Setdb1 and Atf7IP form a hetero-trimeric complex that blocks Setdb1 nuclear export.

Histone H3K9 methylation (H3K9me) by Setdb1 silences retrotransposons (rTE) by sequestering them in constitutive heterochromatin. Atf7IP is a constitutive binding partner of Setdb1 and is responsible for Setdb1 nuclear localization, activation and chromatin recruitment. However, structural details of the Setdb1/Atf7IP interaction have not been evaluated.

DNA hypomethylation promotes UHRF1-and SUV39H1/H2-dependent crosstalk between H3K18ub and H3K9me3 to reinforce heterochromatin states.

Mono-ubiquitination of lysine 18 on histone H3 (H3K18ub), catalyzed by UHRF1, is a DNMT1 docking site that facilitates replication-coupled DNA methylation maintenance. Its functions beyond this are unknown. Here, we genomically map simultaneous increases in UHRF1-dependent H3K18ub and SUV39H1/H2-dependent H3K9me3 following DNMT1 inhibition.

Global assessment of surgical skills (GASS): validation of a new instrument to measure global technical safety in surgical procedures.

Background: Broad implementation of the American Board of Surgery's entrustable professional activities initiative will require assessment instruments that are reliable and easy to use. Existing assessment instruments of general laparoscopic surgical skills have limited reliability, efficiency, and validity across the spectrum of formative (low-stakes) and summative (high-stakes) assessments. A novel six-item global assessment of surgical skills (GASS) instrument was developed and evaluated with a focus upon safe versus unsafe surgical practice scoring rubric.

High-Throughput Assay for Characterizing Rpn11 Deubiquitinase Activity.

Rpn11 is an essential metalloprotease responsible for the en bloc removal of ubiquitin chains from protein substrates that are targeted for degradation by the 26S proteasome. A unique feature of Rpn11 is that its deubiquitinase (DUB) activity is greatly stimulated by the mechanical translocation of the substrate into the proteasomal AAA+ (ATPase Associated with diverse cellular Activities) motor, which delivers the scissile isopeptide bond between a substrate lysine and the proximal moiety of an attached ubiquitin chain to the DUB catalytic active site. As a consequence, Rpn11 cleaves at the base of ubiquitin chains and lacks selectivity towards specific ubiquitin-chain linkage types, which is in contrast to other DUBs, including the related AMSH that selectively cleaves Lys63-linked chains.

Multistate structures of the MLL1-WRAD complex bound to H2B-ubiquitinated nucleosome.

The human Mixed Lineage Leukemia-1 (MLL1) complex methylates histone H3K4 to promote transcription and is stimulated by monoubiquitination of histone H2B. Recent structures of the MLL1-WRAD core complex, which comprises the MLL1 methyltransferase, DR5, bBp5, sh2L, and PY-30, have revealed variability in the docking of MLL1-WRAD on nucleosomes. In addition, portions of the Ash2L structure and the position of DPY30 remain ambiguous.

The impact of COVID-19 on medium term weight loss and comorbidities in patients undergoing bariatric surgery and its association with psychological wellbeing.

Background: The COVID-19 epidemic imposed significant stressors on individuals and changed how medical care is delivered. The affect that this stress has placed on the field of bariatric surgery and the associated outcomes is not well established.

Methods: A retrospective review of a prospectively collected database from a single academic institution was conducted.

Design Thinking for Healthcare: Transliterating the Creative Problem-Solving Method Into Architectural Practice.

Purpose: The purpose of this article is to define design thinking, provide insights into how it may be integrated into the healthcare design process, and provide a checklist for future implementation.

Background: Design thinking is a collaborative method of inquiry that fosters innovative, team-generated solutions to complex scenarios, known as "wicked problems," that are extraordinarily difficult to solve. It is a practical tool in the toolbox of the codesign team, which includes the client and design professionals as primary stakeholders.

Structural basis for COMPASS recognition of an H2B-ubiquitinated nucleosome.

Methylation of histone H3K4 is a hallmark of actively transcribed genes that depends on mono-ubiquitination of histone H2B (H2B-Ub). H3K4 methylation in yeast is catalyzed by Set1, the methyltransferase subunit of COMPASS. We report here the cryo-EM structure of a six-protein core COMPASS subcomplex, which can methylate H3K4 and be stimulated by H2B-Ub, bound to a ubiquitinated nucleosome.

Activation and regulation of H2B-Ubiquitin-dependent histone methyltransferases.

Covalent modifications of histone proteins regulate a wide variety of cellular processes. Methylation of histone H3K79 and H3K4 is associated with active transcription and is catalyzed by Dot1L and Set1, respectively. Both Dot1L and Set1 are activated by prior ubiquitination of histone H2B on K120 in a process termed 'histone crosstalk'.

Mechanism of Cross-talk between H2B Ubiquitination and H3 Methylation by Dot1L.

Methylation of histone H3 K79 by Dot1L is a hallmark of actively transcribed genes that depends on monoubiquitination of H2B K120 (H2B-Ub) and is an example of histone modification cross-talk that is conserved from yeast to humans. We report here cryo-EM structures of Dot1L bound to ubiquitinated nucleosome that show how H2B-Ub stimulates Dot1L activity and reveal a role for the histone H4 tail in positioning Dot1L. We find that contacts mediated by Dot1L and the H4 tail induce a conformational change in the globular core of histone H3 that reorients K79 from an inaccessible position, thus enabling this side chain to insert into the active site in a position primed for catalysis.

An AAA Motor-Driven Mechanical Switch in Rpn11 Controls Deubiquitination at the 26S Proteasome.

Poly-ubiquitin chains direct protein substrates to the 26S proteasome, where they are removed by the deubiquitinase Rpn11 during ATP-dependent substrate degradation. Rapid deubiquitination is required for efficient degradation but must be restricted to committed substrates that are engaged with the ATPase motor to prevent premature ubiquitin chain removal and substrate escape. Here we reveal the ubiquitin-bound structure of Rpn11 from S.

Atomic structure of the 26S proteasome lid reveals the mechanism of deubiquitinase inhibition.

The 26S proteasome is responsible for the selective, ATP-dependent degradation of polyubiquitinated cellular proteins. Removal of ubiquitin chains from targeted substrates at the proteasome is a prerequisite for substrate processing and is accomplished by Rpn11, a deubiquitinase within the 'lid' sub-complex. Prior to the lid's incorporation into the proteasome, Rpn11 deubiquitinase activity is inhibited to prevent unwarranted deubiquitination of polyubiquitinated proteins.

Structure of the Rpn11-Rpn8 dimer reveals mechanisms of substrate deubiquitination during proteasomal degradation.

Polyubiquitin chains target protein substrates to the 26S proteasome, where they are removed by the deubiquitinase Rpn11 to allow efficient substrate degradation. Despite Rpn11's essential function during substrate processing, its detailed structural and biochemical characterization has been hindered by difficulties in purifying the isolated enzyme. Here we report the 2.

Reconstitution of the 26S proteasome reveals functional asymmetries in its AAA+ unfoldase.

The 26S proteasome is the major eukaryotic ATP-dependent protease, yet the detailed mechanisms used by the proteasomal heterohexameric AAA+ unfoldase to drive substrate degradation remain poorly understood. To perform systematic mutational analyses of individual ATPase subunits, we heterologously expressed the unfoldase subcomplex from Saccharomyces cerevisiae in Escherichia coli and reconstituted the proteasome in vitro. Our studies demonstrate that the six ATPases have distinct roles in degradation, corresponding to their positions in the spiral staircases adopted by the AAA+ domains in the absence or presence of substrate.

Ascorbic acid and a cytostatic inhibitor of glycolysis synergistically induce apoptosis in non-small cell lung cancer cells.

Ascorbic acid (AA) exhibits significant anticancer activity at pharmacologic doses achievable by parenteral administration that have minimal effects on normal cells. Thus, AA has potential uses as a chemotherapeutic agent alone or in combination with other therapeutics that specifically target cancer-cell metabolism. We compared the effects of AA and combinations of AA with the glycolysis inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3-PO) on the viability of three non-small cell lung cancer (NSCLC) cell lines to the effects on an immortalized lung epithelial cell line.

Lethal factor unfolding is the most force-dependent step of anthrax toxin translocation.

Cellular compartmentalization requires machinery capable of translocating polypeptides across membranes. In many cases, transported proteins must first be unfolded by means of the proton motive force and/or ATP hydrolysis. Anthrax toxin, which is composed of a channel-forming protein and two substrate proteins, is an attractive model system to study translocation-coupled unfolding, because the applied driving force can be externally controlled and translocation can be monitored directly by using electrophysiology.

Associative ionization of laser-excited Rydberg states in strontium vapor.

Using mass spectrometry we have confirmed that Sr(2)(+) ions are produced from laser-populated Rydberg states by the associative ionization process Sr(5snl) + Sr(5s(2)) ? Sr(2)(+) + e(-). Dimer ion signal was detected for the 5s6d(3)D(2) level, indicating that the binding energy of Sr(2)(+) exceeds 0.77 eV.

Temperature Classification of the Spectra of Dysprosium (Dy i, Dy ii).

The Temperature Classifications are listed for 4584 lines of Dy i and Dy ii, as taken from an unpublished manuscript of the late A. S. King.