No abstract

Extracorporeal cardiopulmonary resuscitation showed a survival benefit over conventional cardiopulmonary resuscitation in patients who received cardiopulmonary resuscitation for >10 mins after witnessed inhospital arrest, especially in cases with cardiac origins.

Here we report an analysis of the subunit composition and substrate specificity of the NSL complex. Proteomic analyses of complexes purified through multiple candidate subunits reveal that NSL is composed of nine subunits. Two of its subunits, WD repeat domain 5 (WDR5) and host cell factor 1 (HCF1), are shared with members of the MLL/SET family of histone H3 lysine 4 (H3K4) methyltransferase complexes, and a third subunit, MCRS1, is shared with the human INO80 chromatin-remodeling complex. In addition, we show that assembly of the MOF HAT into MSL or NSL complexes controls its substrate specificity. Although MSL-associated MOF acetylates nucleosomal histone H4 almost exclusively on lysine 16, NSLassociated MOF exhibits a relaxed specificity and also acetylates nucleosomal histone H4 on lysines 5 and 8.In eukaryotic cells, chromosomal DNA is packaged with histones and other proteins into chromatin. Alterations in chromatin structure affect the accessibility of chromosomal DNA to enzymes involved in transcription, replication, and repair. Changes in chromatin structure are regulated in at least three different ways: by ATP-dependent remodeling of nucleosomes, by the incorporation of variants of histones H2A and H3 into nucleosomes, and by post-translational modifications of histones (1-5).Post-translational modifications of histones include acetylation, methylation, phosphorylation, ubiquitination, sumoylation, and ADP-ribosylation (4 -6). Reversible histone acetylation, controlled by histone acetyltransferases (HATs) 4 and histone deacetylases, plays an important role in regulation of chromatin structure and function (3, 7). Based on the nature of their catalytic domains, HATs can be grouped into two distinct families: the GCN5-related N-acetyltransferase (GNAT) family, which includes GCN5 and p300/CBP-associating factor (8), and the Moz-Ybf2/Sas3-Sas2-Tip60 (MYST) family, which is characterized by a highly conserved MYST domain composed of an acetyl-CoA binding motif and a zinc finger (9, 10). Some MYST family members also have additional structural features such as chromodomains (MOF, Esa1, and Tip60), plant homeodomain-linked zinc fingers (Moz and MORF), and other domains that bind specifically to modified histones or participate in other protein-protein interactions (10).Human MOF is an ortholog of the Drosophila MOF HAT. MOF is one of the key components of the dosage compensation or male-specific lethal (MSL) complex. The Drosophila MSL complex is composed of at least five proteins (MSL1, MSL2, MSL3, MLE, and MOF) and two non-coding RNAs (roX1 and roX2). Human cells express an evolutionarily conserved MSL complex that is composed of MOF and at least three additional subunits, including orthologs of MSL1, MSL2, and MSL3. The MOF HAT is believed to be responsible for the majority of histone H4 acetylation at lysine 16 in both Drosophila and human cells (4,(11)(12)(13).Results of recent studies suggest the existence of additional MOF-containing HAT complexes. Roeder and co-workers (14) reported that in addition...

Background-The optimal duration of dual antiplatelet therapy (DAPT) after implantation of drug-eluting coronary stents remains undetermined. We aimed to test whether 6-month DAPT would be noninferior to 12-month DAPT after implantation of drug-eluting stents. Methods and Results-We randomly assigned 1443 patients undergoing implantation of drug-eluting stents to receive 6-or 12-month DAPT (in a 1:1 ratio). The primary end point was a target vessel failure, defined as the composite of cardiac death, myocardial infarction, or ischemia-driven target vessel revascularization at 12 months. Rates of target vessel failure at 12 months were 4.8% in the 6-month DAPT group and 4.3% in the 12-month DAPT group (the upper limit of 1-sided 95% confidence interval, 2.4%; Pϭ0.001 for noninferiority with a predefined noninferiority margin of 4.0%). Although stent thrombosis tended to occur more frequently in the 6-month DAPT group than in the 12-month group (0.9% versus 0.1%; hazard ratio, 6.02; 95% confidence interval, 0.72-49.96; Pϭ0.10), the risk of death or myocardial infarction did not differ in the 2 groups (2.4% versus 1.9%; hazard ratio, 1.21; 95% confidence interval, 0.60 -2.47; Pϭ0.58). In the prespecified subgroup analysis, target vessel failure occurred more frequently in the 6-month DAPT group than in the 12-month group (hazard ratio, 3.16; 95% confidence interval, 1.42-7.03; Pϭ0.005) among diabetic patients. Conclusions-Six-month DAPT did not increase the risk of target vessel failure at 12 months after implantation of drug-eluting stents compared with 12-month DAPT. However, the noninferiority margin was wide, and the study was underpowered for death or myocardial infarction. Our results need to be confirmed in larger trials. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00698607. (Circulation. 2012;125:505-513.)

Heterogeneous transcriptional start site usage by HIV-1 produces 5′-capped RNAs beginning with one, two, or three 5′-guanosines (Cap1G, Cap2G, or Cap3G, respectively) that are either selected for packaging as genomes (Cap1G) or retained in cells as translatable messenger RNAs (mRNAs) (Cap2G and Cap3G). To understand how 5′-guanosine number influences fate, we probed the structures of capped HIV-1 leader RNAs by deuterium-edited nuclear magnetic resonance. The Cap1G transcript adopts a dimeric multihairpin structure that sequesters the cap, inhibits interactions with eukaryotic translation initiation factor 4E, and resists decapping. The Cap2G and Cap3G transcripts adopt an alternate structure with an elongated central helix, exposed splice donor residues, and an accessible cap. Extensive remodeling, achieved at the energetic cost of a G-C base pair, explains how a single 5′-guanosine modifies the function of a ~9-kilobase HIV-1 transcript.

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Mutation of the adenomatous polyposis coli (APC) tumor suppressor stabilizes b-catenin and aberrantly reactivates Wnt/b-catenin target genes in colon cancer. APC mutants in cancer frequently lack the conserved catenin inhibitory domain (CID), which is essential for b-catenin proteolysis. Here we show that the APC CID interacts with a-catenin, a Hippo signaling regulator and heterodimeric partner of b-catenin at cell:cell adherens junctions. Importantly, a-catenin promotes b-catenin ubiquitylation and proteolysis by stabilizing its association with APC and protecting the phosphodegron. Moreover, b-catenin ubiquitylation requires binding to a-catenin. Multidimensional protein identification technology (MudPIT) proteomics of multiple Wnt regulatory complexes reveals that a-catenin binds with b-catenin to LEF-1/TCF DNA-binding proteins in Wnt3a signaling cells and recruits APC in a complex with the CtBP:CoREST:LSD1 histone H3K4 demethylase to regulate transcription and b-catenin occupancy at Wnt target genes. Interestingly, tyrosine phosphorylation of a-catenin at Y177 disrupts binding to APC but not b-catenin and prevents repression of Wnt target genes in transformed cells. Chromatin immunoprecipitation studies further show that a-catenin and APC are recruited with b-catenin to Wnt response elements in human embryonic stem cells (hESCs). Knockdown of a-catenin in hESCs prevents the switch-off of Wnt/b-catenin transcription and promotes endodermal differentiation. Our findings indicate a role for a-catenin in the APC destruction complex and at Wnt target genes.

Rapid Myc protein turnover is critical for maintaining basal levels of Myc activity in normal cells and a prompt response to changing growth signals. We characterize a new Myc-interacting factor, TRPC4AP (transient receptor potential cation channel, subfamily C, member 4-associated protein)/TRUSS (tumor necrosis factor receptor-associated ubiquitous scaffolding and signaling protein), which is the receptor for a DDB1 (damage-specific DNA-binding protein 1)–CUL4 (Cullin 4) E3 ligase complex for selective Myc degradation through the proteasome. TRPC4AP/TRUSS binds specifically to the Myc C terminus and promotes its ubiquitination and destruction through the recognition of evolutionarily conserved domains in the Myc N terminus. TRPC4AP/TRUSS suppresses Myc-mediated transactivation and transformation in a dose-dependent manner. Finally, we found that TRPC4AP/TRUSS expression is strongly down-regulated in most cancer cell lines, leading to Myc protein stabilization. These studies identify a novel pathway targeting Myc degradation that is suppressed in cancer cells.