The CD3epsilon subunit of the T cell receptor (TCR) complex undergoes a conformational change upon ligand binding that is thought to be important for the activation of T cells. To study this process, we built a molecular dynamics model of the transmission of the conformational change within the ectodomains of CD3. The model showed that the CD3 dimers underwent a stiffening effect that was funneled to the base of the CD3epsilon subunit. Mutation of two relevant amino acid residues blocked transmission of the conformational change and the differentiation and activation of T cells. Furthermore, this inhibition occurred even in the presence of excess endogenous CD3epsilon subunits. These results emphasize the importance of the conformational change in CD3epsilon for the activation of T cells and suggest the existence of unforeseen cooperativity between TCR complexes.
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http://dx.doi.org/10.1126/scisignal.2000402 | DOI Listing |
Clin Epigenetics
December 2024
Hereditary Cancer Group, ONCOBELL Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain.
Background: Lynch syndrome (LS), characterised by an increased risk for cancer, is mainly caused by germline pathogenic variants affecting a mismatch repair gene (MLH1, MSH2, MSH6, PMS2). Occasionally, LS may be caused by constitutional MLH1 epimutation (CME) characterised by soma-wide methylation of one allele of the MLH1 promoter. Most of these are "primary" epimutations, arising de novo without any apparent underlying cis-genetic cause, and are reversible between generations.
View Article and Find Full Text PDFJ Biomed Sci
January 2025
Key Laboratory of Molecular Epigenetics of Ministry of Education, College of Life Sciences, Northeast Normal University, Changchun, 130024, China.
ROS cause multiple forms of DNA damage, and among them, 8-oxoguanine (8-oxoGua), an oxidized product of guanine, is one of the most abundant. If left unrepaired, 8-oxoGua may pair with A instead of C, leading to a mutation of G: C to T: A during DNA replication. 8-Oxoguanine DNA glycosylase 1 (OGG1) is a tailored repair enzyme that recognizes 8-oxoGua in DNA duplex and initiates the base excision repair (BER) pathway to remove the lesion and ensure the fidelity of the genome.
View Article and Find Full Text PDFBMC Biol
December 2024
State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Background: Global climate change significantly impacts ecosystems, particularly through temperature fluctuations that affect insect physiology and behavior. As poikilotherms, insect pests such as the globally devastating diamondback moth (DBM), Plutella xylostella, are especially vulnerable to rising temperatures and extreme heat events, necessitating effective adaptive mechanisms.
Results: Here we demonstrate the roles of zinc finger proteins (ZFPs) in mediating thermal adaptability in DBM.
Commun Chem
December 2024
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
The PepT transporter mediates the transport of peptides across biological membranes. Despite advancements in structural biology, including cryogenic electron microscopy structures resolving PepT in different states, the molecular basis of peptide recognition and transport by PepT is not fully elucidated. In this study, we used molecular dynamics simulations, Markov State Models (MSMs), and Transition Path Theory (TPT) to investigate the transport mechanism of an alanine-alanine peptide (Ala-Ala) through the PepT transporter.
View Article and Find Full Text PDFVet Med Sci
January 2025
Chongqing Three Gouges Vocational College, College of Animal Science & Technology, Wanzhou, China.
Peste des petits ruminants virus (PPRV), a single-stranded negative-sense RNA virus with an envelope, belongs to the Morbillivirus in the Paramyxoviridae family and is prevalent worldwide. PPRV infection causes fever, stomatitis, diarrhoea, pneumonia, abortion and other symptoms in small ruminants, with a high mortality rate that poses a significant threat to the sustainability and productivity of the small ruminant livestock sector. The PPRV virus particles have a diameter of approximately 400-500 nm and are composed of six structural proteins: nucleocapsid protein (N), phosphoprotein (P), envelope matrix protein (M), fusion protein (F), haemagglutinin protein (H) and large protein (L).
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