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At least 1,045 records · Page 58Linked to original sources
PubMed2005

The yeast CLC chloride channel is proteolytically processed by the furin-like protease Kex2p in the first extracellular loop.

CLC chloride channels are a family of channel proteins mediating chloride transport across the plasma membrane and intracellular membranes. The single yeast CLC protein Gef1p is localized to the Golgi and endosomal system. Investigating epitope-tagged variants of Gef1p, we found that the channel is proteolytically processed in the secretory pathway. Proteolytic cleavage occurs in the first extracellular loop of the protein at residues KR136/137 and is carried out by the Kex2p protease. Fragments mimicking the N- and C-terminal products of the cleavage reaction are non-functional when expressed alone. However, functional channels can assemble when the two fragments are co-expressed.

Amino Acid Sequence↗
PubMed2005

Gelatin binding to the 8F19F1 module pair of human fibronectin requires site-specific N-glycosylation.

The gelatin (denatured collagen) binding domain of the extracellular matrix protein fibronectin contains three potential N-glycosylation sites. Complete deglycosylation of this domain is known to reduce the thermal stability of the eighth type 1 (8F1) module. We have conducted a site-specific analysis of the structural and functional consequences of N-linked glycosylation in the 8F19F1 module pair. Three glycoforms have been identified by mass spectrometry and nuclear magnetic resonance spectroscopy. Chemical shift differences between the glycoforms have revealed an intimate interaction between one N-linked sugar and the polypeptide that is critical for gelatin binding, as shown by affinity chromatography.

Amino Acid Sequence↗
PubMed2026

In vivo epigenome editing reduces circulating lipids and attenuates atherosclerosis in mice.

Atherosclerotic cardiovascular disease remains the leading cause of global mortality, with hypercholesterolemia serving as a critical driver of atherogenesis. Although current lipid-lowering therapies substantially improve circulating lipid profiles, strategies that provide more durable, safe, and efficient control of lipid metabolism are still needed. Epigenome editing offers a promising approach for long-lasting repression of disease-modifying genes without altering the underlying DNA sequence. Here, we develop CRISPRoff platforms delivered by adeno-associated virus or lipid nanoparticle to epigenetically silence hepatic Hmgcr or Pcsk9 in vivo. In both C57BL/6J wild-type and ApoE-/- mice, CRISPRoff mediates robust and durable repression of these targets, leading to marked reductions in circulating total cholesterol, low-density lipoprotein cholesterol, and triglycerides. In the ApoE-/- context, epigenetic silencing of Pcsk9 confers pronounced vascular protection, including decreased lipid accumulation in the liver and aortic root, reduced necrotic core formation, diminished macrophage infiltration, and enhanced plaque stability. Together, these results provide proof of principle that CRISPRoff-based epigenome editing enables stable repression of clinically relevant targets and ameliorates key features of atherosclerotic disease. This work lays the foundation for broader therapeutic applications of epigenetic modulation in cardiovascular disorders.

Animals↗
PubMed2004

Gene expression phenotyping of an ACTH-producing small cell lung cancer line.

DNA microarray techniques were used to compare gene expression in an adrenocorticotropin (ACTH)-producing human small cell lung carcinoma line (DMS-79) with six other small cell lung cancer (SCLC) lines that do not produce ACTH. Twelve genes were expressed at more than five-fold higher levels in DMS-79 cells. Two transcription factors were the genes that exhibited the most remarkable over-expression: T-box 3 mRNA was detected at levels 19.37 +/- 3.78 times those observed in the SCLCs. Thyroid transcription factor (TTF-1, T/ebp, Nkx2.1) was expressed at 14.24 +/- 3.41-fold higher in DMS-79 cells. Seven genes were identified whose expression levels were at least five-fold lower in the ACTH-producing cell line. Variation in culture medium formulation did not significantly affect the gene expression profile of DMS-79 cells and expression data observed in microarray experiments were corroborated by northern blot analysis of RNA from the same cell lines. These experiments reveal new candidate genes that could be involved in the dysregulation of POMC gene expression manifested by ACTH-producing nonpituitary tumors.

Adrenocorticotropic Hormone↗
PubMed2026

Comparative safety of lipid-lowering drugs alone or in combination: insights from a systematic review and network meta-analysis.

BACKGROUND AND AIMS: Although the safety profile of lipid-lowering therapies (LLTs) is known, there are no comprehensive comparative assessments. We aimed to compare the risk of muscle-related events, diabetes, liver dysfunction, and cognitive disorders among LLTs through a network meta-analysis. METHODS AND RESULTS: Databases were searched from inception to May 2025. Eligible studies included adult patients, using statins, ezetimibe, PCSK9 monoclonal antibodies (PCSK9mAbs), inclisiran, bempedoic acid, or their combinations as intervention, reporting the information about any of the selected adverse events, a total sample size of ≥200 subjects, and had ≥1 month of intervention. Pooled estimates were assessed by fixed effects model within a frequentist setting. Pooled relative risks (RR) and their 95% confidence interval were estimated. A total of 303,397 subjects from 153 RCTs were included. Bempedoic acid ranked the lowest risk of myalgia (vs PCSK9mAbs, RR 0.80 [0.69, 0.93]). PCSK9mAbs were associated with lower incidence of creatine kinase (CK) elevation, diabetes, and liver dysfunction comparing to statins (statins vs PCSK9mAbs, RR 1.44 [1.14, 1.81], RR 1.13 [1.05, 1.22], and RR 1.38 [1.17, 1.62], respectively). In terms of muscle-related events and cognitive disorders, no significant risk differences were found among treatments and their combinations. CONCLUSIONS: PCSK9mAbs appear to have a more favourable safety profile regarding the risk of CK elevation, diabetes, and liver dysfunction. Bempedoic acid seem to be a better choice for subjects with high risk of myalgia. This information can be valuable when selecting therapy for specific patient subgroups at higher risk of certain adverse events.

Humans↗
PubMed2004

GIFT domains: linking eukaryotic intraflagellar transport and glycosylation to bacterial gliding.

We describe GIFT [for GldG, intraflagellar transport (IFT)] domains in the flavobacterial gliding protein GldG and eukaryotic IFT-52. In eukaryotes, domain homologues are also found in the eukaryotic oligosaccharyltransferase complex and in subtilisin kexin isozyme-1 (SKI-1 or S1P). A distant evolutionary relationship to periplasmic-binding proteins hints that GIFT domains might possess oligosaccharide-binding functions.

Algal Proteins↗
PubMed2004

Ap-let neurons--a peptidergic circuit potentially controlling ecdysial behavior in Drosophila.

Here we describe a novel set of peptidergic neurons conserved throughout all developmental stages in the Drosophila central nervous system (CNS). We show that a small complement of 28 apterous-expressing cells (Ap-let neurons) in the ventral nerve cord (VNC) of Drosophila larvae co-express numerous gene products. The products include the neuroendocrine-specific bHLH regulator called Dimmed (Dimm), four neuropeptide biosynthetic enzymes (PC2, Fur1, PAL2, and PHM), and a specific dopamine receptor subtype (dDA1). For the PC2, Fur1, and PAL2 enzymes, and for the dDA1 receptor, this neuronal pattern represents the vast majority of their total expression in the VNC. In addition, while Dimm and PHM are present in the peritracheal Inka cells in larvae, pupae, and adults, Ap, PC2, Fur1, PAL2, and dDA1 are not. PC2, PAL2, and DA1 receptor expression were all controlled by both dimm and ap. Previous genetic analysis of animals deficient in PC2 revealed an abnormal larval ecdysis phenotype. Together, these data support the hypothesis that the small cohort of Ap-let interneurons regulates larval ecdysis behavior by secretion of an unidentified amidated peptide(s). This hypothesis further predicts that the production of the Ap-let neuropeptide(s) is dependent on each of four specific enzymes, and that a certain aspect(s) of its production and/or release is regulated by dopamine input.

Animals↗
PubMed2001

Amino acid residues involved in the coordination and assembly of the manganese cluster of photosystem II. Proton-coupled electron transport of the redox-active tyrosines and its relationship to water oxidation.

The combination of site-directed mutagenesis, isotopic labeling, new magnetic resonance techniques and optical spectroscopic methods have provided new insights into cofactor coordination and into the mechanism of electron transport and proton-coupled electron transport in photosystem II. Site-directed mutations in the D1 polypeptide of this photosystem have implicated a number of histidine and carboxylate residues in the coordination and assembly of the manganese cluster, responsible for photosynthetic water oxidation. Many of these are located in the carboxy-terminal region of this polypeptide close to the processing site involved in its maturation. This maturation is a required precondition for cluster assembly. Recent proposals for the mechanism of water oxidation have directly implicated redox-active tyrosine Y(Z) in this mechanism and have emphasized the importance of the coupling of proton and electron transfer in the reduction of Y(Z)(radical) by the Mn cluster. The interaction of both homologous redox-active tyrosines Y(Z) and Y(D) with their respective homologous proton acceptors is discussed in an effort to better understand the significance of such coupling.

Algal Proteins↗
PubMed2002

Detection of site-specific proteolysis in secretory pathways.

We report here a genetic assay suitable for detecting site-specific proteolysis in secretory pathways. The yeast enzyme invertase is linked to the truncated lumenal region of the yeast Golgi membrane protein STE13 via a protease substrate domain in a Saccharomyces cerevisiae strain lacking invertase. When the substrate is cleaved by a specific protease, the invertase moiety is released into the periplasmic space where it degrades sucrose to glucose and fructose. Therefore, site-specific proteolysis can be detected by monitoring the growth of yeast cells on selective media containing sucrose as the sole carbon source. We confirmed the validity of this assay with yeast Kex2 and human TMPRSS2 proteases. Our data suggest that this in vivo assay is an efficient method for the determination of substrate specificity and mutational analysis of secreted or membrane proteases.

Biological Assay↗
PubMed2001

A sequential two-step proteolytic process in the carboxyl-terminal truncation of precursor D1 protein in Synechocystis sp. PCC6803.

The D1 protein of photosystem II is synthesized in precursor with a carboxyl-terminal extension. Interestingly, there is quite a range in chain length of the extension, which roughly depends upon the class of organisms. In cyanobacteria, e.g. in Synechocystis sp. PCC6803, the extension consists of 16 amino acid residues, seven residues longer than its counterpart in higher plants. In this study, we examined the D1 processing in Synechocystis sp. PCC6803 by pulse-chase experiments and detected a proteolytic intermediate of this process. This finding suggests that the elongated extension in this organism is excised with a sequential two-step proteolysis, which differs markedly from the manner observed in higher plants.

Algal Proteins↗
PubMed2002

A rapid fluorometric assay for the proteolytic activity of SKI-1/S1P based on the surface glycoprotein of the hemorrhagic fever Lassa virus.

The subtilase subtilisin kexin isozyme-1 (SKI-1)/site 1 protease (S1P), has been implicated in the processing of Lassa virus glycoprotein C (GP-C) precursor into GP1 and GP2 that are responsible for viral fusion with the host cell membrane. Here, we studied in vitro the kinetics of this cleavage by hSKI-1 using an intramolecularly quenched fluorogenic (IQF) peptide, Q-GPC(251-263) [Abz-(251)Asp-Ile-Tyr-Ile-Ser-Arg-Arg-Leu-Leu/Gly-Thr-Phe-Thr(263)-3-NitroTyr-Ala-CONH(2)], containing the identified site. The measured V(max (app))/K(m (app)) was compared to those for other IQF SKI-substrates. Q-GPC(251-263) is cleaved 10-fold more efficiently than the previously known best SKI-substrate, Q-hproSKI(134-142). This study confirmed the role of SKI-1 in GP-C processing and provides a novel, rapid and efficient enzymatic assay of SKI-1.

Chromatography, High Pressure Liquid↗
PubMed1997

Co-elevation of brain natriuretic peptide and proprotein-processing endoprotease furin after myocardial infarction in rats.

We investigated the expression of the yeast Kex2 family endoproteases furin and PACE4, and brain natriuretic peptide (BNP) in the atrium and ventricle after infarction as well as the conversion of the BNP precursor gammaBNP to BNP-45. In a rat heart failure model, plasma BNP rose in two phases--first at day 3, and again at day 14. BNP mRNA, as measured by Northern blot analysis, increased strongly at day 3, then at days 14 and 28 less strongly in the atrium, and in the ventricle it increased weakly at day 3, then strongly at days 14 and 28. Furin mRNA showed the same pattern of expression as that of BNP message, whereas PACE4 message stayed unchanged after the infarction. Both furin and BNP were immunostained in the myocardium adjacent to the infarcted tissue. We suggest that after myocardial infarction, furin is co-expressed with BNP in both the atrium and ventricle, and that furin may be responsible for the conversion of gammaBNP to BNP-45.

Animals↗
PubMed1998

Competitive inhibition analysis of the enzyme-substrate interaction in the carboxy-terminal processing of the precursor D1 protein of photosystem II reaction center using substituted oligopeptides.

A clear parallelism was demonstrated between the efficiency as substrate of the substituted oligopeptides corresponding to the carboxy-terminal (C-terminal) sequence of the precursor D1 protein (pD1) in the in vitro enzymatic assay and their competitive inhibitory capacity toward the proteolytic C-terminal processing of the full-length pD1 integrated in the intact photosystem II complex embedded in the thylakoid membrane of Scenedesmus obliquus LF-1 mutant, as shown e.g. by the influence of L343A, A345G and A345V substitutions and the effect of C-terminal fragments. This suggests that the basic mechanism for substrate recognition by the processing protease elucidated in the enzymatic analysis using synthetic oligopeptides is also effective in vivo, although it can sometimes be difficult to detect the consequence of amino acid substitution in the integrated systems.

Algal Proteins↗
PubMed2002

The disulphide mapping, folding and characterisation of recombinant Ber e 1, an allergenic protein, and SFA8, two sulphur-rich 2S plant albumins.

We have cloned and expressed genes encoding the allergenic brazil nut 2S albumin (Ber e 1) and the sunflower albumin 8 (SFA8) in the methylotrophic yeast Pichia pastoris. We show that both proteins were secreted at high levels and that the purified proteins were properly folded. We also showed that Ber e 1 is glycosylated during secretion and that the glycan does not interfere with the folding or immunoreactivity. The disulphide map of the Ber e 1 protein was experimentally established and is in agreement with the conserved disulphide structure of other members of the 2S albumin family. A model three-dimensional structure of the allergen was generated. During the expression studies and through mutation we have also shown that alteration of the sequences around the Kex2 endoproteolytic processing site in the expressed fusion protein can compromise the secretion by targeting part of the protein for possible degradation. The secreted production of these properly folded sulphur-rich plant albumins presents an opportunity to delineate the attributes that make an allergen and to facilitate the diagnosis and therapy of type I allergy.

2S Albumins, Plant↗
PubMed2003

Mechanisms for lymphocytic choriomeningitis virus glycoprotein cleavage, transport, and incorporation into virions.

The glycoprotein (GP) of lymphocytic choriomeningitis virus (LCMV) serves as virus attachment protein to its receptor on host cells and is a key determinant for cell tropism, pathogenesis, and epidemiology of the virus. The GP of LCMV is posttranslationally cleaved by the subtilase SKI-1/S1P into two subunits, the peripheral GP1, which is implicated in receptor binding, and the transmembrane GP2 that is structurally similar to the fusion active membrane proximal portions of the glycoproteins of other enveloped viruses. The present study shows that cleavage by SKI-1/S1P is not required for cell surface expression of LCMVGP on infected cells but is essential for its incorporation into virions and for the production of infectious virus particles. In absence of SKI-1/S1P cleavage, cell-to-cell propagation of the virus was markedly reduced. Further, proteolytic processing of LCMVGP depends on the presence of a cluster of basic amino acids at the C-terminus of the cytoplasmic domain of GP2, a structural motif that is conserved in Old World arenaviruses. The effect of the truncation of the cytoplasmic tail on cleavage suggests a structural interdependence between the cytoplasmic domain and the ectodomains of LCMVGP.

Amino Acid Sequence↗