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Found 37684 matches. Displaying 4351-4360
Hu WB, Yu XJ, Liu ZZ, Sun Y, Chen XB, Yang X, Li XF, Lam WK, Duan YY, Cao X, Steller H, Liu K, Huang PB
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The complex of TRIP-Br1 and XIAP ubiquitinates and degrades multiple adenylyl cyclase isoforms

ELIFE 2017 JUN 28; 6(?):? Article e28021
Adenylyl cyclases (ACs) generate cAMP, a second messenger of utmost importance that regulates a vast array of biological processes in all kingdoms of life. However, almost nothing is known about how AC activity is regulated through protein degradation mediated by ubiquitination or other mechanisms. Here, we show that transcriptional regulator interacting with the PHD-bromodomain 1 (TRIP-Br1, Sertad1), a newly identified protein with poorly characterized functions, acts as an adaptor that bridges the interaction of multiple AC isoforms with X-linked inhibitor of apoptosis protein (XIAP), a RING-domain E3 ubiquitin ligase. XIAP ubiquitinates a highly conserved Lys residue in AC isoforms and thereby accelerates the endocytosis and degradation of multiple AC isoforms in human cell lines and mice. XIAP/TRIP-Br1-mediated degradation of ACs forms part of a negative-feedback loop that controls the homeostasis of cAMP signaling in mice. Our findings reveal a previously unrecognized mechanism for degrading multiple AC isoforms and modulating the homeostasis of cAMP signaling.
Rosti RO, Sotak BN, Bielas SL, Bhat G, Silhavy JL, Aslanger AD, Altunoglu U, Bilge I, Tasdemir M, Yzaguirrem AD, Musaev D, Infante S, Thuong W, Marin-Valencia I, Nelson SF, Kayserili H, Gleeson JG
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Homozygous mutation in NUP107 leads to microcephaly with steroid-resistant nephrotic condition similar to Galloway-Mowat syndrome

JOURNAL OF MEDICAL GENETICS 2017 JUN; 54(6):399-403
Background Microcephaly with nephrotic syndrome is a rare co-occurrence, constituting the Galloway-Mowat syndrome (GAMOS), caused by mutations in WDR73 (OMIM: 616144). However, not all patients harbour demonstrable WDR73 deleterious variants, suggesting that there are other yet unidentified factors contributing to GAMOS aetiology. Methods Autozygosity mapping and candidate analysis was used to identify deleterious variants in consanguineous families. Analysis of patient fibroblasts was used to study splicing and alterations in cellular function. Results In two consanguineous families with five affected individuals from Turkey with a GAMOS-like presentation, we identified a shared homozygous variant leading to partial exon 4 skipping in nucleoporin, 107-KD (NUP107). The founder mutation was associated with concomitant reduction in NUP107 protein and in the obligate binding partner NUP133 protein, as well as density of nuclear pores in patient cells. Conclusion Recently, NUP107 was suggested as a candidate in a family with nephrotic syndrome and developmental delay. Other NUP107-reported cases had isolated renal phenotypes. With the addition of these individuals, we implicate an allele-specific critical role for NUP107 in the regulation of brain growth and a GAMOS-like presentation.
Srimathveeravalli G, Cornelis F, Wimmer T, Monette S, Kimm SY, Maybody M, Solomon SB, Coleman JA, Durack JC
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Normal Porcine Ureter Retains Lumen Wall Integrity but Not Patency Following Catheter-Directed Irreversible Electroporation: Imaging and Histologic Assessment over 28 Days

JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2017 JUN; 28(6):913-919
Purpose: To evaluate the effect of catheter-directed irreversible electroporation (iRE) on the integrity, patency, and function of the normal porcine ureter. Materials and Methods: A catheter-mounted electrode was used to perform fluoroscopy-guided IRE in 8 healthy pigs. Two unilateral ablations (90 pulses at 2,000 V, 100 mu s) were performed in each animal in the proximal and distal ureter. Serum creatinine measurements and contrast-enhanced computed tomography imaging were performed at 1, 7, 14, 21, and 28 days after IRE, and findings were compared with baseline values by Student t test. Two animals each were euthanized at 1, 7, 14, and 28 days after IRE for histologic assessment of treatment effects. Quantitative histologic analysis of regeneration and healing of the ureteral wall was graded on a five-point scale. Results: IRE was successfully performed in all animals. Preservation of ureteral wall integrity was confirmed by the leakage-free passage of contrast medium in the treated ureter of all animals through the observation period. Ureteral strictures and associated renal pelvicaliceal dilation were observed in all animals by study days 7 (P = .005) and 14 (P = .007) and did not resolve by day 28. Urothelial recovery was observed in tissue samples from day 7, with progressive replacement of the tunica muscularis with granulation tissue. Despite extensive scarring of the tunica muscularis, full recovery of the urothelium was observed by day 28. Conclusions: The normal porcine ureter retains lumen wall integrity and function following catheter-directed IRE. Scarring of the tunica muscularis in the treated ureter results in stricture formation and reduction of lumen patency.
Sanchez-Aparicio MT, Garcin D, Rice CM, Kolakofsky D, Garcia-Sastre A, Baum A
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Loss of Sendai virus C protein leads to accumulation of RIG-I immunostimulatory defective interfering RNA

JOURNAL OF GENERAL VIROLOGY 2017 JUN; 98(6):1282-1293
Retinoic acid inducible gene (RIG-I)-mediated innate immunity plays a pivotal role in defence against virus infections. Previously we have shown that Sendai virus (SeV) defective interfering (DI) RNA functions as an exclusive and potent RIG-I ligand in DI RNA-rich SeV-Cantell infected cells. To further understand how RIG-I is activated during SeV infection, we used a different interferon (IFN)-inducing SeV strain, recombinant SeV Delta C, which, in contrast to SeV-Cantell is believed to stimulate IFN production due to the lack of the SeV IFN antagonist protein C. Surprisingly, we found that in Sev Delta C-infected cells, DI RNAs also functioned as an exclusive RIG-I ligand. Infections with wild-type SeV failed to generate any RIG-I-associated immunostimulatory RNA and this correlated with the lack of DI genomes in infected cells, as well as with the absence of cellular innate immune responses. Supplementation of the C protein in the context of SeV Delta C infection led to a reduction in the number of DI RNAs, further supporting the potential role of the C protein as a negative regulator of DI generation and/or accumulation. Our findings indicate that limiting DI genome production is an important function of viral IFN antagonist proteins.
Hamilton SM, Alexander JAN, Choo EJ, Basuino L, da Costa TM, Severin A, Chung M, Aedo S, Strynadka NCJ, Tomasz A, Chatterjee SS, Chambers HF
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High-Level Resistance of Staphylococcus aureus to beta-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4)

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY 2017 JUN; 61(6):? Article e02727-16
Penicillin-binding protein 4 (PBP4), a nonessential, low-molecular-weight penicillin-binding protein of Staphylococcus aureus, has been implicated in low-level resistance to beta-lactam antibiotics, although the mechanism is unknown. Mutations in PBP4 and its promoter were identified in a laboratory-generated mutant strain, CRB, which expresses high-level resistance to beta-lactams, including resistance to the new-generation cephalosporins active against methicillin-resistant strains of S. aureus. These mutations did not appreciably alter the beta-lactam antibiotic binding affinity of purified recombinant mutant PBP4 compared to that of wild-type PBP4. Compared to the susceptible parent strain, COLnex, the CRB strain produces a highly crosslinked cell wall peptidoglycan, indicative of increased transpeptidase activity. The pbp4 promoter mutation of CRB was associated with greatly increased amounts of PBP4 in membranes compared to those in the COLnex parent. Replacement of the native promoter of COLnex with the mutant promoter of CRB resulted in increased amounts of PBP4 in membranes and a highly cross-linked cell wall. PBP4 can be re-purposed to provide essential transpeptidase activity in vivo and confer high-level resistance to beta-lactam antibiotics, such as ceftobiprole and ceftaroline.
Tlusty T, Libchaber A, Eckmann JP
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Physical Model of the Genotype-to-Phenotype Map of Proteins

PHYSICAL REVIEW X 2017 JUN 6; 7(2):? Article 021037
How DNA is mapped to functional proteins is a basic question of living matter. We introduce and study a physical model of protein evolution which suggests a mechanical basis for this map. Many proteins rely on large-scale motion to function. We therefore treat protein as learning amorphous matter that evolves towards such a mechanical function: Genes are binary sequences that encode the connectivity of the amino acid network that makes a protein. The gene is evolved until the network forms a shear band across the protein, which allows for long-range, soft modes required for protein function. The evolution reduces the high-dimensional sequence space to a low-dimensional space of mechanical modes, in accord with the observed dimensional reduction between genotype and phenotype of proteins. Spectral analysis of the space of 10(6) solutions shows a strong correspondence between localization around the shear band of both mechanical modes and the sequence structure. Specifically, our model shows how mutations are correlated among amino acids whose interactions determine the functional mode.
Feng B, Hou DF, Liu H, Ren HC, Wu PP, Wu Y
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Chiral magnetic effect in a lattice model

PHYSICAL REVIEW D 2017 JUN 28; 95(11):? Article 114023
We study analytically the one-loop contribution to the chiral magnetic effect (CME) using lattice regularization with a Wilson fermion field. In the continuum limit, we find that the chiral magnetic current vanishes at nonzero temperature but emerges at zero temperature consistent with that found by Pauli-Villas regularization. For finite lattice size, however, the chiral magnetic current is nonvanishing at nonzero temperature. But the numerical value of the coefficient of CME current is very small compared with that extracted from the full QCD simulation for the same lattice parameters. The possibility of higher-order corrections from QCD dynamics is also assessed.
Sartaj R, Zhang C, Wan P, Pasha Z, Guaiquil V, Liu A, Liu J, Luo Y, Fuchs E, Rosenblatt MI
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Characterization of slow cycling corneal limbal epithelial cells identifies putative stem cell markers

SCIENTIFIC REPORTS 2017 JUN 19; 7(?):? Article 3793
In order to identify reliable markers of corneal epithelial stem cells, we employed an inducible transgenic "pulse-chase" murine model (K5Tta x TRE-H2BGFP) to localize, purify, and characterize slow cycling cells in the cornea. The retention of GFP labeling in slowly dividing cells allowed for localization of these cells to the corneal limbus and their subsequent purification by FACS. Transcriptome analysis from slow cycling cells identified differentially expressed genes when comparing to GFP-faster-dividing cells. RNA-Seq data from corneal epithelium were compared to epidermal hair follicle stem cell RNA-Seq to identify genes representing common putative stem cell markers or determinants, which included Sox9, Fzd7, Actn1, Anxa3 and Krt17. Overlapping retention of GFP and immunohistochemical expression of Krt15,Delta Np63, Sox9, Actn1, Fzd7 and Krt17 were observed in our transgenic model. Our analysis presents an array of novel genes as putative corneal stem cell markers.
Randolph GJ, Beaulieu S, Lebecque S, Steinman RM, Muller WA
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Differentiation of Monocytes into Dendritic Cells in a Model of Transendothelial Trafficking

JOURNAL OF IMMUNOLOGY 2017 JUN 1; 198(11):4191-4194
Essential to the dendritic cell system of antigen-presenting cells are the veiled dendritic cells that traverse afferent lymph to enter lymph nodes, where they initiate immune responses. The origin of veiled cells, which were discovered 20 years ago, is unclear. Monocytes cultured with endothelium differentiated into dendritic cells within 2 days, particularly after phagocytosing particles in subendothelial collagen. These nascent dendritic cells migrated across the endothelium in the ablumenal-to-lumenal direction, as would occur during entry into lymphatics. Monocytes that remained in the subendothelial matrix became macrophages. Therefore, monocytes have two potential fates associated with distinct patterns of migration.
Zhou Y, Crowley RS, Ben K, Prisinzano TE, Kreek MJ
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Synergistic blockade of alcohol escalation drinking in mice by a combination of novel kappa opioid receptor agonist Mesyl Salvinorin B and naltrexone

BRAIN RESEARCH 2017 MAY 1; 1662(?):75-86
Mesyl Salvinorin B (MSB) is a potent selective kappa opioid receptor (KOP-r) agonist that has potential for development as an anti-psychostimulant agent with fewer side-effects (e.g., sedation, depression and dysphoria) than classic KOP-r agonists. However, no such study has been done on alcohol. We investigated whether MSB alone or in combination with naltrexone (mu-opioid receptor antagonist) altered voluntary alcohol drinking in both male and female mice. Mice, subjected to 3 weeks of chronic escalation drinking (CED) in a two-bottle choice paradigm with 24-h access every other day, developed rapid escalation of alcohol intake and high preference. We found that single, acute administration of MSB dose dependently reduced alcohol intake and preference in mice after 3-week CED. The effect was specific to alcohol, as shown by the lack of any effect of MSB on sucrose or saccharin intake. We also used the drinking-in-the-dark (DID) model with limited access (4 h/day) to evaluate the pharmacological effect of MSB after 3 weeks of DID. However, MSB had no effect on alcohol drinking after 3-week DID. Upon investigation of potential synergistic effects between naltrexone and MSB, we found that acute administration of a combination of MSB and naltrexone reduced alcohol intake profoundly after 3-week CED at doses lower than those individual effective doses. Repeated administrations of this combination showed less tolerance development than repeated MSB alone. Our study suggests that the novel KOP-r agonist MSB both alone and in combination with naltrexone shows potential in alcoholism treatment models. (C) 2017 Elsevier B.V. All rights reserved.