Sp140 is a multi-SUMO-1 target and its PHD finger promotes SUMOylation of the adjacent Bromodomain.

Abstract Background Human Sp140 protein is a leukocyte-specific member of the speckled protein (Sp) family (Sp100, Sp110, Sp140, Sp140L), a class of multi-domain nuclear proteins involved in intrinsic immunity and transcriptional regulation. Sp140 regulates macrophage transcriptional program and is implicated in several haematologic malignancies. Little is known about Sp140 structural domains and its post-translational modifications. Methods We used mass spectrometry and biochemical experiments to investigate endogenous Sp140 SUMOylation in Burkitt's Lymphoma cells and Sp140 SUMOylation sites in HEK293T cells, FLAG-Sp140 transfected and His6-SUMO-1T95K infected. NMR spectroscopy and in vitro SUMOylation reactions were applied to investigate the role of Sp140 PHD finger in the SUMOylation of the adjacent BRD. Results Endogenous Sp140 is a SUMO-1 target, whereby FLAG-Sp140 harbors at least 13 SUMOylation sites distributed along the protein sequence, including the BRD. NMR experiments prove direct binding of the SUMO E2 ligase Ubc9 and SUMO-1 to PHD-BRDSp140. In vitro SUMOylation reactions show that the PHDSp140 behaves as SUMO E3 ligase, assisting intramolecular SUMOylation of the adjacent BRD. Conclusions Sp140 is multi-SUMOylated and its PHD finger works as versatile protein-protein interaction platform promoting intramolecular SUMOylation of the adjacent BRD. Thus, combinatorial association of Sp140 chromatin binding domains generates a multifaceted interaction scaffold, whose function goes beyond the canonical histone recognition. General significance The addition of Sp140 to the increasing lists of multi-SUMOylated proteins opens new perspectives for molecular studies on Sp140 transcriptional activity, where SUMOylation could represent a regulatory route and a docking surface for the recruitment and assembly of leukocyte-specific transcription regulators

A persulfidation-based mechanism controls aquaporin-8 conductance

Upon engagement of tyrosine kinase receptors, nicotinamide adenine dinucleotide phosphate (NADPH)-oxidases release H2O2 in the extracellular space. We reported previously that aquaporin-8 (AQP8) transports H2O2 across the plasma membrane and is reversibly gated during cell stress, modulating signal strength and duration. We show that AQP8 gating is mediated by persulfidation of cysteine 53 (C53). Treatment with H2S is sufficient to block H2O2 entry in unstressed cells. Silencing cystathionine beta-synthase (CBS) prevents closure, suggesting that this enzyme is the main source of H2S. Molecular modeling indicates that C53 persulfidation displaces a nearby histidine located in the narrowest part of the channel. We propose that H2O2 molecules transported through AQP8 sulfenylate C53, making it susceptible to H2S produced by CBS. This mechanism tunes H2O2 transport and may control signaling and limit oxidative stress.This work was supported in part through grants from the Associazione Italiana Ricerca sul Cancro (IG 2016-18824 to R.S. and IG 2016-15434 to A.R.), the Fondazione Cariplo (2015-0591 to R.S.), the Ministero della Salute (PE-2011-02352286 to R.S. and RF-2013-02354880 to G.M.), the Telethon (GGP15059 to R.S.), and the "Cinque per mille"; (to A.R.). G.P.B. was supported by an Emmy Noether grant 1668/1-1 from the Deutsche Forschungsgemeinschaft

A stapled chromogranin A-derived peptide is a potent dual ligand for integrins αvβ6 and αvβ8

Combining 2D STD-NMR, computation, biochemical assays and click-chemistry, we have identified a chromogranin-A derived compound (5) that has high affinity and bi-selectivity for αvβ6 and αvβ8 integrins and is stable in microsomal preparations

ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients

A novel extremely localized molecular orbitals based technique for the one-electron density matrix computation

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Dissecting intrinsic and ligand-induced structural communication in the \u3b23 headpiece of integrins

Background: Graph theory is widely used to dissect structural communication in biomolecular systems. Here, graph theory-based approaches were applied to the headpiece of integrins, adhesion cell-surface receptors that transmit signals across the plasma membranes. Methods: Protein Structure Network (PSN) analysis incorporating dynamic information either from molecular dynamics simulations or from Elastic Network Models was applied to the \u3b23 domains from integrins \u3b1V\u3b23 and \u3b1IIb\u3b23 in their apo and ligand-bound states. Results: Closed and open states of the \u3b2 headpiece are characterized by distinct allosteric communication pathways involving highly conserved amino acids at the two different \u3b1/\u3b2 interfaces in the \u3b2I domain, the closed state being prompted to the closed-to-open transition. In the closed state, pure antagonism is associated with the establishment of communication pathways that start from the ligand, pass through the \u3b21/\u3b13,\u3b14 interface, and end up in the hybrid domain by involving the Y110-Q82 link, which is weakened in the agonist-bound states. Conclusions: Allosteric communication in integrins relies on highly conserved and functionally relevant amino acid residues. The \u3b1\u3b2\u3b1-sandwich architecture of integrin \u3b2I domain dictates the structural communication between ligand binding site and hybrid domain. Differently from agonists, pure antagonists are directly involved in allosteric communication pathways and exert long-distance strengthening of the \u3b2I/hybrid interface. Release of the structure network in the ligand binding site is associated with the close-to-open transition accompanying the activation process. General significance: The study strengthens the power of graph-based analyses to decipher allosteric communication intrinsic to protein folds and modified by functionally different ligands

Extremely localized molecular orbitals: theory and applications

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Mutations Conferring Increased Sensitivity to Tripartite Motif 22 Restriction Accumulated Progressively in the Nucleoprotein of Seasonal Influenza A (H1N1) Viruses between 1918 and 2009

International audienceInfluenza A viruses (IAVs) can cause zoonotic infections with pandemic potential when most of the human population is immunologically naive. After a pandemic, IAVs evolve to become seasonal in the human host by acquiring adaptive mutations. We have previously reported that the interferon (IFN)-inducible tripartite motif 22 (TRIM22) protein restricts the replication of seasonal IAVs by direct interaction with the viral nucleoprotein (NP), leading to its polyubiquitination and protea-somal degradation. Here we show that, in contrast to seasonal H1N1 IAVs, the 2009 pandemic H1N1 strain as well as H1N1 strains from the 1930s are resistant to TRIM22 restriction. We demonstrate that arginine-to-lysine substitutions conferring an increased sensitivity to TRIM22-dependent ubiquitination accumulated progressively in the NP of seasonal influenza A (H1N1) viruses between 1918 and 2009. Our findings suggest that during long-term circulation and evolution of IAVs in humans, adaptive mutations are favored at the expense of an increased sensitivity to some components of the innate immune response. IMPORTANCE We have uncovered that long-term circulation of seasonal influenza A viruses (IAV) in the human population resulted in the progressive acquisition of increased sensitivity to a component of the innate immune response: the type I interferon-inducible TRIM22 protein, which acts as a restriction factor by inducing the polyubiquiti-nation of the IAV nucleoprotein (NP). We show that four arginine residues present in the NP of the 1918 H1N1 pandemic strain and early postpandemic strains were progressively substituted for by lysines between 1918 and 2009, rendering NP more susceptible to TRIM22-mediated ubiquitination. Our observations suggest that during long-term evolution of IAVs in humans, variants endowed with increased susceptibility to TRIM22 restriction emerge, highlighting the complexity of selection pressures acting on the NP

Ghitti. Memoria del ferro. Iron Memory

Il libro, dedicato al lavoro dell’artista Franca Ghitti, prende in considerazione quel lungo percorso dell’artista che opera in istallazioni che utilizzano il ferro residuale attingendo a stampi o scarti di fucina (sfridi e contorni d’attrezzi agricoli e domestici) che recano l’impronta di un territorio stratificato di vite vissute insieme. La scultura della Ghitti risale alle radici antropologiche dell’arte, ma per approdare a inedite produzioni di senso. In un nuovo comporre contemporaneo, urbano si riconoscono tuttavia le strutture storiche che ricompaginano tra noi e le cose del mondo in un paziente lavoro di memoria che ridesta il senso della vita comunitaria. Nel testo Cancelli d’Europa dedicato a una serie di istallazioni così intitolate si evidenzia come la Ghitti lavori a una nuova serie secondo una modalità processuale che le è propria. Recuperando all’interno del più grande capitolo Memoria del ferro le premesse di tale nuova serie si identificano in alcune opere, come La porta del silenzio, l’elemento di cesura e allo stesso tempo di passaggio. Dopo la caduta del muro di Berlino e la formulazione politica dell’Europa unita, una cittadinanza che abbatte frontiere e dogane in una libera circolazione di merci e persone, riemerge prepotente la ricerca delle origini. Frutto di un disegno interno gli sfridi utilizzati nelle sue istallazioni ne portano la traccia, eredità di una cultura contadina, del lavoro che ha civilizzato l’Europa.The book, dedicated to the work of Franca Ghitti takes into consideration the long path of the artist who works in installations using the residual iron by drawing on molds or forge scraps (scraps and contours of farm and domestic tools) bearing the mark of a stratified territory of lives lived together. The sculpture of Ghitti dates back to the anthropological roots of art, but to arrive to unreleased meaning productions. In a new contemporary, urban composing however we can recognize the historic structures put together between us and the things of the world in a patient work of memory that awakens the sense of community life. In the text Gates of Europe dedicated to a series of installations so entitled it is noted how Ghitti works on a new series according to a modality that has her own characteristic . By retrieving in the largest chapter Memory of the iron the premises of this new series some works are identified, such as The door of silence, the element of caesura and, at the same time, of passage. After the fall of the Berlin Wall and the politic formulation of a united Europe, a citizenship that breaks down frontiers and customs authorities in a free movement of goods and people, bully emerges the search for origins. Product of an interior design, the scraps used in her installations bring the track, the legacy of a rural culture, of the work that has civilized Europe