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Smriti Kala Nichole Cumby Paul D. Sadowski Batool Zafar Hyder Voula Kanelis Alan R. Davidson Karen L. Maxwell 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(16):6022-6027
The genome packaging reactions of tailed bacteriophages and herpes viruses require the activity of a terminase enzyme, which is comprised of large and small subunits. Phage genomes are replicated as linear concatemers composed of multiple copies of the genome joined end to end. As the terminase enzyme packages the genome into the phage capsid, it cleaves the DNA into single genome-length units. In this work, we show that the phage HK97 HNH protein, gp74, is required for the specific endonuclease activity of HK97 terminase and is essential for phage head morphogenesis. HNH proteins are a very common family of proteins generally associated with nuclease activity that are found in all kingdoms of life. We show that the activity of gp74 in terminase-mediated cleavage of the phage cos site relies on the presence of an HNH motif active-site residue, and that the large subunit of HK97 terminase physically interacts with gp74. Bioinformatic analysis reveals that the role of HNH proteins in terminase function is widespread among long-tailed phages and is uniquely required for the activity of the Terminase_1 family of large terminase proteins.Tailed bacteriophages and herpes viruses package their large double-stranded DNA genomes into a preformed protein shell, known as the “prohead,” using terminase enzymes. In both types of viruses, the genome is synthesized as concatemers composed of multiple copies of the genome joined end to end. This concatemeric DNA is packaged into the prohead and cleaved into genome-length units by terminase in an ATP-dependent reaction. Phage terminases are composed of two proteins: the large subunit harbors an endonuclease domain and an ATPase that powers the DNA packaging reaction, and the small subunit mediates specific DNA-binding required for recognition of packaging sites in the phage genome. A variety of elegant structural and biophysical studies have recently provided insight into the molecular mechanisms of terminase function (1, 2). However, the factors that affect the action of terminase enzymes in vivo have been less well characterized.Terminase enzymes perform several functions. They specifically recognize and bind the viral genome, interact with the prohead, then drive the DNA into the head through the narrow entry channel formed by the portal protein that is positioned at a single vertex of the head. During this process terminases also cleave the viral DNA, either nonspecifically upon head filling or at a specific site known as “cos.” The efficient packaging of a phage genome in vivo may require phage-encoded cofactors in addition to the terminase enzyme. For example, Escherichia coli phage λ gpFI facilitates interaction of the terminase–DNA complex with proheads (3–6). A wide variety of phages appear to encode proteins with a function similar to λ gpFI (7). Additionally, the activity of Bacillus subtilis phage phi29 terminase requires a phage-encoded RNA molecule bound to its portal protein (8), and in vivo packaging of the E. coli phage T4 genome can only be completed with the participation of the phage-encoded endonuclease, gp49 (9). The general prevalence and importance of terminase cofactors is difficult to evaluate because few studies have addressed this issue.We recently reported that phage genomes often encode proteins possessing an HNH motif near their terminase genes (10). The HNH motif is ∼35 aa long, and is characterized by the presence of two highly conserved His residues and one Asn residue. These HNH motifs, as defined by the large (∼7,400-member) HNH Pfam (11) protein sequence family (PF01844), are often found in proteins that possess endonuclease activity, such as site-specific homing endonucleases (12, 13), colicins (14, 15), S pyocins (16), and restriction enzymes (17–19). HNH motif-containing proteins comprised of primarily an HNH motif as found in E. coli colicins, usually possess nonspecific endonuclease activity. Conversely, HNH motif-containing proteins may contain DNA-recognition domains in addition to the HNH motif and thus possess high sequence specificity, as found in the homing endonucleases.The frequent juxtaposition of HNH and phage terminase genes (10, 20) suggests a unique role for HNH proteins in the endonuclease and/or packaging activities of the terminases. To address this issue, we investigated the function of E. coli phage HK97 gp74, a 119-residue protein containing an HNH motif. The gene encoding gp74 is located at the extreme 3′ end of the mature linear HK97 genome, adjacent to the cos site. In both the lysogen and replicative form of the HK97 genome gene 74 is immediately adjacent to genes 1 and 2, which encode the small and large subunits of terminase (TerS and TerL), respectively. Whereas gp74 was previously found to possess endonuclease activity (10), its role in the HK97 replication cycle remained uncharacterized. In this study we used functional and bioinformatic analyses to investigate its function. 相似文献
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Smriti Kanangat Christopher W. Seder Melissa R. Pergande Gabriela C. Lobato Cristina L. Fhied Maryam F. Raouf Michael J. Liptay Jeffrey A. Borgia 《Human immunology》2018,79(7):558-563
Background
This study explores the potential diagnostic utility of soluble Human Leukocyte Antigen (sHLA) molecules differentially released by lung adenocarcinoma and benign lung lesions.Methods
Conditioned media from the NSCLC cell lines H358 and H1703 were immunoblotted for soluble isoforms of major histocompatibility complex (MHC) class I (ABC) and II (DRB1, DMB, and DQ) antigens. Sera from 25 patients with benign and 25 patients with malignant lesions were similarly evaluated to appraise the potential diagnostic value.Results
Higher concentrations of soluble HLA class I molecules were observed in conditioned medium for the highly-invasive H1703 cell line, relative to the more indolent H358 cells. Evaluation of these markers against a cohort of 50 cases demonstrated that patients with malignant lesions possess higher levels of HLA class I and II molecules relative to those with benign lesions (p?<?0.05), with exception to the primary isoform, DQA1, which was suppressed in malignancies. An analysis of biomarker performance via ROC analysis revealed promising performance (AUC?>?0.75) for DMB and the 26?kDa isoform of DQ in distinguishing lesion pathology.Conclusions
Soluble HLA molecules may have diagnostic value for early-stage NSCLC. Validation studies are currently underway using sera from a lung cancer screening cohort. 相似文献4.
5.
Iyengar S Webster AA Hemrick-Luecke SK Xu JY Simmons RM 《The Journal of pharmacology and experimental therapeutics》2004,311(2):576-584
5-Hydroxytryptamine (serotonin) (5-HT) and norepinephrine (NE) are implicated in modulating descending inhibitory pain pathways in the central nervous system. Duloxetine is a selective and potent dual 5-HT and NE reuptake inhibitor (SNRI). The ability of duloxetine to antagonize 5-HT depletion in para-chloramphetamine-treated rats was comparable with that of paroxetine, a selective serotonin reuptake inhibitor (SSRI), whereas its ability to antagonize NE depletion in alpha-methyl-m-tyrosine-treated rats was similar to norepinephrine reuptake inhibitors (NRIs), thionisoxetine or desipramine. In this paradigm, duloxetine was also more potent than other SNRIs, including venlafaxine or milnacipran and amitriptyline. Low doses of the SSRI paroxetine or the NRI thionisoxetine alone did not have an effect on late phase paw-licking pain behavior in the formalin model of persistent pain; however, when combined, significantly attenuated this pain behavior. Duloxetine (3-15 mg/kg intraperitoneal) significantly attenuated late phase paw-licking behavior in a dose-dependent manner in the formalin model and was more potent than venlafaxine, milnacipran, and amitriptyline. These effects of duloxetine were evident at doses that did not cause neurologic deficits in the rotorod test. Duloxetine (5-30 mg/kg oral) was also more potent and efficacious than venlafaxine and milnacipran in reversing mechanical allodynia behavior in the L5/L6 spinal nerve ligation model of neuropathic pain. Duloxetine (3-30 mg/kg oral) was minimally efficacious in the tail-flick model of acute nociceptive pain. These data suggest that inhibition of both 5-HT and NE uptake may account for attenuation of persistent pain mechanisms. Thus, duloxetine may have utility in treatment of human persistent and neuropathic pain states. 相似文献
6.
Daniel J. Blackman Smriti Saraf Philip A. MacCarthy Aung Myat Simon G. Anderson Christopher J. Malkin Michael S. Cunnington Kathryn Somers Paul Brennan Ganesh Manoharan Jessica Parker Omar Aldalati Stephen J. Brecker Cameron Dowling Stephen P. Hoole Stephen Dorman Michael Mullen Simon Kennon David Hildick-Smith 《Journal of the American College of Cardiology》2019,73(5):537-545
Background
Very little is known about long-term valve durability after transcatheter aortic valve replacement (TAVR).Objectives
This study sought to evaluate the incidence of structural valve degeneration (SVD) 5 to 10 years post-procedure.Methods
Demographic, procedural, and in-hospital outcome data on patients who underwent TAVR from 2007 to 2011 were obtained from the U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) registry. Patients in whom echocardiographic data were available both at baseline and ≥5 years post-TAVR were included. Hemodynamic SVD was determined according to European task force committee guidelines.Results
A total of 241 patients (79.3 ± 7.5 years of age; 46% female) with paired post-procedure and late echocardiographic follow-up (median 5.8 years, range 5 to 10 years) were included. A total of 149 patients (64%) were treated with a self-expandable valve and 80 (34.7%) with a balloon-expandable valve. Peak aortic valve gradient at follow-up was lower than post-procedure (17.1 vs. 19.1 mm Hg; p = 0.002). More patients had none/trivial aortic regurgitation (AR) (47.5% vs. 33%), and fewer had mild AR (42.5% vs. 57%) at follow-up (p = 0.02). There was 1 case (0.4%) of severe SVD 5.3 years after implantation (new severe AR). There were 21 cases (8.7%) of moderate SVD (mean 6.1 years post-implantation; range 4.9 to 8.6 years). Twelve of these (57%) were due to new AR and 9 (43%) to restenosis.Conclusions
Long-term transcatheter aortic valve function is excellent. In the authors’ study, 91% of patients remained free of SVD between 5 and 10 years post-implantation. The incidence of severe SVD was <1%. Moderate SVD occurred in 1 in 12 patients. 相似文献7.
mTOR Signaling Cascade in Psoriatic Disease: Double Kinase mTOR Inhibitor a Novel Therapeutic Target
In this short communication we are providing insight about the regulatory role of the phosphatidylinositol 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) kinase system in psoriatic disease. This is an upcoming active research field in respect to elucidating the inflammatory and proliferative cascades of psoriatic disease. To provide a new dimension to the understandings of the molecular principles of the pathogenesis of autoimmune diseases, we hypothesized that (i) dysregulation of cytokines and growth factors in autoimmune diseases activate the mTOR signaling system and (ii) the activated mTOR kinase system is a key regulator of the inflammatory/proliferative cascades of the disease process. In support of this hypothesis we have earlier reported that growth factors (nerve growth factor (NGF) and platelet-derived growth factor (PDGF)) and relevant cytokines (interleukin (IL)-17, IL-22) known to be critical for psoriasis, psoriatic arthritis, and rheumatoid arthritis activate the mTOR signaling system. Here, we are providing our latest observations that the mTOR signaling proteins are upregulated in psoriatic skin and further we observed that proliferation of keratinocytes (KC) and synovial cells (synovial fibroblasts (FLS)) of psoriatic arthritis are dependent on the PI3K-AKT-mTOR kinase system. To our knowledge, we are the first to explore whether a double kinase inhibitor of mTOR signal proteins has a therapeutic potential for psoriatic disease. Here we will be sharing our views, our research work in this field and as well we will provide evidences how a double kinase inhibitor of mTOR signal proteins can be an effective therapeutic agent for psoriatic disease. 相似文献
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Kumar Namrata Das Vinita Agarwal Anjoo Pandey Amita Agrawal Smriti Singh Amrita 《Journal of obstetrics and gynaecology of India》2020,70(1):23-29
The Journal of Obstetrics and Gynecology of India - Hypertensive disorders of pregnancies complicate around 5–10% of pregnancies worldwide, and together they are a member of the deadly triad... 相似文献