helices before integration. Co-translational folding of nascent chains into an α-helical conformation in the ribosomal tunnel has been demonstrated previously, but the features governing this folding are not well understood. In particular, little is known about what features influence the propensity to acquire α-helical structure in the ribosom…
Multi-laboratory experiment PME11 for the standardization of phosphoproteome analysis
2022
6 p.-2 fig.-2 tab.
Protein Identification and Haplotype Description of Homozygote Mutation Causing Congenital Plasminogen Deficiency
2021
Severe type I Plasminogen (PLG) deficiency was clinically diagnosed after hyaline-positive periodic acid Schiff material was detected in the histologic study of superior tarsal conjunctiva and vulvar pseudomembrane of the patient. Direct immunofluorescence also confirmed multiple deposits of fibrinogen in the dermis. Plasma plasminogen activity was calculated in a <5% value (reference values, 75% to 150%) and sequencing of the PLG gene evidenced the homozygous mutation in c.2377T/A (p.Tyr793Asn), confirming the molecular diagnosis of congenital deficiency of plasminogen type 1. Genotype-Phenotype correlation among family members evidenced the recessive hereditary pattern of clinical manifes…
Ala-insertion scanning mutagenesis of the glycophorin A transmembrane helix
1996
Alanine insertions into the glycophorinA transmembrane helix are found to disrupthelix-helix dimerization in a way thatis fully consistentwith earlier saturation mutagenesis datas,uggesting that Ala-insertion scanning can be used to rapidly map the approximate locatiofn structurally and/or functionally importantsegments in trans-membrane helices
Pdl1 Is a Putative Lipase that Enhances Photorhabdus Toxin Complex Secretion
2012
The Toxin Complex (TC) is a large multi-subunit toxin first characterized in the insect pathogens Photorhabdus and Xenorhabdus, but now seen in a range of pathogens, including those of humans. These complexes comprise three protein subunits, A, B and C which in the Xenorhabdus toxin are found in a 4∶1∶1 stoichiometry. Some TCs have been demonstrated to exhibit oral toxicity to insects and have the potential to be developed as a pest control technology. The lack of recognisable signal sequences in the three large component proteins hinders an understanding of their mode of secretion. Nevertheless, we have shown the Photorhabdus luminescens (Pl) Tcd complex has been shown to associate with th…
The ER-Membrane Transport System Is Critical for Intercellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus.
2015
Plant viruses move through plasmodesmata to infect new cells. The plant endoplasmic reticulum (ER) is interconnected among cells via the ER desmotubule in the plasmodesma across the cell wall, forming a continuous ER network throughout the entire plant. This ER continuity is unique to plants and has been postulated to serve as a platform for the intercellular trafficking of macromolecules. In the present study, the contribution of the plant ER membrane transport system to the intercellular trafficking of the NSm movement protein and Tomato spotted wilt tospovirus (TSWV) is investigated. We showed that TSWV NSm is physically associated with the ER membrane in Nicotiana benthamiana plants. An…
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
2014
Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With -10(2)-10(3) repetitions of the photoreaction, the minimum num…
Elucidating the aryl hydrocarbon receptor antagonism from a chemical-structural perspective.
2020
The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two tox…
Epigenetic activation of a cryptic TBC1D16 transcript enhances melanoma progression by targeting EGFR
2015
Metastasis is respoMetastasis is responsible for most cancer-related deaths, and, among common tumor types, melanoma is one with great potential to metastasize. Here we study the contribution of epigenetic changes to the dissemination process by analyzing the changes that occur at the DNA methylation level between primary cancer cells and metastases. We found a hypomethylation event that reactivates a cryptic transcript of the Rab GTPase activating protein TBC1D16 (TBC1D16-47 kDa; referred to hereafter as TBC1D16-47KD) to be a characteristic feature of the metastatic cascade. This short isoform of TBC1D16 exacerbates melanoma growth and metastasis both in vitro and in vivo. By combining imm…
Binding of PTEN to specific PDZ domains contributes to PTEN protein stability and phosphorylation by microtubule-associated serine/threonine kinases
2005
The tumor suppressor phosphatase PTEN is a key regulator of cell growth and apoptosis that interacts with PDZ domains from regulatory proteins, including MAGI-1/2/3, hDlg, and MAST205. Here we identified novel PTEN-binding PDZ domains within the MAST205-related proteins, syntrophin-associated serine/threonine kinase and MAST3, characterized the regions of PTEN involved in its interaction with distinctive PDZ domains, and analyzed the functional consequences on PTEN of PDZ domain binding. Using a panel of PTEN mutations, as well as PTEN chimeras containing distinct domains of the related protein TPTE, we found that the PTP and C2 domains of PTEN do not affect PDZ domain binding and that the …