59 research outputs found

    Effect of temperature on the growth of the commercially fished common whelk (Buccinum undatum, L.): a regional analysis within the Irish Sea

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    In response to increased demand in Asian markets, the commercial fishery for the common whelk (Buccinum undatum, L) has expanded in north-eastern Europe. In the Irish Sea region (ICES Area 20 VHa), increased effort and landings have raised concerns about long-term stability of the fishery amongst stakeholders. Fisheries in Welsh waters and the Isle of Man territorial sea are now subject to an increased minimum landing size according to the best available scientific data. This study addresses key knowledge gaps by investigating the size-at-age relationship of the species across the latitudinal extent of the fisheries management region. Our findings show that growth parameters, modelled using growth rings observed in the statolith, vary between populations and show a broadly latitudinal pattern. Thermal-time (expressed as sea bottom temperature degree-days) showed a significant negative linear relationship with the asymptotic size reach by whelk populations (L-infinity), where whelk grew to a larger maximum size in cooler waters. Other parameters, including maximum growth rates and the age at which growth rate begins to decrease, showed clear trends with sea-bottom temperature but linear modelling failed to detect significant relationships, where warmer waters increase the rate of growth in the early life stages of whelk but cooler waters allow growth to continue until later in life. Whilst there are substantial requirements to further validate and refine the relationship between growth and sea-bottom temperature, extrapolation of these data to other regions in Northeast Europe may provide a valuable tool in approximating important life-history characteristics in stock assessments, such as L-infinity, age-at-L-50 and age-at-recruitment

    Neuropathic MORC2 mutations perturb GHKL ATPase dimerization dynamics and epigenetic silencing by multiple structural mechanisms

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    Missense mutations in MORC2 cause neuropathies including spinal muscular atrophy and Charcot-Marie-Tooth disease. We recently identified MORC2 as an effector of epigenetic silencing by the human silencing hub (HUSH). Here we report the biochemical and cellular activities of MORC2 variants, alongside crystal structures of wild-type and neuropathic forms of a human MORC2 fragment comprising the GHKL-type ATPase module and CW-type zinc finger. This fragment dimerizes upon binding ATP and contains a hinged, functionally critical coiled coil insertion absent in other GHKL ATPases. We find that dimerization and DNA binding of the MORC2 ATPase module transduce HUSH-dependent silencing. Disease mutations change the dynamics of dimerization by distinct structural mechanisms: destabilizing the ATPase-CW module, trapping the ATP lid or perturbing the dimer interface. These defects lead to modulation of HUSH function, thus providing a molecular basis for understanding MORC2-associated neuropathies

    Norden, reframed

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    This paper calls for Norden to be understood as a metaframe. Related formulations like “Nordic art” or “Nordic welfare” function as mesoframes. These trigger multiple framing devices. A cache of related framing devices constitutes a framing archive. Framing devices work best when operating unobtrusively such that inclusions, exclusions and inconsistencies are condoned or naturalised. Their artifice, however, becomes apparent whenever a frame is questioned. Questioning or criticising a frame gives rise to a framing dispute. The theoretical justification for these typologies is provided at the outset. This schema is then applied to a select range of empirical examples drawn largely from the disciplinary frames (Ernst 1996) of art history and museum studies. Despite this specificity it is envisaged that the general principles set out below can and will be used to address a variety of devices, disputes and archives in Norden and beyond

    Specific Recognition of Linear Ubiquitin Chains by NEMO Is Important for NF-κB Activation

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    Activation of nuclear factor-κB (NF-κB), a key mediator of inducible transcription in immunity, requires binding of NF-κB essential modulator (NEMO) to ubiquitinated substrates. Here, we report that the UBAN (ubiquitin binding in ABIN and NEMO) motif of NEMO selectively binds linear (head-to-tail) ubiquitin chains. Crystal structures of the UBAN motif revealed a parallel coiled-coil dimer that formed a heterotetrameric complex with two linear diubiquitin molecules. The UBAN dimer contacted all four ubiquitin moieties, and the integrity of each binding site was required for efficient NF-κB activation. Binding occurred via a surface on the proximal ubiquitin moiety and the canonical Ile44 surface on the distal one, thereby providing specificity for linear chain recognition. Residues of NEMO involved in binding linear ubiquitin chains are required for NF-κB activation by TNF-α and other agonists, providing an explanation for the detrimental effect of NEMO mutations in patients suffering from X-linked ectodermal dysplasia and immunodeficiency

    Cleavage by signal peptide peptidase is required for the degradation of selected tail-anchored proteins.

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    The regulated turnover of endoplasmic reticulum (ER)-resident membrane proteins requires their extraction from the membrane lipid bilayer and subsequent proteasome-mediated degradation. Cleavage within the transmembrane domain provides an attractive mechanism to facilitate protein dislocation but has never been shown for endogenous substrates. To determine whether intramembrane proteolysis, specifically cleavage by the intramembrane-cleaving aspartyl protease signal peptide peptidase (SPP), is involved in this pathway, we generated an SPP-specific somatic cell knockout. In a stable isotope labeling by amino acids in cell culture-based proteomics screen, we identified HO-1 (heme oxygenase-1), the rate-limiting enzyme in the degradation of heme to biliverdin, as a novel SPP substrate. Intramembrane cleavage by catalytically active SPP provided the primary proteolytic step required for the extraction and subsequent proteasome-dependent degradation of HO-1, an ER-resident tail-anchored protein. SPP-mediated proteolysis was not limited to HO-1 but was required for the dislocation and degradation of additional tail-anchored ER-resident proteins. Our study identifies tail-anchored proteins as novel SPP substrates and a specific requirement for SPP-mediated intramembrane cleavage in protein turnover

    Proteomic plasma membrane profiling reveals an essential role for gp96 in the cell surface expression of LDLR family members, including the LDL receptor and LRP6.

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    The endoplasmic reticulum chaperone gp96 is required for the cell surface expression of a narrow range of proteins, including toll-like receptors (TLRs) and integrins. To identify a more comprehensive repertoire of proteins whose cell surface expression is dependent on gp96, we developed plasma membrane profiling (PMP), a technique that combines SILAC labeling with selective cell surface aminooxy-biotinylation. This approach allowed us to compare the relative abundance of plasma membrane (PM) proteins on gp96-deficient versus gp96-reconstituted murine pre-B cells. Analysis of unfractionated tryptic peptides initially identified 113 PM proteins, which extended to 706 PM proteins using peptide prefractionation. We confirmed a requirement for gp96 in the cell surface expression of certain TLRs and integrins and found a marked decrease in cell surface expression of four members of the extended LDL receptor family (LDLR, LRP6, Sorl1 and LRP8) in the absence of gp96. Other novel gp96 client proteins included CD180/Ly86, important in the B-cell response to lipopolysaccharide. We highlight common structural motifs in these client proteins that may be recognized by gp96, including the beta-propeller and leucine-rich repeat. This study therefore identifies the extended LDL receptor family as an important new family of proteins whose cell surface expression is regulated by gp96

    Human embryonic stem cell-derived cardiomyocyte platform screens inhibitors of SARS-CoV-2 infection.

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    Patients with cardiovascular comorbidities are more susceptible to severe infection with SARS-CoV-2, known to directly cause pathological damage to cardiovascular tissue. We outline a screening platform using human embryonic stem cell-derived cardiomyocytes, confirmed to express the protein machinery critical for SARS-CoV-2 infection, and a SARS-CoV-2 spike-pseudotyped virus system. The method has allowed us to identify benztropine and DX600 as novel inhibitors of SARS-CoV-2 infection in a clinically relevant stem cell-derived cardiomyocyte line. Discovery of new medicines will be critical for protecting the heart in patients with SARS-CoV-2, and for individuals where vaccination is contraindicated
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